1, variety selection
There are many varieties of blueberries. At present, there are three main categories: high-bush blueberry, rabbit-eye blueberry and short-bush blueberry. Among them, high-bush blueberries are divided into south bush, north bush and half bush blueberries. Suitable for potted plants in northern areas are mainly northern high-bush, semi-high-bush and short-bush blueberries, and the recommended varieties are: Lanfeng, Jin Lan, Duke, Bijita, Hokuriku, Beicun, Beilan, Maiden and Svik. Some varieties of blueberry have low self-pollination rate, so it is best to cultivate many varieties together when potted, which can improve fruit quality and yield.
2. Potting technology
2. 1 basin selection
Blueberries like loose and breathable soil, and it is best to use breathable pottery pots and pots for family potted plants. Generally, 3-year-old blueberry seedlings choose pots with an inner diameter of 25 ~ 30cm, and 4 ~ 6-year-old blueberry seedlings choose pots with an inner diameter of 30 ~ 40cm to meet the cultivation requirements. If conditions permit, you can also choose wooden cases made of anticorrosive wood. Plastic pots and porcelain pots are not recommended because they are airtight.
2.2 Soil regulation
Blueberries like acidic soil, and the optimum pH value for the growth of high-bush blueberries in the north is 4.5 ~ 4.8, and that for short-bush blueberries is 4.0 ~ 5.2. If the soil pH value is too high, it is generally reduced to a reasonable range by applying sulfur powder. The adjustment of soil pH value should be carried out 5 ~ 6 months before planting, and should be combined with increasing soil organic matter and applying base fertilizer. Generally, when the soil with a pH value of 6.5 ~ 7.5 is adjusted to a pH value of 4.5, 1kg of lump-free sulfur powder is required for every 1m3 of soil.
Blueberries like soil rich in organic matter, and the organic matter content should be 8% ~ 12% in family cultivation. Family potted plants can be made of garden soil, acidic humus soil and peat soil, which are common in flower markets. The ratio of garden soil: peat soil: humus soil is about 2: 1: 1. The prepared soil should be loose, breathable, well drained and rich in organic matter.
Pine needles, rotten pine bark, crushed crop stalks and rotten sawdust are all good materials for potted blueberry pots.
2.3 Planting method
Usually, potted plants are selected before the spring buds germinate. When planting in summer and autumn, it is necessary to do a good job in water management after planting and trim properly to improve the survival rate of seedlings.
When planting, if the seedlings have clods, they can be planted directly. First, loosen the roots by hand, so that the roots can quickly adapt to the new environment after planting and promote the growth of new roots. Fill the pot with 1/3 soil, compact it slightly by hand, then cover it with a new layer of soil, put in seedlings and stretch the roots as far as possible, and cover the soil to 3 ~ 5 cm below the pot edge. Gently lift the seedlings and stretch the roots, and finally compact the basin soil to avoid ventilation, and irrigate it in time after planting. Bare-rooted seedlings are not recommended, because bare-rooted seedlings are easy to carry germs and are not easy to survive.
3. Daily management
3. 1 water management
Blueberries are water-loving plants and belong to fibrous roots. Its absorbing roots are as thin as hair and shallow in distribution, generally distributed in the soil layer 5 ~ 20 cm below the surface, so it has poor drought resistance and likes humidity, so it needs well-drained soil, and watering is extremely important during the growth period. Generally, it is recommended to use pollution-free pond water, river water, reservoir water and natural precipitation for irrigation, which is difficult to achieve family maintenance. Well water and tap water should be kept in open containers for several days before being used for irrigation.
When watering, it must be watered thoroughly, but there should be no water at the bottom of the basin. When blueberry is short of water, the leaves on the new shoots will droop slightly, and the growing fruit will shrink and become dull, so water it as soon as possible. However, daily watering should generally be carried out after sunset in the morning or evening, and try to avoid watering under the scorching sun. Good and sufficient water supply is the key to the success of blueberry planting.
Water should be reduced before fruit ripens to prevent excessive nutrient growth and fruit cracking. Before falling leaves in autumn, water should be reduced to enrich branches and prevent them from pulling in winter.
3.2 Fertilization
Blueberry is an oligotrophic plant. Compared with other fruit trees, it needs less nitrogen, phosphorus and potassium, so excessive fertilization should be prevented. Because it is carefully determined according to the situation of the tree. Blueberries are sensitive to chlorine fertilizer, so it is not suitable to apply chlorine-containing fertilizers such as ammonium chloride and potassium chloride. Generally, mixed fertilizer or potassium sulfate with the ratio of 1: 1: 1 is applied, in which potassium sulfate can also reduce the soil pH value.
Potted plants have already mixed enough organic matter into the soil at the initial stage of planting, and no fertilization is needed. Generally, topdressing is only 1 time at berry maturity. After potted for 3 years, the soil fertility decreased with the increase of trees, and the soil was changed when changing pots.
3.3 lighting
Blueberry is a long-day plant, and it needs a long light time and intensity in its growing period. If you grow in shaded or semi-shaded environment for a long time, the yield will be greatly reduced. Therefore, it is more suitable to plant blueberries in Nanyang Terrace, but the sunlight reflected by the concrete surface and tile wall of the balcony is too strong to burn blueberry leaves.
3.4 Effect of temperature on blueberry
Blueberries with high, semi-high and low clumps in the north shed leaves in winter in the north, which requires a certain cooling capacity to complete flower bud differentiation. If the cooling capacity is not enough, blueberries will only blossom but not bear fruit. Hebei area can survive the winter by keeping the basin soil moist on a closed balcony, and it will blossom and bear fruit normally in the coming year.
4, plastic pruning
Pruning of potted blueberries can be divided into dormancy pruning and growth pruning.
Winter pruning of young trees is mainly to cut off weak branches and drooping branches at the lower part. After spring germination, flower buds, twigs and branches of diseases and insect pests should be properly removed to reduce the fruit, so as to strengthen the tree potential, expand the crown, increase the number of branches and promote root development.
After planting for 3 years, the crown of blueberry in the fruiting stage basically took shape. At this time, pruning is mainly to control tree height, improve ventilation and light transmission conditions and increase fruit yield. When pruning, cut off long and short fruit branches, keep medium fruit branches, thin fruit branches, overlapping branches and over-dense branches. To control the vigorous growth of branches and the further expansion of the crown, in principle, go weak and stay strong, leaving limited space and nutrients to the fruiting branches.
5, pests and diseases
Common diseases of blueberry include downy mildew, fruit rot, canker, scorch, leaf spot and mosaic. Generally, carbendazim, thiophanate-methyl and mancozeb are sprayed regularly. In daily cultivation, attention should be paid to controlling plant spacing, ensuring sufficient light and good ventilation conditions, which can reduce the occurrence of some diseases. Aphids and tetranychus urticae can be sprayed with imidacloprid, and fruit eaters can catch them manually. Do not use medicine before fruit picking 1 month.
Step 6 harvest
Potted plants should be combined with early and late maturing varieties to prolong flowering and harvest periods and improve ornamental value. Usually the fruit can be harvested after it turns purple 1 week.