I Strawberry Culture in Wisconsin W AGRICULTURAL EXPERIMENT STATtON UNIVERSITY OF WISCONSIN, MADISON Strawberry Culture In Wisconsin James G. Moore HE STRAWBERRY is the most important small fruit grown in Wisconsin, both commercially and for home use. The reasons for its great popularity are, ease of culture, earliness, short period between planting and fruiting, comparative freedom from pests, adaptability to varying conditions, and the great popularity of the fruit itself. It is grown for home use in all parts of the state. Com- mercially it is largely confined to areas reasonably near large markets, but in a few sections it is produced strictly for whole- sale markets. The selection of the site has much to do with success, particularly where this fruit is grown commercially. It is an important factor in earliness and prevention of injury from late spring frosts. If ex- ceptionally early fruit, which brings maximum prices, is desired, safety — — To Succeed With Strawberries Select site for plantation with care. Prepare the soil thoroughly. Keep the soil fertile. Plant adapted varieties. Use only good plants. Set plants properly. Keep the soil thoroughly tilled. Protect plants and fruit by using a mulch. Place only good fruit on the market. Make the package attractive. Choose Plantation Site Carefully Strawberry Culture In Wisconsin 3 from frost injury must be sacrificed to a considerable degree. For such a crop select a site with a southern exposure and preferably with a light soil. If earliness is not of prime importance, choose a northern slope to retard the flowing period, which lessens the danger from injury from late frosts, and causes later ripening of the fruit. The slope should be gentle so as not to favor serious soil washing. The selection of the site for the home plantation is not so important. Nearness to the house is usually of more importance than either earliness or greater safety from frost injury. Select as Good a Soil as Possible There is no one "best soil" for strawberries. The crop is grown commercially on soil of practically all types, ranging from rather light sands to heavy clay and black prairie loams. On each, excellent re- sults are secured if proper cultural practices are followed and the right varieties grown. For commercial plantations, a deep, rich, well- drained sandy loam is usually preferred. Certain qualities are necessary in any soil if good results are to be secured. Ability to retain moisture is of first importance, as the pro- duction of heavy croos demands large amounts of moisture. Ordinarily rains at fruiting time are insufficient for the needs of the crop. This is especially true if the greater part of the spring rains has run off instead of being absorbed by the soil. The soil should be in condition to catch and hold the moisture. The ability of the soil to do this de- pends upon its texture, organic content and physical condition. Water runs off a soil with compact surface. Lumpy, cloddy soils lose their moisture much more readily than those of fine tilth. Decaying vegetable (organic) matter in the soil increases its water-holding capacity. Soils which do not and cannot be made to possess these requisites should be avoided in selecting a site for growing strawberries. The plant-food content of the soil should not be overlooked. Com- paratively fertile soils are most desirable. If a soil is ideal in other respects, however, deficiency in plant food should not deter one from selecting it for a strawberry plantation, as such deficiency can be over- come. If a soil selected does not contain a liberal amount of decaying vegetable matter, it should be applied in preparing the soil to receive the plants. Such material, in addition to influencing the water-Jiolding ability of the soil, bears an important relation to its productiveness. This is one of the reasons why new land gives such satisfactory re- sults when planted to small fruits. Good drainage is necessary. While an abundance of soil moisture is advantageous, an excess is very harmful. The water table should be a sufficient distance below the surface to allow for good root develop- ment. It should also be possible for excessive soil moisture to be carried away readily. 4 Wisconsin Bulletin 360 Thorough Soil Preparation Pays Good soil preparation will repay the grower in lessened work later on and usually produces larger crops of finer fruit than if it is poorly done. Four things in particular need to be taken into account in prepar- ing the soil. These are: the control of pests; the plant food and organic matter content of the soil; and the tilth. Preferably the tract chosen should have grown a cultivated crop one or two years before being planted to strawberries. The cultivation lessens the danger of injury from the white grub; weeds are less likely to prove troublesome; and a good tilth is more easily secured under such conditions. If it is necessary to use sod land it should be spaded or plowed during the summer or fall previous to planting so as to give as much chance as possible for the sod to rot. Liberal amounts of plant food are essential to the production of large crops. There is little danger of getting a strawberry soil too rich. In practically all cases it will be desirable to increase the plant food at the time of preparing the soil. Most growers prefer to use well rotted manure for this purpose. It is usually more economical to sup- plement the manure with commercial fertilizer. If necessary to use coarse (unrotted) manure, it should be applied in preparing the soil for the crop preceding the strawberry. If fairly well rotted it may be applied the fall preceding setting of the plantation and plowed under. Well rotted manure is ordinarily applied before plowing in the spring. If very fine, it may be used as a top dressing after plowing and worked into the soil. No Set Rule To Follow So much depends upon the natural fertility of the soil and its previous cropping and fertilization that no general formula for the ap- plication of fertilizer would apply in all cases. Growers will find it necessary to determine largely for themselves by field trials what is lacking and then increase the element or elements which are deficient. The amount of manure used varies greatly. The average applica- tion is from ten to twenty tons or loads per acre. Some growers use as much as forty loads per acre. It would seem to be more economical, in most cases, to use a smaller amount and supplement it by using com- mercial fertilizers. Possibly a better way to determine the amount of manure to apply would be on the basis of the organic matter needed. Under this method enough manure would be put on, if available, to give the desired amount of organic matter. It would then be sup- plemented, if desirable, with from 200 to 400 pounds of acid phosphate and possibly 50 to 100 pounds of nitrate of soda or sulphate of ammonia. Some growers prefer a complete commercial fertilizer either used alone or supplementing the manure. A fertilizer containing 3 per cent Strawberry Culture In Wisconsin 5 nitrogen, 7 per cent phosphoric acid and 9 per cent potash, called a 3-7-9 mixture is usually chosen. A mixed fertilizer of this composition may be bought but where considerable quantities are needed, it is usually more economical to purchase the materials carrying the desired elements and mix them at home. When used without manure it is a good plan to have the nitrogen carried in two forms — one in which it is readily available and the other more slowly available. It is impossible to state just what amounts would give best results, but Table I is suggestive of the -quantity of various common fertilizers which will furnish desired amounts of plant food! Table I. — Some Fertilizers and Suggested Rates of Application Fertilizer Per cent strength Pounds per acre Pounds element Nitrate of soda 15 N 20 N 14 N 100-200 100-200 200-300 15-30 N 20-40 N 28-42 N Sulphate of ammonia Dried blood Vluriate of potash 50 K 2 0 48 K 2 0 100-200 100-200 41-82 K 40-80 K Sulphate of potash 3one meal 21 P 2 0 6 15 P 2 0 5 250-400 350-500 23-37 P 23-33 P Vcid phosphate N— Nitrogen; K.,0— Potash; P 2 0 5 —Phosphoric Acid; K — Potassium; P — Phosphorus. In mixing these materials to make the 3-7-9 fertilizer recommend- ed it is possible to adjust the proportions in various ways. To indicate how the problem may be solved two such mixtures are shown in Table II. Table II.— Suggested Fertilizer Mixtures Fertilizer Per cent strength Amount in pounds Pounds of plant food Mixture I Nitrate of soda 15 N 15 P,0 6 48 K,0 100 225 95 15N 35 P 2 0 5 45 K 2 0 Acid phosphate Sulphate of potash Mixture II Dried blood 14 N 21 P„0 5 50 K.~0 150 125 180 21 N 49 P 2 0 5 63 K 2 0 Bone meal Muriate of potash 6 Wisconsin Bulletin 360 In these formulas if nitrogen is to be carried in two forms, ap- proximately equal amounts of nitrate of soda or sulphate of ammonia and dried blood should be used. Choice cotton seed meal can be sub- stituted for dried blood. To give the same amount of nitrogen, double the amount of cotton seed meal should be used. There is practically no danger of increasing any of the elements to an injurious extent except nitrogen. An excessive amount of this element has a tendency to cause heavy vegetative growth at the ex- pense of fruit production. When used as supplementing manure, the amount of nitrogen may be reduced. In doing this it is probably best to leave out the less readily available form. Commercial fertilizers should be put on after plowing and thoroughly mixed into the soil. Do Not Neglect the Organic Matter Increased amount of plant food in the soil is of little value to plants unless there is an abundance of organic matter present. Fre- quently so-called poor soils have sufficient plant food but are unpro- ductive because of insufficient organic matter. As previously pointed out, the use of manure is the common method of increasing the organic matter content of soil. If sufficient manure or similar litter cannot be secured then it is necessary to resort to green manuring. Any crop which produces a large vegetative growth in a relatively short period may be used. When leguminous crops are grown for green manuring ihe nitrogen content of the soil is also increased. Some growers supply organic matter largely by growing clover in the rotation in advance of the cultivated crop preceding the strawberries. Good Tilth is Very Important Soil which is to be planted to strawberries should be plowed or spaded fairly deep. The heavier types of soil should be plowed deeper than the lighter ones. Fall plowing is desirable particularly on heavy soils. When this is done discing or shallow plowing should be the first tillage operation in the spring. Thorough harrowing, planking, or other cultivation should follow to put the soil in as fine tilth as possible. It is particularly important that the upper two or three inches be loose and friable in order that planting may be facilitated and soil moisture conserved. Some soils may be so loose and open as to make rolling desirable. If done, it should be followed immediately by harrowing to retard the escape of moisture. Strawberry Culture In Wisconsin 7 How to Select the Plants Good plants are necessary for the best results. When the plants for the new plantation are bought, there is little chance for selection but on the other hand, if the grower takes the plants from an old plantation, he can carefully select them. Three things largely de- termine the desirability of a plant: Age, character of the root system, and freedom from pests. The plants should be strong and vigorous, aris- ing from runners of the same season or in the case of spring planting from the season previous to the time of planting. Old, fruited plants should not be used. It is desirable to have a plant with good top growth. It is more im- portant, however, that it possess a good root system. A plant with a large healthy root system and a comparatively small top is much to be preferred to one in which these con- ditions are reversed. The former will soon develop a FIG - 1-ONLY STRONG PLANTS ARE WORTH large top while the latter PLANTING will find much difficulty in The plant at the left is too young and putting out new growth. weak. Care for the plants properly on their arrival. Neglect at this time frequently results in failure to get a good stand. Often plants are shipped long distances or are delayed in transit and so arrive in poor condition. Lack of proper attention means a loss of the plants, as well as time and labor. Even plants arriving in good condition deteriorate rapidly if not properly cared for. Remove the plants from the package as soon as they are received and heel them in. This process consists in placing the plants in the soil in loosely compact rows. Select a location protected from sun and wind. Spade up the soil, putting it in the same condition as it would be if the plants were to be set permanently. Make a broad V-shaped trench about eight inches deep. Open the bundles and distribute the plants along the trench just far enough apart to allow the root system of each to come fully in contact with the soil. Refill the trench, com- pressing the soil, being careful that the crowns are not covered nor the upper part of the roots exposed. Place the variety label at the end of 8 Wisconsin Bulletin 360 the row to avoid any danger of mixing varieties later on. Water the plants thoroughly after heeling-in. If early in the spring, the plants should be mulched to prevent injury from freezing and in this way may FIG. 2.— HEELING-IN SAVES PLANTS AND DISAPPOINTMENTS Plants should be properly heeled-in as soon as received. be kept for some time without being injured. However, the length of time they are left heeled-in should be as short as possible. Spring Planting Usually Best Spring planting is usually more successful under Wisconsin con- ditions. Sometimes home plantations are set in August or early in September, so that fruit may be harvested the next season. This pro- cedure is questionable and in commercial plantings is to be dis- couraged. The systems of setting plants vary with the extent of the planta- tions and the whims of the grower. Three more or less distinct systems of planting and various modifications of these are in use. They are the hill, hedge row, and matted row systems. The matted row is used al- most entirely in this state. In this system the runner plants are spaced about 6 to 8 inches apart until they take up the entire area devoted to the row. The distance between plants in the row varies primarily with the ability of the plant to produce runners and the system of planting. Except in the hill system, it is most largely dependent upon the ability of the plant to produce runners. Some varieties, like Senator Dunlap Strawberry Culture In Wisconsin 9 and Sample, throw out numerous long runners and will need to be planted farther apart than the Bubach, Chesapeake and other shy plant- makers. The distance between plants in the row varies from fifteen to thirty inches. The most common distance is 24 inches. System of planting and method of tillage determine the distance be- tween rows. Where hand tillage is practiced, rows in the hill and single-hedge row systems may be 30 inches apart. Thirty-six inches is about the minimum for the double-hedge row and matted row. Where horse cultivation is used, these distances will need to be increased 6 to 12 inches. The usual distance for the matted row, when horse cultivation is used, is 3^> or 4 feet. The number of plants required to set an acre varies with the dis- tance of planting. Table III gives the number for various distances of planting. Table III. — Number of Plants Per Acre Planted in Hills, Double- Hedge, and Matted-Row Systems Distance between Plants Rows Plants Inches Feet 15 15 15 18 18 18 24 24 24 30 30 30 3 3.5 4 3 3.5 4 3 3.5 4 3 3.5 4 11,616 9,955 8,712 9,680 8,298 7,260 7,260 6,223 5,445 5,808 4,979 4,356 In planting it is desirable to have the field marked out in at least one direction. If marked in one direction only, it probably should be done at right angles to the direction of the row as this gives the loca- tion of the plants in the row. The rows may be kept straight by the use of a garden line. Care should be exercised not to crowd the line out of place as crooked rows result. Some growers place the line 6 "inches to one side of the place where the plants are to be set and then measure with the spade or trowel for the exact location of the plant. This prevents difficulty arising from the shifting of the line. Some growers mark the rows and estimate the proper location of the plants in the row. In large plantations marking both ways is preferable. There are several ways of doing this, the most common being an especially con- 10 Wisconsin Bulletin 360 structed sled or pole marker of the corn-marker type, but with ad- justable runners or pins. It is preferable to have rows run north and south whenever possible as this provides an equal distribution of sun- shine to both sides of the row. Prune Before Planting Pruning is usually necessary before setting the plants. It consists in reducing the top and shortening the roots. Top pruning is usually done at planting. All dead leaves, and the greater portion of the live ones should be removed. Only one or two small, healthy leaves should be left, as they are suffi- cient for the needs of the plant at that time, a much larger number being likely to prove injurious by caus- ing too much transpiration. Root-pruning consists in cutting off the ends of the roots, leaving the roots three to four inches long. The roots should be kept as long as possible and still not interfere too seriously in planting. This operation is performed when the plants are heel- ed-in or just before the setting. If plants are to be left heeled-in for a con- siderable time, it is better to defer the root pruning until planting time. Exercise Care in Setting Three things are es- sential in setting strawberries : (1) The plants must be set at the proper depth; (2) the soil must come in firm contact with the roots; and (3) the roots must not be allowed to become dry during the setting. The plants should be so set that the soil covers the base of the crown of the plant. Deeper planting covers the crown, and the bud may not be able to push out of the soil. Shallower planting exposes the upper portion of the roots and the plant is killed by the roots drying out. The soil should be pressed firmly against the roots so as to bring all points in contact with the soil. If this is not done, the plant is unable to secure enough water to sustain life. In order to bring all FIG. 3. — UNPRUNED AND PRUNED PLANTS Pruning facilitates planting and enables the plant to get a better start. Strawberry Culture In Wisconsin 11 parts of the roots in contact with the soil, they should be spread out as much as practicable. Good results can be secured without spend- ing additional time to spread out the roots. To allow the roots to dry out during planting is usually fatal. Provision should be made for keeping them moist at all times. This is usually done by putting the plants into a pail of water or by wrapping them in a wet cloth. Sometimes a boy is employed to drop the plants ahead of the men who set them. If this method is followed, it is very important to see that the boy is not more than two or three plants ahead of the planter at any time. Methods of Setting Methods of setting vary somewhat. The trowel or dibble and spade methods are commonly used. In some cases, on light soils in extra good tilth, the opening for the plant is made with the hands. Some growers prefer the spade, while others will have nothing but the dibble, claiming that it is more rapid and insures better work. Either method is satisfactory if care is exercised in doing the work, but neither will give good results if the work is carelessly done. When setting large acreages some growers use a planting machine such as is used in setting cabbage or tobacco. In dibble planting each planter works independently. The dibble is thrust into the soil and by a sidewise movement an opening is made for the plant. The roots are thrust into the opening, lowering the plant somewhat below the height it is to stand. It is then raised to its permanent position so that the roots may be well spread out and placed naturally instead of being crowded into a bunch. The dibble is then thrust into the soil at a slight distance from the plant and soil is 12 Wisconsin Bulletin 360 FIG. 5.— PLANTING WITH A DIBBLE Considered by many the best method of setting plants. Strawberry Culture In Wisconsin 13 crowded against the roots. The second opening is filled by knocking loose earth into it. In dibble planting, the men usually work in teams of three. One drops the plants ; the other two set them. When planting by the spade method two men work together, one to handle the spade and one to prune and place the plants. A smooth, bright spade is necessary, as the soil will stick to a rusty one. The spade is thrust into the soil from two- thirds to three-fourths the length of the blade. In this operation fig. 6.— SOME GOOD DIBBLES the back of the spade is away The dibble is an efficient implement from the operator. Bv a for- for setting strawberries. , , , , ward and backward movement an opening is made in the soil. The spade is then either wholly or partly removed, depending upon how great a tendency the soil has to fall into the opening. The man who places the plant, work- ing on the opposite side of the row, grasps the plant between his thumb and the palm of his hand, and using fingers to spread the roots, insets them into the opening with a sort of swinging motion. The spade- operator again pushes the spade into the soil this time two or three inches from the plant and presses soil against the roots. Meanwhile the man who places the plants presses the soil on the opposite side of the plant with his foot which insures a good contact between the soil and roots. As with the dibble method, the second hole made in planting is then filled. Care Needed After Planting Cultivate immediately after planting in order to: (1) Conserve moisture. (2) increase the available food supply; and (3) destroy weeds which affect both moisture and food supply. The conservation of moisture dur- ing the summer months following FIG. 7.— SPREAD ROOTS An easy method of accomplish- ing this result in spade planting. 14 Wisconsin Bulletin 360 planting is the most important result of proper cultivation. If the soil is left compact after planting, or allowed to become compact during the summer, the loss of soil moisture takes place rapidly and in such quantities that the plant soon reaches a point where further growth is reduced or entirely checked. No matter how much available plant food may be present in the soil, without soil moisture the plant is unable to use it. Cultivation, therefore, must be of such a nature as to provide the most effective means of conserving all the soil moisture possible. If this be done, plant food will be made available and weeds will be kept down. The best practical means of conserving soil moisture is by main- taining a soil mulch of one or two inches on the surface. To do this, frequent cultivation is necessary. The soil should be stirred at least once every ten days or two weeks and following each rainfall which compacts the surface soil. Cultivation should take place as soon after a rain as the soil will permit. The cultivation should be shallow. A soil mulch of one to two inches is effective in conserving moisture, and as the strawberry is a shallow-rooted plant, deep cultivation might severely injure the root system. Cultivation should be in two directions if possible until the runners begin to form, when it must be confined to one direction. Hoe about the plants immediately after planting to loosen the surface of the soil. Other hoeings may be given with profit if time permits. The stirring of the soil should continue throughout the season or until the plant has practically ceased growing. Grow Plants First Season The fruiting of plants during the same season as planted or the first season after planting, if set in the fall, is to be discouraged, ex- cept in home gardens and with everbearing sorts. The plants should exert all their activity the first year in producing good vigorous crowns and strong runner plants. In order to conserve all the strength of the plants for this purpose the buds or blossoms should be removed as soon as possible after being formed. Runner plants should be selected as soon as possible and given conditions which will insure quick rooting. Their distribution will de- pend upon the system of planting in use. In matted rows the plants should be kept from six to eight inches apart to prevent the rows be- coming too thick. The amount of time which can be profitably spent placing runners will depend quite largely upon the cost of available labor. Why Mulch Strawberry Beds? Mulching is one of the essentials of successful strawberry culture. In Wisconsin its chief uses are to prevent heaving of the plants in Strawberry Culture In Wisconsin 15 spring and to keep the fruit clean. These make the use of mulch im- perative in a majority of instances, but there are other advantages to be gained by its use. Moisture is conserved during the spring months, the weeds are kept down, fruiting may be retarded somewhat if desir- able, and the soil is kept from baking. A good mulch should be free from weed seed, spread evenly and break up readily in the spring. Various materials possess more or less fully these desirable qualities. Wheat or oat straw; coarse, strawy horse manure; and marsh hay are the three in most common use, al- though any one of these may be objectionable if it has too many weed seeds. Marsh hay if cut at the proper time is less likely to have weed seeds, but in any case the hay should be cut before the seed ripens enough for germination, or before it becomes very objectionable. Neither marsh hay nor manure break up in the spring so well as wheat- straw, but the manure has the advantage of adding plant food. Oat straw is frequently too foul with weeds to make a good mulch. Shredded corn stalks and pine needles are sometimes used for mulch- ing. The mulch is usually applied in the fall. Most growers wait until the ground is frozen permanently; others apply it shortly before freez- ing, claiming that there is less danger of injury to the plants due to alternate freezing and thawing. In the northern part of the state, where heavy falls of snow come early and remain on the ground dur- ing the winter, growers frequently do not apply the mulch until spring. It is doubtful if this is the best practice. The depth of the mulch will vary with different conditions. If ap- plied in the spring, it may be distributed thinly over the rows. In the fall it should be heavier so as to prevent alternate freezing and thaw- ing of the ground in the spring. It should not be so thick, however, as to smother the plants. The usual depth under Wisconsin conditions is two to four inches after the mulch has settled. When to Remove Mulch The time of removing a mulch, applied in the fall, depends upon the seasonal conditions and the time the fruit is desired. As the chief object is to prevent the heaving action of alternate freezing and thaw- ing, the mulch should be left until such danger is past. It is also well to leave the mulch long enough to retard blossoming sufficiently to escape late frosts. If it is desirable to use the mulch as a means of retarding the ripening of the fruit, the mulch may be left until the plants begin to push a few leaves up through it. It should not be left so long, how- ever that considerable growth takes place beneath it. If early fruit is desired, remove the mulch as early as possible, even taking some chances of injury from late frosts. 16 Wisconsin Bulletin 360 If the mulch be a light one, about all that is necessary is to loosen it somewhat so that the plants will be able to grow through it. If heavy, it is necessary to rake off a portion and place it between the rows. Occasionally, where the space not occupied by plants is small, it may be found necessary to remove part of the mulch from the field. It should be remembered that all the mulch should not be re- moved from the plants. The plants should grow up through enough mulch to keep the ripened fruit from coming in contact with the soil. There is no sale for dirty or sandy berries. Do not leave chunks of mulch over the plants, as this will cause injury. Some growers practice cultivation from the time the soil is fit to work until the berries are half grown. In such cases the mulch remov- ed from over the rows must be hauled off and replaced again at fruit- ing time. This, however, is not the common practice, as the average grower lets the mulch conserve the moisture and keep down the weeds until after fruiting. Caring for the Crop Harvesting seems to be one of the most trying operations of straw- berry culture, primarily because of the difficulty of getting reliable pickers. If the strawberry is to reach the market in a salable con- dition, it must be handled carefully and with the utmost attention to details. It is difficult to get the average picker to realize the im- portance of these things. The strawberry is a very tender fruit and should be picked by pinching off the stems, but the stems should not be left long. Pulling the berry from the plant should not be allowed, as many berries are partly crushed or the stem and calyx pulled out, both of which result in rapid deterioration and failure to stand up well in transit. Supply the picker with a carrier holding from four to six boxes. When the picking is good, the larger number is not too many, but when the fruit is ripening slowly and it requires some time to pick a boxful, fewer boxes should be picked before taking them to the pack- ing-shed. It should be the aim to get the berries into the shade as soon after they are picked as practicable. If left to stand in the full sunlight, a box of berries is spoiled in a very short time. Some growers attempt to have their pickers grade the berries when picking. This is practicable only when the pickers are above the average or the fruit exceptionally uniform, and is not satisfactory if a grower is building up a reputation for superiority. The average boy or girl who picks berries is not to be trusted to sort or grade them. In most cases, therefore, it is more satisfactory to have the pickers give no attention to this matter and provide an additional force to grade and pack the fruit. Strawberry Culture In Wisconsin 17 The question of how ripe the fruit should be when picked is one which bothers many growers. Varying conditions make it impossible to give a definite rule. Much depends upon the distance the fruit must be transported before reaching its destination. For home use, the berry should be allowed to become fully ripe, as then it will have a better flavor. If designed for the local market, the fruit should be The carrier facilitates harvesting. When picking is poor, reduce the number of boxes given the picker at any one time. entirely colored, but showing light at the tip and on the lower side, while for distant markets the berries should be red on the exposed side, and pink or slightly white on the underside or at the tip. In order to secure fruit of the right degree of ripeness, pickings must be fre- quent. As a rule not more than one day should intervene between pickings, and if the weather is hot and the berries are ripening fast, picking every day is better if practicable. Fruit should not be picked, however, when wet. Just how much additional time should be spent in sorting, grading, and packing the fruit depends upon the individual grower or the ex- change through which the fruit is handled. Some sorting and grading is always necessary if a good, attractive product is to be placed on the market. A good sorting table may be made of a piece of cheese cloth fastened to a frame. Where careful grading and packing are done, one packer can take care of the fruit from three pickers. The permanence of the bed is a question upon which it is im- possible to get growers to agree. Some growers harvest but one crop from a field while others take as many as three. In beds for home FIG. 8.— TWO TYPES OF CARRIERS Handling the Bed after Harvest is Wisconsin Bulletin 360 use this number is exceeded at times. The number of crops which it is profitable to harvest from a plantation depends primarily on the question of whether the plants are in good condition and whether or not it will be cheaper to renovate the old bed than to start a new one. Both of these factors depend largely upon the care that has been given the field. If careful attention has been given to thinning out the plants, keeping pests in check, preventing the weeds from seeding, and adding The following rules for picking and handling strawberries are in force in one of the western fruit exchanges. (1) Berries must not be picked while there is moisture on plants (2) Berries should be pink all over, or three-fourths red (3) Berries should be picked riper in cool weather than in warm (4) A picker must not be allowed to hold more than one or two berries in his hand at the same time (5) Filled carriers must not be allowed to stand in the sun (6) Berries must be picked with a stem a quarter of an inch long and not longer or shorter (7) Sort out all green, over-ripe, misshapen, and small berries (8) No culls in boxes. Put in nothing but fair-sized berries (9) Use clean crates and keep them from being soiled (10) Haul in spring wagon and cover to keep out the dust plant food, a larger number of crops may be removed than if these matters are given only ordinary attention. Weeds play an important part in the consideration, and as a rule the difficulty with which they are controlled makes it inadvisable to crop more than two years. As indicated above, some growers harvest but one crop, claiming that it is cheaper to start a new plantation than to renovate the old one. Those who harvest two crops claim larger yields for the second crop than for the first. Renovating the old bed is essential if a second crop is to be harvested. This operation differs with different growers and with Strawberry Culture In Wisconsin 19 different systems of planting. As the matted row is the most common form in Wisconsin, directions for renovating will be for plantations of that system. Mow and Destroy Old Foliage Developing strong new growth is an important consideration. As a considerable portion of the foliage has become more or less injured during harvesting and is likely to be infested with both fungous and insect pests, it is usually desirable to get rid of the old foliage and per- mit new to develop. The most economical method of removing the old growth seems to be to mow the patch. This can be done very efficiently with a mowing machine with the cutter bar tilted up in front only enough to prevent digging into the ground. Some growers dispose of the portion removed by burning over the patch. The mulch which is left between the rows is stirred up and with the leaves is allowed to dry. When in a good burning condition, fire is started on the windward side of the field on a windy day, the object being to burn over the patch quickly. Slow burning of piles of leaves or litter over the plants causes injury to the crowns. When there is difficulty in getting the fire to run well the leaves and litter may be raked between the rows and burned. Some growers rake up the leaves and coarse mulch with a horse rake and haul them off the plantation. Narrowing the rows is the second operation in renovation. This may be accomplished by plowing a furrow down either side of the row, throwing them away from the row, or by running twice between the rows with a two-horse cultivator. In this way the row may be cut down to the width desired, which usually is from eight to twelve inches. On heavy soils difficulty is sometimes experienced in plowing or cultivat- ing between rows because of the compactness of the soil due to tramp- ing during harvest. There seem to be only two things to do in such a case, irrigate or wait for rain. The narrowing of the rows should be followed by harrowing in the direction of the plowing and then across the rows. The beds may be gone over several times until the soil is in ideal condition. For this purpose, a spike-toothed harrow with teeth slanting back is preferable, although a weeder may be used with fairly good results. Fertilization may be accomplished at this time by distributing well- rotted manure over the rows and by cultivating or plowing in a liberal amount between the rows. A small application of nitrate of soda — one hundred pounds per acre — may be also applied to hasten new growth, but plants should not be allowed to become too thick. With the beds in this condition, cultural methods are the same as for the first year. 20 Wisconsin Bulletin 360 Strawberry Pests The common pests of the strawberry are the leaf-spot disease, the white grub, the strawberry leaf-roller, the strawberry aphis, and the weevil. All pests are most easily controlled when the location of the plantation is changed frequently. The leaf-spot, or strawberry blight, appears as round reddish- brown or purplish spots on the foliage. Usually it is not a serious pest. When it becomes troublesome it can be controlled by spraying with Bordeaux mixture. Usually an application just before blossoming will hold the disease in check. At times it may be desirable to make an ap- plication as soon as growth starts and also one immediately after blossoming. Cutting off and burning the old foliage is helpful on plantations to be fruited a second time. If the disease appears on the new growths an application of Bordeaux should be made. The white grub is frequently a serious pest of strawberries in Wis- consin. It attacks the plant just below the crown, severing the top from the roots. Its presence is first noticed by wilted plants which when picked up are free of roots. There is no very satisfactory remedy for this insect. Avoid newly plowed sod land. The adult leaf roller lays its eggs on the leaves early in the spring. The newly hatched larva feeds for a short time on the leaf, then draws the leaflet together with a silken thread and feeds upon the leaflet from within. Spray with three pounds of arsenate of lead to fifty gallons of water at the first appearance of rolling of the leaves. This may be followed by another application a week to ten days later. Mov- ing off and burning the leaves after harvest also aids in its control. A bed which is not to be fruited a second time should be plowed under im- mediately after harvest. The strawberry aphis or foot louse is a common pest in this state. As it works beneath the surface, it is not easily detected. Ants work- ing around the base of a weak plant are the best indication of the presence of this pest. The presence of ants does not always indicate that the plants are infested, nor are the ants always present where the aphis is to be found. The first attempt to control root aphis should be the taking of pre- cautions against infestation from outside sources. Persons securing stock from such sources should dip the plants just before setting, in an eight per cent kerosene emulsion or a solution of nicotine sulphate, one part to one thousand. The plants should be left in this solution ten to fifteen minutes. If the plantation is badly infested, little can be done to eradicate the pest and it is probably best to start a new plantation on another site. Burning over late in the fall is beneficial. The strawberry weevil is the least common of the pests mentioned This insect does its damage by puncturing the bud of perfect varieties Strawberry Culture In Wisconsin 21 and laying an egg in the interior. The flower stem is then partly cut in two so as to check further development of the bud. This cutting causes the buds to wilt and later to fall off. Where the insect is troublesome the planting should consist largely of imperfect varieties. Only enough perfect flowered plants to insure pollination should be set. The perfect flowered variety chosen should be a profuse bloomer. Cross -Pollination Is Important Several factors must be considered in the selection of varieties. It is quite as essential that sexual union take place for the production of a crop of berries as it is in securing offspring from animals. The strawberry plant is some- what peculiar in that different varieties produce different kinds of flowers. Some varieties, such as Senator Dunlap, have flowers bearing both male and female organs, and are there- fore capable of self-fertilization. Such varieties are known as perfect, staminate, or male varieties. The last two terms, however, are somewhat mislead- ing, for the flower possesses both stamens and pistils, and is there- fore not only a male but a female flower as well. Other varieties, such as War- field, have only the female or- gans present, and therefore can- not produce fruit without the presence of a stamen-bearing or perfect variety. Varieties having only the female sex organs are called imperfect, pistillate, or female varieties. We have no varieties of strawberries in which only the male organs, stamens, are present. If an imperfect variety is to be grown, care must be taken to select a perfect variety to be planted with it so as to provide for pollination. The first consideration is simultaneous flowering. If a variety is to act as a pollinizer of another, both must be in flower at the same time. In fact, it is desirable to have a perfect variety in which the blooming period is longer than that of the imperfect, so that the ripe pollen may be available at all times. The perfect variety should also produce a large amount of pollen. Varieties differ materially in this respect, but unless conditions are very favorable, shy pollen-pro- ducers will not give good pollination of imperfect varieties. This FIG. -TYPES OF FLOWERS Stamen-bearing flowers are necessary to fruit-production. Imperfect varieties must be accompanied by perfect. Left — perfect flower. Right- — imperfect. 22 Wisconsin Bulletin 360 ability to produce abundant pollen is one of the chief factors in mak- ing Senator Dunlap such a good pollinizer. Another requisite of a good pollinizer is its affinity for the im- perfect variety. Comparatively little is known about the pollen affinities of different varieties, but experimental work has shown that such relationships do exist. This is shown by the fact that two perfect varieties of seemingly equal pollination possibilities may give very different results when used to fertilize the same imperfect variety. Some varieties seem to be quite cosmopolitan in their affinities, and if their other characteristics are favorable, these varieties should be choosen for this purpose. Of the varieties showing this cosmopolitan tendency none of those tried have exceeded Senator Dunlap in general qualifications as a good pollinizing variety. It is commonly believed by growers that when perfect varieties are grown, it is not necessary to provide for cross fertilization. This is true, but investigation has shown that in most cases cross-fertilization gives better results than self-fertilization even with perfect varieties. For this reason it seems wise even when planting a perfect variety to use more than one variety. What proportion of the pollinizing variety should be used? Doubt- less much depends upon conditions. If the season is favorable for pollination or if bees are kept in the immediate vicinity, a smaller proportion of the pollinizer is necessary than if climatic conditions at flowering time were unfavorable, or pollen carriers scarce. One row of pollinizing plants to one of the variety to be pollinized is common, one to two is frequent, and one to three is sometimes used but is scarce- ly to be recommended. What Varieties Are Best? Frequently the question is asked : "What is the best variety of strawberry?" It is impossible to recommend any variety, or any two or three varieties, as the best, for no one variety does best under all con- ditions. It is equally true that certain varieties are more capable of adapting themselves to a greater range of conditions than are other varieties. As a result, these varieties are found growing over a wider range of territory and under more varying conditions than those less exacting in their requirements. It does not necessarily follow that such a variety will therefore be the best for any particular set of conditions ; on the other hand, there is a greater probability that some less cosmo- politan variety will be more profitable if the grower only has the patience to determine which variety best meets his conditions. Strawberries may be grouped into two classes, those which pro- duce their fruit during the early summer, and the "everbearing" or those which produce an early crop and later on another crop continu- ing until cold weather prevents further production. The former class Strawberry Culture In Wisconsin fc8 is far the more important at the present time, but the everbearing varieties are becoming more popular as they are improved. A study of varieties being grown in Wisconsin shows that regard- less of varying soil conditions practically the same varieties are used in all parts of the state. This v/ould indicate that these varieties are cosmopolitan and can be recommended as doing reasonably well under practically all conditions. A commercial grower should not be satisfied with average results. He should constantly be trying out a limited number of other varieties in comparison with the ones he is growing in an attempt to find, if possible, varieties which are better adapted to his conditions. It is some trouble and expense to run a trial plot for test- ing varieties, but it is quite likely to prove a paying investment. The following varieties are suggested as likely to prove reasonably satisfactory while tests are being made to find if possible those better adapted to particular conditions : Dunlap, Warfield, Glen Mary, Pocomoke, Aroma, Gandy, and Sample. These are named approximate- ly in the order of ripening. Dunlap is the most extensively grown strawberry in Wisconsin, both in home and commercial plantations. It seems to be well adapted to a wide range of conditions. It is a heavy plant maker. Care should be exeicised not to let it become too thick as production is reduced when this occurs. Warfield is an imperfect variety, mostly grown as a companion berry of Dunlap. It is a hardy variety but under most conditions not as productive as Dunlap, Glen Mary is partially imperfect and should be set with a pollinizer. It is a second early berry. A good producer but quite subject to spot. Pocomoke. This variety is also called Gibson. It is a mid-season variety. It is hardy and productive, and produces large fruit which ships well. Aroma. A large, high quality, attractive fruit which ships well. It is disease-resistant and productive. A good variety for producing a fancy product. Mid-season to late. Gandy. A good late variety. Not productive except on heavy, moist soils. Sample. One of the best late strawberries. Fruit large, attractive, and uniform. Ships only moderately well. It is imperfect, being com- monly pollinated with Dunlap. "Everbearing" Strawberries The "everbearing" variety most popular in Wisconsin is Pro- gressive. This variety is grown almost to the exclusion of other fall or everbearing varieties. Different varieties of the everbearers differ materially in the methods of handling. Owing to the popularity of Pro- gressive, directions will be given for growing that variety. 24 Wisconsin Bulletin 360 The soil should be rich, even more fertile than for the June bearing varieties. It must contain a large amount of organic matter as an abundant moisture supply during July, August and early September is absolutely necessary if a good fall crop is to be secured. Plant In Spring The plants should be set in the spring as soon as soil conditions will permit. The plants should be about 24 inches apart in the row and the rows 2>y 2 to 4 feet apart. These dimensions are for the matted row system, which most growers will find preferable. Take Off Early Blossoms For best results, the blossoms should be pinched off as soon as they appear until the early part of July. From that time on they may be left to produce fruit. Encourage the runners to root as readily as possible. A light mulch under the plants and frequent, shallow tillage between the rows are conducive to the largest production. Some system of artificial watering is very advantageous in growing the late crop, as frequently unless the best tillage and mulching is provided it is cut short by lack of moisture. How Long? Two crops are probably the maximum number to be taken from a plantation. Many growers take only the fall crop, as the spring crop is usually much lighter and the berries smaller. Must home growers, however, prefer to take a spring crop also. One of the reasons for this is that the everbearers ripen somewhat earlier than the June varieties. If the plantation is to be kept for a spring crop, it should be mulched during the winter as are the June varieties.