The Strawberry is our most widely cultivated small fruit. In suitable varieties it is grown in every state, much of Canada, except the coldest regions, and even in the milder parts of Alaska. It is grown extensively commercially in widely separated parts of the United States and Canada and is the most popular and easily grown garden fruit.
The common cultivated Strawberry, Fragaria chiloensis variety ananassa, is descended from the wild species, F. chiloensis, of the Pacific coasts of North and South America, and F. virginiana, a native of eastern North America. These were taken to Europe by early travelers, where they soon became hybridized, and some of the resulting varieties were returned to North America. From them, other varieties, especially suitable for culture in the United States and Canada, were developed, and commercial planting started about the year 1800. A rapid expansion of Strawberry planting took place after the Civil War, when varieties having fruits suitable for shipping became available.
The Strawberry is suited to a wider range of climatic conditions than any other Temperate Zone fruit. Over the years varieties have been developed for such extremes as are found in Florida, with its hot, humid climate and short summer days, and the prairie provinces of Canada, with their long, hot, dry summer days and cold winters, often without much snow cover. There are even varieties that will stand the winters of Wyoming without protection. The Strawberry, with its many varieties, is a very adaptable plant.
Varieties of the common Strawberry are classified as June-bearing and everbearing, according to whether they produce one crop of fruit (in June in the North, earlier in the year in the South) each year and no more, or bear a succession of fruits from late July or August until frost. The June-fruiting varieties are divided into early varieties and late varieties, there being a week or more difference between the dates of ripening of these kinds. In addition to varieties of the common Strawberry, other kinds called Alpine and Hautbois Strawberries are sometimes cultivated.
Soil and Site. Strawberries will grow on a wide range of soils, provided the plants are in good physical condition and are managed properly. Soil texture, if not extreme, is secondary in importance to good drainage, freedom from soil-borne diseases, a satisfactory moisture supply, sufficient organic matter in the soil and freedom from perennial weeds. The ideal soil is a deep, sandy or gravelly loam, overlying a subsoil that is retentive of moisture but is well-drained. Coarse sands and gravels are subject to drought and compact clay soils are poorly drained and difficult to manage; for these reasons they are less satisfactory.
A soil well-supplied with organic matter is not only less subject to drought, but also is easily worked, and its mellow condition is favorable for the rooting of the Strawberry runners.
Good drainage, surface as well as internal, is important because Strawberry roots are easily injured if the soil is saturated. Soils that are nearly saturated in winter heave readily, causing damage to the roots. The red stele root rot disease is a disease of poorly drained soils. A gentle slope and a porous subsoil favor good drainage.
In gardens where Tomatoes, Potatoes, Peppers and Eggplants are grown, the crop rotation should be planned so that Strawberries will not be planted on land which has grown these crops within the previous 3 years. These crops may infect the soil with verticillium wilt, a troublesome root disease of Strawberries.
Good air circulation is desirable as a partial protection against frost, which is usually worse in low spots surrounded by higher ground. Fungus diseases of the foliage are less severe where there is good air movement, as on a slope. The direction of the slope influences the time of ripening of the fruits. Strawberries on a south-facing slope ripen several days earlier than those on a north-facing slope. This difference should be considered, as it may give one an advantage on early or late markets or of a longer season of home picking if early varieties are planted on a south slope and late varieties on a north slope. Strawberries require a sunny location.
Preparation for planting depends upon the previous management of the soil for several years. Organic matter in quantity is desirable and may be supplied by the generous application of rich compost, or by the addition of stable manure at the rate of about 20 tons to the acre; this amount may be increased or decreased, according to the needs of the soil and the supply of manure.
If manure or rich compost in sufficient amounts is not to be had, then the soil should be managed so that the ground is occupied by a grass, or legume sod, preferably the latter, for at least two years before the Strawberries are planted. The sod crop should be heavily fertilized to stimulate the production of as much plant material as possible to be plowed under in preparation for the Strawberries. A hoed crop should be grown for one year before the Strawberries are planted.
Many growers fertilize their fields with a complete fertilizer such as a 5-10-5 at the rate of 1,000 pounds to the acre when making the land ready for planting; or they apply the same amount as a dressing sprinkled alongside the rows of plants at the first hoeing after the plants are set out. A fertilizer supplying nitrogen alone at this time would probably be sufficient in most good soils.
The land should be plowed in the fall if possible, but spring plowing is satisfactory on light soils that permit early working. The making ready of the soil should be as thorough as for vegetables. Strawberry plants are set out more easily, and start better in a loose, mellow soil that is free from lumps.
Strawberries are usually planted in early spring as soon as the soil can be had in suitable condition. Late planting, if followed by hot, dry weather, may result in a poor stand of plants. Late fall planting, even in late October or early November, is successful if the plants are well-mulched before severe weather arrives. The mulch must be removed in the spring and the planting managed like a spring-planted bed. The principal advantage of fall planting is the early start the plants get in the spring.
The plants to be set out should be purchased from nurseries specializing in the production of Strawberry plants. Virus-free plants should be specified, as these are much superior to the older stocks, which are often virus-infected and do not grow vigorously.
The young plants should have vigorous roots, straw-colored or nearly white and fibrous. Plants with black and sparse roots are not suitable for planting.
Cold-storage plants are being used for planting in increasing numbers. These come mostly from Maryland, where they are dug during the winter while fully dormant and are kept in cold storage at a temperature of about 32 degrees F. until the shipping season. These plants, because they are fully dormant at planting time, prove superior to plants that are dug after growth has started.
When the plants are received from the nursery the bundle should be opened and the plants heeled in (planted temporarily) in a shallow trench in a moist, shady place until they are to be permanently planted. If they are dry on arrival, the roots should be soaked in water for an hour.
Planting Systems. Strawberries may be grown in matted rows or in hills. With the matted row system all of the runner plants that develop are usually allowed to grow and the result is most often an overcrowded fruiting row. Much better results are secured if many of the runners are eliminated so that the plants are spaced at the best distance for maximum production. If the runner plants in a matted row system are spaced about the mother plants about 6-8 in. apart until the row is filled out to a width of 18 in. and all later runners are removed, overcrowding is prevented and superior results obtained. The spacing is done when the bed is hoed.
When the plants are grown in hills, all of the runners are removed as they appear, leaving only the plants that were planted to produce the crop. The hill system usually produces the best fruits, but because the plants are set more closely together at planting time the costs for plants are higher.
Strawberries planted to produce a matted row bed are usually set 1 1/2-2 1/2 ft. apart in the row, depending on the runner-making ability of the variety and the fertility of the soil. The distance between the rows is 3-3 1/2 ft.
In the hill system the plants are set 1-11/2 ft. apart in the row and 2-3 ft. between rows. Sometimes they are set in beds of 2 or 3 rows with an alley between for the pickers. A variation of this is to set the plants in hills and allow a runner to take root in the row, on each side of the mother plant, or sometimes on each side of the row to make a triple row. The essential thing, whatever system is followed, is to prevent the excessive crowding that often results when too many runners are allowed to take root and establish themselves.
Method of Planting. The plants may be set out with a trowel, or with a spade. The spade requires two persons. One inserts the spade in the soil vertically and pushes it back and forth to make a V-shaped hole into which the roots are placed, spread apart and not crowded together in a lump. The top of the crown of the Strawberry plant should be even with the surface of the ground. As the spade is removed, the soil should be firmed about the roots by pressing it with the foot. A properly set plant should resist a strong tug without becoming loosened in the soil. During planting, the roots should not be allowed to dry out.
Removing Blossoms. Amateur gardeners are often so anxious to obtain fruits from the Strawberry plants they set out that they permit them to bear fruit the first season. This is a mistake. The plants should not be allowed to fruit until their second season; all blossoms should be removed the first year to prevent fruiting. Plants that fruit the first year are not able to make a good start at becoming well established.
Controlling weeds is the principal job during the growing season. The field should be cultivated and hoed often enough to eliminate all weeds while they are yet small. They are much easier to control while small and it is important to eradicate them before they have competed with the Strawberries for nutrients and moisture.
Chemical weed control is used by some growers and if it is done properly it can greatly reduce the number of cultivations needed. Special herbicides (weed killers) that kill germinating weed seeds may be used. These weed killers, such as Crag No. 1, are not effective on seedlings over a quarter inch in height. To use them effectively the field is cultivated and hoed to eliminate all sizable weeds, and is then sprayed with the herbicide in dilutions recommended by the manufacturer. For a few weeks the herbicide kills the germinating weed seeds, then loses its effectiveness, and the process is repeated. It does not injure the plants, but may stunt the roots temporarily as they begin to develop on the runner plants.
Weed killers containing 2,4-D may be used to control broad-leaved weeds, but this material is not effective on grasses. It should not be used later than mid-August, as it affects the fruit buds which develop after that, and many misshapen berries will result the following spring. It should not be used in the spring of the bearing year. 2,4-D is useful for cleaning up the weeds in a bed that is being renewed after harvest.
Other weed killers are sometimes used. The dinitro compounds are effective on Chickweed if properly used. New materials are being developed rapidly and Strawberry growers should secure the latest information on chemical weed killers from their State Agricultural Experiment Stations.
Geese have also been used to weed Strawberries. They do not eat Strawberry leaves and they do eat grasses and some, but not all, broad-leaved weeds. Young geese are better weeders than old geese and they must get the weeds while these are small as they do not do a good job on old weeds. The geese must be confined with a 30-inch fence, and water, some feed, and shade are necessary. These should be at least 25 feet from the Strawberries to prevent excessive trampling by the geese.
The Strawberry bed usually needs one weeding in the spring of the fruiting year. Unless this is done, it will be very weedy by the time the berries are ripe and the competition between the weeds and the berries for moisture will reduce the crop.
Irrigation is usually a profitable practice in growing Strawberries. The plants are shallow-rooted, with the bulk of the roots in the top 6 in. of the soil, and the effects of dry weather are soon felt. The crop may be reduced one half or more by a water shortage when the berries are ripening. Strawberries need about an inch of rain a week and any deficiency should be made up by irrigation if a water supply is available. Portable pipe and revolving sprinklers are used on large plantings. In the garden, porous canvas hose (soil-soaker) is used.
The fertilizer requirements of Strawberries have been the subject of much experimentation, but the results are less clear-cut than with many other crops. Nitrogen is most apt to bring profitable results; and late summer and early fall applications when the fruit buds are being formed have sometimes resulted in increased yields. Nitrogen applied in the spring of the bearing year usually decreases yields and may result in soft berries and much rot in a wet season.
The phosphorus and potash requirements of Strawberries are usually met in most soils suitable for Strawberry growing. In the home garden there is no harm in using these elements in a complete fertilizer. On infertile soils complete fertilizers may be used. Strawberry growers should recognize that water, early planting, spacing of runner plants, winter mulching, weed control and the control of diseases and insects are much more effective in increasing yields than are fertilizers.
The best practice is probably to apply nitrogen in mid-August at the rate of 50-60 pounds per acre. This may be obtained by using 150-200 pounds of ammonium nitrate or twice as much nitrate of soda. Other materials that furnish the same amount of nitrogen may be used. The fertilizer is broadcast over the plants when dry and then brushed off with a broom, or piece of brush, to avoid burning the foliage.
Harvesting. The berries should be picked every other day because they are highly perishable. The pickers should handle them carefully to avoid bruising. As soon as possible the filled baskets should be removed to the shade or a cool cellar. After harvest, the bed, if not too weedy and if in good vigor, may be renewed for another crop the following season. This is done by removing the tops (cutting off the old foliage), cleaning out the weeds, and fertilizing the bed. Some growers plow out the plants along the side of the row and renew it with the runner plants that grow in late summer from the center plants, but beds so renewed may be less productive than those where all the plants are left, if the row is not too crowded.
Winter Protection. Strawberries should be mulched for winter protection. The crowns and roots of the plants, if unprotected, are often severely injured by low winter temperatures. This injury appears the following spring and is evidenced by reduced growth, reddened foliage, and eventually, when the berries are ripening, by the wilting and collapse of the plants.
To prevent this injury the mulch should be applied before temperatures drop below 20 degrees F., but after two or three hard frosts have occurred. The plants should be covered to a depth of 2-3 in. with the mulch.
Wheat straw and marsh hay are excellent mulching materials. Rye and oat straws are also good. Leaves and sawdust are sometimes used if better materials are not available. Pine needles are much used in the South.
In the spring, part of the mulch is raked off the plants into the alley between the rows. The leaves and flower clusters push up through the thin covering of straw which is left to keep the berries clean, to conserve moisture and to check weed growth quickly to a considerable extent.
Propagation. The Strawberry may be propagated from seeds or by the division of plants in early spring, but by far the easiest and best way is by young plants formed on runners. Runners are slender, trailing stems which develop from the bases of mature plants in July. For the best results propagation should be done from parent plants which have not been allowed to fruit the year the young plants are taken.
The parent plants should be the most vigorous, disease-free plants with good flower trusses in their first year. Runners which fail to produce a flower truss in their first year should always be removed and destroyed. Having selected the parent plants, the next thing is to concentrate their energies into vegetative production. The flower stalks should be cut and no flowering or fruiting allowed. The plants may be marked ones in the ordinary bed or given a small nursery bed of their own. They should be hoed, fertilized and well watered.
Layering Runners. In July, the runners will form and should be restricted to four to six per plant. The runners should be trained to root either in 3-in. pots, filled with good soil, or in a prepared bed of equal parts, by bulk, loam and compost (or peat), liberally enriched with bone meal, between two boards or rows of bricks by the sides of the parent plants. Small plantlets form where the runners rest on the soil, and this can be encouraged by pegging the runners down, where the plantlets are rooting, in the pots or bed. Once the plantlets are growing and rooting, the free end of the runner should be cut at 2-3 inches beyond, but leaving the basal end still attached to the parent plant. Although more than one plantlet can be formed by a single runner, it is wise to propagate only one plantlet per runner in the interests of getting first-class stock, fully characteristic of the parent strain.
The young plantlets should be kept watered in dry weather, and an occasional feeding with a liquid fertilizer is helpful. In four to five weeks, the young plants are usually ready to be severed from the patent plant, and can be transplanted for the making of new beds, or grown on for forcing under glass. The parent plants may be allowed to grow on for fruiting, but should not be used for propagation again.
All this may seem a counsel of perfection, and many gardeners are tempted to propagate from their fruiting plants rooted with or without their attention in the ordinary soil. This may succeed for a few seasons, but in time is usually attended by a perceptible falling off in the performance of the plants and their fruiting vigor.
Strawberries from Seeds. Strawberries do not come true to variety from seeds, and seed-raising is chiefly of interest to the hybridist or those interested in raising Alpine and Hautbois Strawberries. The seeds are located on the outsides of the fruits and are separated by crushing, washing and drying fully ripe fruits. They should be sown very shallowly in pans or flats in a cold frame or greenhouse in March or in light soil out of doors in early spring. The plants are later transplanted to the beds where they are to grow and produce their fruits.
Growing Everbearing Varieties. The everbearing varieties of Strawberry require special treatment, as they produce very light crops when grown in the same way as the June-bearing varieties. They are less vigorous and produce fewer runners.
The soil should be highly fertile from the addition of stable manure or compost or commercial fertilizer, and irrigation will be necessary, as the berries ripen if the weather is dry. Growers in Ohio have developed a method of growing the everbearing varieties in hills under a sawdust mulch. The plants are set out in the spring in hills, cultivated a few weeks and then mulched with an inch of sawdust all over the field. All runners are removed as soon as they appear. The blossoms are picked off until early July, after which they are left on the plants and the berries begin ripening a month later, continuing until frost. The costs of growing the everbearers by this method are high, but the returns from out-of-season Strawberries are also high if a market is available at luxury prices.
Strawberry-growing in Barrels. Strawberries may be grown in pots or boxes on window sills, and a good method for limited space is to grow them in a barrel. A sound, clean barrel is prepared by drilling with 1-in. drainage holes, 6 in. apart, in the bottom, and with rows of 21/2-in. holes in the sides, about 12 in. apart, staggered so that the holes of one row lie between those of adjacent rows. The barrel is stood on bricks, and a 2-in. layer of broken bricks, stone or rubble placed in the bottom. A 6-in. drainpipe of earthenware, stout cardboard, or tile is placed centrally, filled with broken brick, and the barrel then filled with a rich soil mixture, such as equal parts by bulk of good loam and rotted manure or compost, plus 6 oz. bone meal per bushel. The soil should be well firmed as it is put in, and the young plants inserted in the holes as filling proceeds. The center pipe is lifted out to leave a core of porous brick, and half a dozen plants can be set on top of the barrel when filled.
The barrel should stand in a well-sunned but sheltered place, and may be watered through the central core. It is usually necessary to replace the plants annually, and only first-class stock should be used.
Varieties of Strawberries are very numerous and many are rather local in their suitability for different latitudes and soils. The varieties suited to New York are wholly unsuitable for Tennessee, Louisiana, California and other regions where conditions are very different from those where the varieties originated.
The varieties favored for planting are changing rapidly as many new ones are being developed by the experiment stations. Prospective planters should inquire of their State Agricultural Experiment Stations, or of their Strawberry-growing neighbors for information regarding the best varieties for local conditions. The catalogues of Strawberry nurseries offer the varieties currently in favor. The following are the better and more widely grown sorts at present.
For the northern states westward to the Mississippi valley, the principal varieties are Howard (Premier), Catskill, Sparkle, Temple, Fairland, Robinson, Fairfax, and Pathfinder. New and promising are the varieties Empire, Erie, Eden, Vermilion, and Armore. For the upper Mississippi valley Beaver and Senator Dunlap are among the hardiest.
For Washington, D. C., to the Carolinas, the varieties Blakemore, Klondike, Massey and Suwannee are recommended, the latter being a high-quality variety for home use. Dixieland and Pocahontas are new and promising for trial in this region.
For Kentucky and Tennessee, the varieties Tennessee Beauty, Tennessee Shipper and Aroma are important. In the Gulf coast states, Missionary, Blakemore, Klonmore and Klondike are important. These same kinds as well as the variety Ranger are suitable for Texas.
For Florida the recommended varieties are Florida Ninety and Missionary.
For the Pacific Northwest the varieties Marshall, Brightmore, Corvallis and Northwest are recommended.
Varieties suitable for cultivation in California are Marshall and several that were developed there, Shasta, Donner, Tahoe, Lassen and Sierra.
The everbearing varieties Gem, Superfection and Brilliant are all very similar, if not identical, and are good. Streamliner and Twentieth Century are other everbearing varieties worth growing.
For Canada the following varieties are recommended: In Alberta, British Sovereign, Senator Dunlap, Premier, Borden; in British Columbia, British Sovereign, Marshall, Senator Dunlap, Magoon; in Manitoba, Senator Dunlap, Glen-more; in New Brunswick, Premier, Senator Dunlap, Catskill, Mackenzie; for Nova Scotia, Premier, Senator Dunlap, Catskill, Pathfinder; for Prince Edward Island, Senator Dunlap, Borden, Crimson Glow; for Quebec, Premier, Mackenzie, Senator Dunlap, Catskill, King; for Saskatchewan, Senator Dunlap, Dakota, Prairie Bell.
Alpine and Hautbois Strawberries are quite distinct from varieties of the common Strawberry. They represent species native to Europe. The Alpine kinds are derived from Fragaria vesca variety semperflorens; the Hautbois Strawberry is F. moschata. All bear small berries of delicious flavor over a long period during summer and fall.
These kinds of Strawberries are usually propagated by seeds sown in spring. The young plants are transplanted to flats of fertile, porous soil and later to outdoor beds or are planted as edgings or borders to paths. Most varieties should be spaced about 12 in. apart, but one of the best and most commonly available, the Alpine Strawberry Baron Solemacher, needs 18 in. between individuals. Baron Solemacher is a vigorous grower; it does not form runners. The Alpine variety Cresta is a good runner-forming kind. Fragaria vesca variety variegata has leaves handsomely variegated with white.