High-bush Blueberry Growing Tips
Soil requirements. Blueberries prefer acidic (pH 3.5-5.5), free-draining yet moist (irrigation!) soils with low salinity. They can be sandy, sandy-clayey, with plenty of rich organic matter or peaty but always with loose structure, well aerated and permeable. Blueberries develop shallow and delicate root system and that is why they require moist substrate and a good supply of nutrients. It is important that the highest level of groundwater (e.g. during the spring melt or rainfall in July) remain beyond their roots reach and that is why some plantations should be well drained before planting to regulate water relations in the substrate. Blueberries demand both regular water and air supply for their healthy growth and abundant cropping. The acidity of the soil can be lowered by adding wettable sulphur chips or dust.
Planting. It is ideal to plant blueberries in the north and south facing rows. The distance between rows should be 2.5-3.0 m and the spacing between bushes in rows should be 0.8-1.8 m (2,000-5,000 shrubs/ha). When replanting blueberries onto the plantation it is good to use the seedlings which were grown in containers since they develop faster and better. In soils lacking in humus, it is best to put some sour peat into the planting holes (10 l per planting hole, and in poor soils with small humus content that dose should be even several times greater), mix it well with the “local” soil and then plant the seedlings. The substrate in the planting holes should never be enriched with fertilizers.
Fruiting. Blueberries are insect-pollinated plants, especially bees and bumblebees are reported to be responsible for the pollination (three to four bee families are enough to effectively pollinate 1ha of plantation). Pollination by insects is advisable since it affects a more abundant and ripe cropping of blueberries. A required maturity date and other features vital for the blueberry grower (destination market, fruit size, transport tolerance, shelf life, regular fruiting, harvesting type, etc) should be the basic criteria for selecting the best cultivars. For example, the Berkley variety gives a crop of up to 20 t/ha in Germany, but in Poland it yields only up to 10 t/ha. Due to a strong demand for fresh fruits on the market, it is good to plant such blueberry cultivars which crop at different times. Then their harvesting can be facilitated and their sale period extended. In Germany, ten pickers are estimated to be needed per 1ha of the blueberry plantation during its harvesting time. On big plantations, mechanical harvesting is used; some varieties, especially the Rubel and Bluejay are good for mechanical harvesting.
Fertilization and plant protection. Detailed data on fertilization and plant protection should be looked for in thorough studies on blueberries. The soil under the bushes can be mulched (e.g. with woodchips or sawdust) to regulate the level of moisture in the substrate; it will also provide additional amount of humus. Mulching with woodchips or sawdust is beneficial for the soil, but it also entails amending it with a greater dose of mineral fertilizers – in the case of nitrogen even twice more – since decomposing bacteria can rob plants of necessary nitrogen and thus they may suffer nitrogen deficiency. All additional data on rigorous fertilization of blueberries can be found in specialist literature. Proper fertilization of blueberries (taking into account their specific and low nutritional demand) should be grounded on detailed recommendations resulting from the analysis of the substrate or their leaves, and take into account the season of the year, the age of the plantation, the habitat conditions, etc. One should also bear in mind that the annual dose of fertilizers ought to be divided into three parts and the dressing of the soil needs to be carried out in appropriate time. In some regions, growers protect their plantations against winds by planting rows of trees in such a way that they do not compete with blueberries for the sunlight and water (varieties developing roots deeply, e.g. alder or pine trees are recommended). Dividing the plantation into several quarters by means of rows of trees helps to create favourable microclimate for the blueberry cultivation. It not only provides protection against winds and thus prevents its bushes from moving their sprouts abruptly, which could results in rubbing out the pruinose coating from their berries and in lowering their commercial value, but it also prevents the fruits from being shaken off. Despite the fact that blueberries are rather resistant to pests and diseases, more and more frequently they require protection against them. One should always remember that prevention plays here an extremely important role.
Pruning. In the first years after planting, blueberries do not need shaping – only sanitary pruning is needed. When blueberries are several years old they should be regularly pruned in autumn, after their leaves fell off, following the below-mentioned tips:
• make all cutting using a pair of strong and sharp two-handed shears; on greater plantations rather pneumatic pruners should be used
• cut out all dead or broken branches
• remove all thin, drooping to the ground or horizontally developed branches, or the ones which obstruct movement in the spacing between rows since they make harvesting more difficult and they always bear worse quality fruits
• remove all branches older than five years in order to constantly stimulate bushes to develop new and healthy sprouts and make them grow thickly and lushly.
I am aware that the above only outlines some issues connected with the blueberry cultivation. As a matter of fact such was my intention. More elaborate studies and detailed information can be found in specialist literature. Thank you for your interest in the blueberry cultivation and in our offer.