Soil and growing site
Strawberries grow best in an open, sunny location. The best soil for strawberries is fertile, loose, permeable to moisture, slightly acidic or neutral (pH 5.8-6.5), humus-rich sandy loams and loams, where the water table is not less than 0.7 m from the surface. Very acid soils should be limed at least one year before strawberry planting. It is not suitable to plant in dips in the ground where water pools in the spring, where the strawberries get waterlogged and the berries rot badly.
Prior plantings and crop rotation
Strawberries can be grown in the same location after beetroot, carrots, radishes and lettuce. It is not suitable to plant strawberries in the same location after flowers, seed plants, beans, tomatoes, cucumbers, potatoes and other plants that leave large residues (late cabbage, corn, gladiolus). Strawberries can be planted in the same place after 3-4 years.
Soil that has been used for strawberries for several years is prone to weeds, especially perennial weeds, and specific disease-causing parasites. Strawberries also absorb the nutrients they need from the soil over several years. They should be followed by a short-growing fodder crop, oilseed radish (a cover crop), which is then ploughed up in the autumn, followed by winter rye, which is ploughed up in the spring. It is suitable to sow marigolds and dill. Short-growing crops can be sown 2 times a year. This helps to kill weeds, increases organic matter and improves soil structure.
By following proper crop rotation, strawberries will grow up healthy and will very rarely need to be ‘treated’ with fungicides.
Soil preparation
The soil is levelled, loosened, ploughed (or turned over with a shovel if the area is small), perennial weeds are removed, and before planting, a non-chlorine complex fertiliser low in nitrogen and higher in phosphorus and potassium, with trace elements, is applied. Very little additional fertiliser will be needed thereafter. Fertiliser must not be overused, as the plants are particularly sensitive to nitrogen fertiliser. Strawberries that are over-fertilised produce foliage that is too lush, become very dense, lose their resistance to disease and have more rotting berries.
Planting time
Strawberries are planted in the second half of April (sometimes in early May, depending on weather and soil moisture) or in mid-August. Only healthy seedlings with three leaves are planted, slightly deeper than they were in the nursery, in moist soil and then watered. To help the seedlings to establish themselves, before planting, the roots of the seedlings are soaked in a paste of clay and manure (the consistency of sour cream).
After planting, the plants are mulched with peat or a mulch of shredded tree bark to help them to establish themselves more quickly and to reduce weed growth. Straw mulch keeps the berries clean and reduces weed growth. For earlier ripening, mulching the beds (or a larger area planted in rows) with black agro textile will also reduce weeds.
Planting distances
Seedlings are planted in rows (0.8 × 0.3-0.4 m), or at greater distances for the strawberry varieties ‘Dukat’, ‘Venta’, ‘Senga Sengana’, which are prone to rotting and tend to be more bushy, or in strips (0.5 × 0.3 m), or in a carpet pattern (1.0 × 0.5 m). All the seedlings that grow from the runners are allowed to take root (suitable for ‘Honeoye’).
Applying fertiliser to strawberry plants
Fertiliser is applied 2-3 times per season. Young strawberry plants receive fertiliser when 1-2 young leaves have emerged at the end of April – the first days of May and in mid-June, using a complex fertiliser with trace elements (10-10-20 or 8-12-23) at a rate of 4 kg/are, if no fertiliser was applied prior to planting, and only a small amount of additional fertiliser if it was applied prior to planting.
Producing strawberry plants receive fertiliser in early spring and mid-June, using a complex fertiliser (10-10-20 or 8-12-23) at a rate of 6 kg per are.
In case of frost danger, strawberries are sprayed in the evening with 0.2% Fainal potassium solution (2 l/ha), then the sprayed plants are not damaged by frost.
Strawberries are sprayed 1-2 times over the leaves with a 0.2% Boramin Ca solution when the flower buds form, during flowering, and before producing berries. This solution helps to increase the number of buds, increases pollen activity and ensures berry quality. After harvesting, the strawberries receive a complex fertiliser with trace elements at a rate of 4 to 6 kg per are.
Strawberries are sprayed for protection against various rots with Signum fungicide at a rate of 0.4 l/ha. It can be applied both during flowering and at the beginning of berry production, because it has a withdrawal period of only 3 days.
Care and treatment
Weeds are controlled by loosening the soil between the rows, weeding, mulching or spraying herbicides (if large areas are cultivated). Young strawberry plants are sprayed one week after planting with 1.5 l/ha of Betanal Progress AM (controls annual dicotyledonous weeds), followed by 0.35 kg/ha of Lontrel (controls perennial weeds such as dandelion, field milk thistle, chamomile).
In early spring or after harvesting, 2-3 l/ha of Betanal Progress AM is sprayed on producing strawberry plants, followed by 0.5 kg/ha of Lontrel.
After harvesting, the strawberry stems should grow new, lush foliage, and it is not necessary to cut the old leaves. Leaves should only be cut in diseased, pest-infested and weedy strawberry patches. Cut immediately after harvesting at least 5 cm above the sprouts. All other strawberry care is done after the leaves have been cut.
As the berries ripen, the strawberry stems hardly grow at all. After harvesting, new leaves, runners, roots and later new sprouts start to grow intensively. The stems grow intensively from mid-July to the end of August. Strawberries then need additional fertiliser and watering. After that, growth slows down and the formation of flower buds begins, which continues until the end of the growing season and the following spring. If watering and application of fertiliser are begun later, there is less time for bud formation and the following year’s yield will be lower.
Watering
Strawberry roots grow on the surface of the soil, which makes the plants sensitive to lack of moisture and therefore need to be watered. Water 1-2 times before flowering, 2-3 times when the berries are growing and 1-2 times after harvesting. The strawberry plants are watered in the evening or at night to allow the plants to dry out during the day and to prevent rotting.