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Blueberry cultivars are becoming more and more popular from year to year for growing both on industrial plantations and in small amateur garden plots. The most important role in the process of caring for this shrub is given to the application of fertilizers. Knowing how to feed garden blueberries in spring, summer and autumn, and how to do it correctly, you can create optimal conditions for its development and growth. Then the culture will undoubtedly “thank” for this with a healthy appearance and regular plentiful harvests.
Do blueberries need to be fertilized?
Garden blueberries are among those berry bushes, the need for additional feeding with nutrients is especially high. Most often, the natural composition of the soil on the site does not contain in sufficient quantities all the macro- and microelements required by blueberries – therefore, they must certainly be introduced artificially. At the same time, violation of the rules and proportions during the introduction of fertilizers turns into a slowdown in growth and weakening of the plant, a drop in yield, the appearance of pests and diseases.
What trace elements do blueberries need
For full development, abundant fruiting and providing fruits with vitamins, blueberries need soil rich in a set of certain chemicals and trace elements.
Nitrogen is vital for blueberries during the period of growth and formation of ovaries. Substances containing nitrogen are introduced into the soil immediately before planting the bush, and then the plant is fertilized with them 2-3 times during spring and early summer.
Starting from the period when buds begin to bloom, blueberries especially need top dressing containing potassium and phosphorus. Potassium affects the formation of plant protection against pests, resistance to lack of moisture. Phosphorus increases the vitality of the shrub, helps to increase the yield.
In summer, when the berries ripen, it is advisable to focus on potash fertilizers when fertilizing. You can also use complex compositions containing trace elements (primarily magnesium, which contributes to the process of photosynthesis in the leaves). This will help to achieve sweetness and good quality fruits. In addition, for the successful growth and development of blueberries, calcium, manganese, iron, copper, sulfur, zinc, boron, molybdenum, and sodium cannot be dispensed with.
In autumn, blueberries also need enough nutrients and micronutrients such as magnesium and zinc. At this time of the year, she will have to recover from fruiting and prepare for winter. In addition, at this stage, vegetative buds are laid for the next season, respectively, the autumn application of fertilizing to the soil will affect the yield next year. The presence of potassium in the soil to a sufficient extent is especially necessary for the plant to successfully endure winter frosts.
How does the lack or excess of nutrients affect the yield
In order for garden blueberries to develop successfully and consistently produce high, high-quality yields, it is crucial to maintain a balance of three elements: nitrogen, potassium and phosphorus.
An excess of nitrogen in the soil at the end of the season can lead to a deterioration in the quality of the berry, excessive growth of shoots that are likely to freeze in winter, inhibition of the growth of flower buds, which will negatively affect fruiting next year. The size of the fruit will decrease, their ripening will be delayed. At the same time, a lack of nitrogen will significantly slow down the growth of the bush, and the ripening of the berries will also occur slowly.
The content of potassium and phosphorus in the soil in excess of the norm can cause plant rot. The deficiency of these substances will manifest itself in a decrease in yield and deterioration in the quality of fruits, their critical shortage can lead to weakening and death of the bush.
In relatively large quantities, blueberries require magnesium, calcium and sulfur. Without these substances, the normal fruiting of this crop is also impossible, but they are introduced into the soil periodically, only as needed.
You should be especially careful with manganese, copper, boron, sodium. As a rule, there are enough of them in the soil to meet the needs of garden blueberries. Excessive concentration can be toxic to the plant.
When should blueberries be fertilized?
You can determine the lack or excess of a certain substance in the soil under blueberries by carefully examining the plant itself:
Cause | How it appears on blueberry leaves |
Lack of nitrogen | They turn yellow, starting from the edges, then acquire a reddish tint. Shrub growth slows down. Young shoots become pinkish. |
Excess of nitrogen | Get a rich dark green color. The bushes are very dense, tall. |
Phosphorus deficiency | They are compacted, are closely pressed to the stem. Over time, they acquire a purple hue, clearly visible in bright light. |
Lack of potassium | The upper parts of the plates die off, the edges warp |
Lack of calcium | The plates are deformed, a yellow rim appears along the edge. |
Magnesium deficiency | In older leaves, the edges are bright red, while the central part remains green. |
Boron shortage | The upper parts of the plates become bluish. Growth stops abruptly. |
Lack of iron | Young leaves turn yellow between the veins. |
Manganese deficiency | Yellowing between the veins, later the yellow parts dry and die off. |
Zinc deficiency | Stop growing. Get a lemon yellow color. |
Sulfur deficiency | Yellowish-white spots over the entire surface of the plate. Subsequently, they turn completely white. |
Mineral and complex fertilizers for garden blueberries
To provide garden blueberries with additional nutrition at different times of the season, mineral nitrogen or potassium-phosphorus fertilizers will be needed. To feed the plant in the spring (before flowering), complex formulations containing the three substances listed above are perfect. At the same time, it is not necessary to make the mixtures yourself – you can purchase ready-made “cocktails” for garden blueberries, including those whose composition is enriched with microelements and vitamins necessary for this culture, and may also contain growth stimulants and soil oxidizers.
Among the most famous and beloved by gardeners are ready-made complex dressings:
- Fertilizer “Good power” for blueberries and wild berries – a liquid composition that combines the three main macronutrients needed by these plants (nitrogen, phosphorus and potassium), 7 microelements, as well as vitamins B1 and PP. It also includes a growth stimulator – succinic acid. The consumption of the composition is small: 1 bottle is designed for 100 buckets of water. They are applied by watering, as well as spraying shrubs in the spring at the stages of budding, ovaries and berry formation. The use of “Good Force” improves the survival rate of a young bush, stimulates the growth of shoots, and significantly increases the yield.
- «Strong Bona“(fertilizer for blueberries and wild berries with bioavailable silicon) – granular top dressing with prolonged action. In addition to nitrogen, phosphorus and potassium, it contains silicon as a growth stimulator and activator of plant immunity, as well as magnesium and a number of microelements in a chelated form. It heals the root system, promotes the growth of shoots, the formation of ovaries, increasing the yield and sugar content of fruits. It is applied to the soil under blueberries 2-3 times a year – it is distributed over the surface of the soil and loosened.
- «Target High Yields» (Target Generous crops) is a complex fertilizer for blueberries in the form of granules. It contains nitrogen, phosphorus, potassium and 6 trace elements. Helps accelerate the growth of bushes, increase green mass, the formation of large and sweet berries. It is recommended to apply it in the form of a solution (5 g per 5 liters of water) under the root of the plant, 1 time in 2-3 weeks, from April to July.
- AVA – an innovative long-term complex top dressing, similar in mineral composition to volcanic lava. AVA capsules, granules or powder contain phosphorus and potassium, as well as 11 micronutrients, some of which are present in microdoses. This top dressing is optimally suited to meet the vital needs of plants of any type, helping them to develop more actively, endure winters more easily, and get sick less. It also has a positive effect on the size, taste and preservation of fruits. AVA fertilizer does not contain nitrogen, however, it helps to create conditions in the soil for the development of bacteria that extract it from the air. The dose recommended for feeding blueberries at any time of the year is 5 g per 1 bush (apply to the surface layer of the soil, then slightly loosen it). In summer, you can water the plants by dissolving 4 g of the composition in 1 liter of water, or spray the foliage with it at a lower concentration (2 g per 1 liter).
- Ogrod 2001 for blueberries – granular top dressing, specially adapted for plants growing on acidic soils. In addition to nitrogen, potassium and phosphorus, it contains 7 microelements necessary for these crops. After introducing this composition into the soil, the plants actively develop and bear fruit, their winter hardiness increases. Apply dry fertilizer 3 times during the season. The first feeding is carried out in April, each subsequent – with an interval of 30 days. Granules (35 g per 1 m2) are scattered on previously loosened soil in tree trunks, then watered abundantly.
Ways to fertilize garden blueberries
To feed blueberries correctly, you should not only choose the right fertilizer, but also apply it at the right time in the most optimal way for the plant, accurately calculating the dosage.
There are several ways to provide the plant with additional nutrition during the season:
- add dry fertilizer in the form of granules or powder directly to the soil;
- water the bushes with a nutrient solution dissolved in water;
- spray leaves and shoots with a solution of fertilizer.
In the first two cases, root feeding is carried out, since substances and trace elements are absorbed from the soil by the roots of the plant. This is the main way to fertilize blueberries.
General recommendations and rules for root dressing are as follows:
- it is desirable to carry out the procedure in the morning or in the evening – it is allowed during the day, but in cloudy weather;
- the soil under the plants must first be well moistened: if there has been no rain for some time, then a day or two before adding fertilizer, the blueberry bushes must be watered;
- within a radius of 15-20 cm from the near-trunk circle, lay a shallow groove, where top dressing should be applied – pour in a liquid solution or scatter dry granules over the soil surface;
- close up the fertilizer by loosening the soil;
- Pour plenty of blueberries with clean water.
Foliar feeding involves the supply of nutrients through the leaves. Their source is a liquid solution sprayed on the surface of the plates. This simple method is most often used in the summer, during the fruiting period of blueberries. It is most effective when it is necessary to make up for the deficiency of useful elements as quickly as possible – for example, if a large number of them were washed out of the soil as a result of prolonged rains, or the plant began to notice signs indicating a lack of something vital.
Features of making foliar dressings:
- the finer the composition is sprayed, the higher its concentration on the surface of the leaves will be;
- when determining the proportion of dilution of the drug for feeding, it is imperative to follow the instructions, observe the expiration dates;
- since blueberries have very dense leaves, often also covered with a wax coating, it is advisable to add a substance to the solution that promotes the adhesion of its particles to the surface of the plates (liquid soap).
Terms and rules for feeding blueberries from spring to autumn
You should be aware that annual blueberry bushes do not need to be fed additionally. Artificial introduction of nutrients begins from the second year of their life. Mature shrubs (6 years and older) need more fertilizer than young plants.
Feeding blueberries in spring, summer and autumn has its own characteristics and rules. They are clearly and systematically reflected in the material.
How to fertilize garden blueberries in spring
In the spring, blueberries need to be fertilized in order to stimulate their growth and development.
Top dressing during this period, as a rule, is divided into two stages:
- early spring (end of March and mid-April) – before sap flow begins and buds swell;
- flowering time of the plant (May-June).
How to feed blueberries for growth
At this stage, blueberries require mineral fertilizers with a high content of three key elements of its nutrition – nitrogen, phosphorus and potassium.
You can use complexes that combine all three of the listed substances (Nitroammophoska, Fertika-Universal).
Ammonium sulfate is considered the best simple mineral fertilizer to saturate the soil with nitrogen. For these purposes, ammonium nitrate and carbamide (urea) are also suitable. The rate of nitrogen fertilizers for a year for 1 adult blueberry bush is 50-70 g. Before the buds swell, half the dose recommended for the entire season is introduced into the soil. Top dressing is dissolved in water and applied under the root, avoiding contact with the leaves.
An adult blueberry bush also requires 30-50 g of phosphorus and 30-40 g of potassium per year. Superphosphate or double phosphate will help feed the plant first in the required amount. You can satisfy the need for the second with the help of potassium sulfate or potassium salt. In April, 1/3 of the annual norm of both substances is added to the soil under blueberries.
How to feed blueberries during flowering
During this period, blueberries spend a lot of energy on the formation of buds and ovaries. She needs the same minerals as in the previous stage, but in a different ratio.
The second portion of nitrogen fertilizers, 30%, should be fed to blueberries in the first decade of May. The last 20% must be applied to the soil in early June.
Also in early June, the plant should receive another 1/3 of phosphorus and potash fertilizers.
At the budding stage, you can also carry out foliar feeding with nutrients. For her, it is most convenient to prepare a solution based on a ready-made complex composition (“Good Power”), and then carry out abundant spraying of the bushes.
How to feed garden blueberries in summer
Top dressing blueberries in the summer, at the end of June or at the beginning of July, aims to ensure the filling of berries and abundant ripening of the crop. At this stage, the plant will need potassium and phosphorus – the remaining 1/3 of fertilizers containing these substances are added to the soil.
Also in June and July, you can feed blueberries with a nutrient mixture from a set of trace elements that it lacks. However, this should be done only when there is really such a need (this can be determined by the appearance of the plant or using leaf analysis).
How to feed blueberries in autumn
The last time in a season you need to feed blueberries in August and early September, after the harvest has been harvested. The goal is to strengthen the plant and increase its frost resistance.
If in previous periods all top dressings were applied in the required quantities, then at this time it will be enough to additionally feed the plant with magnesium sulfate (15 g) and zinc sulfate (2 g).
When fertilizing blueberries at the end of summer and especially in autumn, nitrogen fertilizers are not used. They stimulate the growth of the plant, increasing its green mass, which is completely unnecessary before the onset of cold weather. The shrub must have time to prepare for the winter, otherwise it is threatened with freezing.
What not to feed blueberries
It is strictly forbidden to use as a fertilizer for blueberries:
- organic top dressing;
- products containing chlorine or nitrates.
You should also not feed this culture with compositions based on folk recipes suitable for other berry plants (wood ash, eggshells, lime, dolomite flour, various herbal infusions). The listed fertilizers are not suitable for blueberries, as they cause a strong alkalization of the soil.
The same applies to the yeast-based nutrition mentioned in some sources. The benefits of it are very doubtful, since the yeast in large quantities absorb the oxygen necessary for the plant, and also compete with other beneficial soil flora.
Conclusion
In order to properly feed garden blueberries in spring, summer and autumn, you should know what substances the plant needs during these periods, when, how and in what quantity they should be added. Depending on the situation, additional nutrition should be added under the roots or through the leaves, having correctly prepared the mixture or calculating the proportion of the “cocktail” of minerals and trace elements. You should always remember that violation of the recommendations prescribed in the instructions for fertilizers, incorrect dosages or mistakes in choosing top dressings can significantly harm the plant. At the same time, compliance with all the rules of agricultural technology when fertilizing blueberries, along with measures for proper care of it, will certainly become the key to good yields and sweet, large berries.