Recommendations for high-bush blueberry cultivation
Blueberry grow best in air- and water-permeable soils: sand, peat, peat-sand soil – light (not clay), but surely acidic soils.
Soil with pH range of 4.3-5.0, but not more than 5.5. That is why blueberry grows naturally in peatlands.
Blueberry grows on high and well-lighted areas. Set the blueberry transplants in a place free of cold wind. Blueberry grows well only in the sunlight, so choose a sunny place for the plant. In such places blueberries are sweeter and the bush is healthier.
The blueberry root system is located at a depth of 30 centimeters. Therefore, it is important to keep the soil constantly moist. At the same time, avoid long water stagnation, as lack of oxygen in the soil may cause plant death.
That is why do not overwater the blueberry and do not set it in places where water stagnates. The ground water level should be at a depth of 60-80 centimeters.
It is better to set blueberry on a hill or drain on heavy clay soils and at high location to the ground water surface.
Before planting, dip the transplants in a container with water up to complete water saturation of the root ball. Also before planting, spread the roots and release from the container in which the blueberry bush was growing! (This recommendation applies primarily to blueberry transplants older than 3 years).
Dig a planting hole of 40-50 centimeters depth, with a diameter of 0.7-1.0 meters. Fill the hole with substrate, which consists of 50% of the dug-out earth and 40-50% of pine needles or moss/non-deoxidized peat (it is lighter than the lowland one and is almost red), and add 5-10% of pine bark. Leave a space of 5-8 centimeters between the edges of the hole when filling the hole with substrate. Set the bush in the center of the hole. Fill the remaining 5-8 centimeters with mulch.
You can use softwood soil instead of peat (only the composed layer). Do not add needles, moss and strobiles to the hole. If you have reached the sand in the woods with your shovel, then do not take the soil from this place for planting blueberry.
Set 2-or 3-year old transplants with well-developed root system at any time of the growing season, provided that blueberry grew in a container. The distance between bushes should be 1.0-1.5 meters.
The soil surface around the bush should be mulched with a layer of pine sawdust 8-10 cm deep. The blueberry can be mulched with straw, composed leaves, pine needles, peat, ground bark, wood chips and hay. Sawdust will be the best choice, because it compacts slower and decomposes longer. The optimum blueberry planting time:
bareroot – in the spring before the bud break or in the fall after the end of the growing season;
with a closed root system (in containers – usually blueberry transplants are sold with a closed root system) – during the whole growing season.
Requirements for planting:
– transplants are dipped in a container with water up to complete water saturation of the root ball;
– plants are released from the container;
– roots are spread;
– root crown is buried under 3 cm of earth;
– the soil around transplants is firmed and abundantly watered. Distance between rows – 3.0-3.5 meters.
Distance between plants: for early-season cultivars/varieties – 1.0 m; for mid-season – 1.3 m; for late-season – 1.5 m.
– maintain soil moisture longer
– protect the soil from rapid changes of night and day temperatures: mulch prevents soil overheating during the day and does not allow it to cool quickly during the night
– reduce the number of weeds
– buds come out later in the spring and leaves fall off slowly in the autumn. This helps blueberry withstand temperature fluctuations
– rapid aftergrowing and uniform ripening of shoots
– protect of the root system in the winter time
– healthy develop a blueberry bush, as the disease-producing fungus, wintering on fallen leaves, dies without hitting the ground because of the sawdust (mulch) layer
– blueberry transplants feeding since the decomposed sawdust (mulch) becomes food for the plant.
During the first years blueberry bushes should be protected from severe frost. Blueberry withstands spring cooling. For frost protection bind the blueberry with spruce branches, cover with spunbond, frost cloth or burlap, but do not use polythene film.
A blueberry bush can grow and berry annually up to 40 years in one place, 7-10 kg of berries.
Attention! Blueberry needs no organic fertilizer (manure, humus, chicken manure, compost, etc.). Only mineral fertilizers are required:
50-60 grams of superphosphate, 15-35 grams of magnesium and 1-2 grams of micronutrient mixture per bush are required for the plant development. Blueberry, like no other berry crop, needs nitrogen. Leaf yellowing, shoot growth cessation, berry size reducing are cause by nitrogen deficiency.
Nitrogen is applied in three stages: 40% – during budbreak, 35% – in early May and 25% – in early June.
Phosphorus is applied in the form of simple superphosphate (50-60 grams per plant) and double superphosphate (25-30 grams per plant) at 5-10 cm deep.
Potassium is required for a fair yield. Potassium chloride is toxic to blueberry plant, that is why 30-45 grams of potassium sulfate is applied per bush.
The best forms of mineral fertilizers for dressing: ammonium sulfate, potassium sulfate, magnesium sulfate, zinc sulfate and superphosphate.
When using fresh sawdust as mulch, increase the nitrogen fertilizer rate 2 times, because sawdust absorbs nitrogen, required for blueberry bushes growth, when decomposing.
It is better to use special fertilizers recommended for heath plants – buy fertilizers for blueberry in Belarus.
The water used for watering should be acidic, i.e. 4 to 5 pH. However, usually water pH is higher, therefore, it is recommended to acidify the water: 0.2- or 0.3%- table vinegar, citric acid or oxalic acid in the amount of 1 teaspoon per 10 liters of water, or 9%-acetic acid and malic acid in the amount of 100 grams per 10 liters.
No watering with acidic water is required, if the bush is mulched with pine sawdust.
Good watering is very important in August, when blueberry yields and sets flower buds of the further yield.
Blueberry is affected by monilial blight of shoots, stem cancer, decorticosis of branches, shoot apex drying, blueberry blossom blight. For prevention treat (spraying) blueberry bushes with fungicides twice a year before the berry-bud formation and after the harvest.
Gray mold can appear during humid weather. Vigorous thinning of bushes is used for prevention.
Treat blueberry bushes with copper-bearing preparations for winter:
– Copper oxychloride, kuprozan.
For amateur cultivation do not use chemicals against pests – insecticides, because blueberry has only a few pests and their presence does not affect the bush growth and further yield quality. Collect by hand the destructive insects.
Spray blueberry plants with fungicides (topsin, euparen) to prevent disease after the spring pruning.
gypsy moth, cowberry moth, black vaccenic aphid, scale insects and grub worms.
Blueberry is pruned in early spring (March, early April). Old shoots should be always replaced by new ones. Therefore, blueberry should be polled starting from 3-4 years of age. Blueberry is pruned in early spring when no buds have blossomed, or in autumn after the leaf fall. Remove all diseased branches and branches lying on the ground. No more than five annual shoots should remain. The first pruning begins no earlier than in 6-7 years!
Young plants are cleaned off shoots injured by frost and those which are low-lying, growing along the ground.
When blueberry bush reaches 4 years of age, bush thinning is required to enhance its growth and ensure continuous yield.
Thinning accelerates the emergence of strong one-year-old shoots and ensures regular yield.
Remove the old shoots (4-5 years) and measure the number of young ones when thinning blueberry bushes. Young shoots with lots of flower buds should be cut by a third. Flowers are removed from blueberry bushes during the first year after planting. This is done in order to affect the proper development of plants.
Young blueberry bushes should be pruned stronger, because this initiates the plant growth.
The maximum yield of blueberry bushes is achieved during the 5-6th year after planting in the garden.
The oldest shoots are cut from berry-bearing bushes for crown thinning. Remove all diseased, injured and highly branched shoots at the bottom of the bush. Blueberry bushes should not be too thick. Shoots which are no older than 4 years should prevail.
Different type of pruning is performed depending on blueberry cultivar/variety:
– pruning of long shoots of fast-growing varieties bushes that grow along the ground.
– densely tillered varieties are fully pruned; it is necessary to clean off carefully the bush bottom from all small shoots.
– blueberry varieties with more elongated structure should be pruned stronger, thus initiating their growth. It is necessary to prune the shoots and branching inward the bush, thus releasing the crown from thickening.
– blueberry varieties with dense structure should be shortened by too branched shoots.
– thinning crown is required for blueberry varieties that provide high yield with a lot of shoots.