What conditions are needed for growing blueberries?
The blueberry is also known as lanmei, dusi, dushi, and so on. It is a perennial shrub of the genus Vaccinium in the family Ericaceae, named for its blue fruit. It is rich in nutrients, containing not only conventional nutritional components but also extremely abundant flavonoids and polysaccharide compounds, and it has very high cultivation value and market prospects. Let us take a look below at what conditions are required for blueberry cultivation!
Growing conditions for blueberries
1. Climate: Based on China's climate characteristics and the growth habits of different blueberry cultivar groups, the growing regions can be broadly divided into four production areas: the Changbai Mountains and the Greater and Lesser Khingan Mountains blueberry production area, the Liaodong Peninsula and Jiaodong Peninsula blueberry production area, the Yangtze River Basin blueberry production area, and the South China blueberry production area.
2. Soil: Blueberries are suited to sandy loam soil that is loose and well drained, with a soil pH of 4.0-5.5, the most suitable soil pH being 4.3-4.8, soil organic matter content of 8-12%, and the optimal soil water table at 40-60 cm, with the soil moist but not waterlogged.
3. Water: The blueberry root system is relatively shallow and quite sensitive to lack of water. In most cases, timely irrigation is needed according to soil moisture conditions. River water, reservoir water, or groundwater can all be used as irrigation water sources, but water sources with high salinity and high pH should be avoided for irrigation.
4. Terrain: For blueberries, relatively gentle flat land or gently sloping land should be chosen. Although mountainous land with steeper slopes helps improve fruit quality, it brings a lot of inconvenience to field operations. Valley land or low-lying plots should be avoided for blueberry cultivation so as to prevent frost damage during the flowering period.
Cultivated varieties of blueberries
1. Highbush blueberry: Highbush blueberries have relatively large fruit, good quality, and a good fresh-eating taste. They can be cultivated as a variety for sale on the fresh fruit market, and can also be cultivated for processing or for home use. They include two main categories: southern highbush blueberry and northern highbush blueberry.
① Southern highbush: Southern highbush blueberries prefer moist, warm climatic conditions and are suitable for development in areas south of the Yellow River in China, such as central and southern China. Excellent varieties include Sharpblue, O'Neal, Misty, and so on.
② Northern highbush: Northern highbush blueberries prefer cool climates and have strong cold resistance. Some varieties can withstand low temperatures of -30°C and are suitable for development in the humid coastal areas of northern China and cold regions. Excellent varieties include Coville, Darrow, Bluecrop, and so on.
2. Half-high blueberry: Half-high blueberry plants are relatively shorter, with large fruit, excellent quality, and strong cold resistance, usually able to withstand low temperatures of -35°C. They are suitable for cultivation in the cold regions of the north. Excellent varieties include Northland, Northblue, Northcountry, and so on.
3. Lowbush blueberry: Lowbush blueberry plants are short and have extremely strong cold resistance, able to be cultivated in low-temperature regions of -40°C. Cultivation and management are also relatively simple, making them suitable for large-scale commercial cultivation in the high-cold mountainous areas of Northeast China. Excellent varieties include Blomidon, Fundy, and so on.
4. Rabbiteye blueberry: Rabbiteye blueberry plants are tall, long-lived, resistant to heat and humidity, not demanding regarding soil, and drought resistant, but they have poor cold resistance. They are suitable for cultivation in the hilly areas south of the Yangtze River Basin in China, South China, and other regions. Excellent varieties include Baldwin, Gardenblue, Powderblue, and so on.
Planting methods for blueberries
1. Deep plowing and land preparation: After the blueberry site is selected, deep plowing should be carried out 1 year before planting together with green manure incorporation, with a depth of 20-25 cm being appropriate, to deepen and mature the soil. For soil types that do not meet blueberry requirements, soil improvement should be carried out before planting to favor organic blueberry growth.
2. Planting time: In the south, where winters are not very dry, planting from autumn to before early spring budbreak is best. In places with dry autumn and winter, planting when the rainy season arrives is appropriate. In places with irrigation conditions, planting can be done in all four seasons, and in Majiang, Guizhou, planting can also be done in summer.
3. Planting density: The planting depth for 1-year-old seedlings is 15-20 cm, and the soil must be firmed by hand and tamped down, following the practice of “three lifts, two tamps, and one lifting of the seedling.” Rabbiteye blueberry often uses 2×2 m or 1.5×3 m, highbush blueberry 1.2×2 m, and lowbush blueberry (0.5-1)×1 m.
3. Pollinator trees: Rabbiteye blueberry must be provided with pollinator trees. Highbush blueberry and lowbush blueberry have relatively high self-fruitfulness, but providing pollinator trees can also improve fruit quality and yield. The arrangement method uses a 1:1 or 1:2 ratio of the main cultivar to the pollinator cultivar.
4. Soil management: The blueberry root system is relatively shallow and fine, without root hairs, so the soil is required to be loose and well aerated.
① Clean cultivation: Clean cultivation can be carried out from early spring to August. After autumn begins, clean cultivation is unfavorable for overwintering. Highbush blueberry cultivated on sandy loam commonly uses clean cultivation, with a depth of 5-10 cm being appropriate; too deep can easily damage the root system.
② Sod culture: That is, growing grass between the rows. Compared with clean cultivation, sod culture is likewise beneficial for increasing yield and has the advantages of maintaining soil moisture and facilitating mechanical operations.
③ Mulching: Soil mulching is widely applied in blueberry production and has multiple effects such as increasing soil organic matter, improving soil structure, regulating and maintaining soil moisture, lowering soil pH, and controlling weeds.
5. Fertilization method: When fertilizing blueberries, it is recommended to use organic fertilizer. China's farmland has already suffered serious pollution due to excessive use of chemical fertilizers, ultimately leading to reduced yields or even total crop failure.
① Fertilizer types: Applying nitrogen-phosphorus-potassium compound fertilizer gives better results than applying a single fertilizer. The ratio of nitrogen, phosphorus, and potassium fertilizers should preferably be 1:1:1. Ammonium-form nitrogen fertilizers such as ammonium sulfate are preferable; nitrate nitrogen fertilizers should not be applied, and chlorine-containing fertilizers such as ammonium chloride and potassium chloride should not be chosen.
② Fertilization method: Highbush and rabbiteye blueberries can use the furrow application method, with a depth of 10-15 cm being appropriate. Fertilization is carried out before budbreak in early spring, and 1 more application can also be made during the berry ripening stage.
③ Fertilization amount: Excessive fertilization can very easily injure blueberry plants or even kill the entire plant, so determining the fertilization amount must be done very carefully and must be based on soil fertility and the nutritional status of the plant.
6. Irrigation method: The blueberry root system is shallow and prefers moisture, so timely irrigation is very necessary, but attention must be paid to the water source and water quality. Deep well water generally has a relatively high pH and high sodium and calcium content, so sulfuric acid can be used to adjust the pH to about 4.5-5.5 before irrigation.
7. Disease control: Diseases affecting blueberries include fungal diseases, bacterial diseases, and nematodes, but since China is a newly introduced cultivation area, the occurrence of pests and diseases is relatively low, and routine preventive work is sufficient.
8. Timely harvesting: The fruit ripening period of rabbiteye and southern highbush blueberries is not uniform. Generally, harvesting needs to continue for 20-30 days, usually once a week. For fresh fruit consumption, the fruit should be picked by hand; for processing, mechanical harvesting can be used.