Plantation preparation depends on the chosen type of planting. What’s common to all of them is that the plot needs to be level, weeds and underbrush removed, and pitched enough to enable excess water to flow off.
If planting is done directly in the soil, it’s necessary to do soil and water analysis in order to consider different possibilities and advise.
Preparation
Blueberry thrives on naturally loose and well drained soils with pH values of 4.5 to 5.5. Altitude doesn't play a significant role if conditions are similar to the plants' natural habitats. This claim is supported by the fact that blueberry is cultivated in the Netherlands on plots 5 to 7 meters below sea level.
What are the conditions?
Soil is supposed to fit the category of strongly sandy loam, that is, with a higher percentage of sand, lower percentage of clay, rich in humus and pH around 4.8. Small aberrations can be regulated by fixing physical-chemical properties, though if the plot doesn't satisfy them, blueberries can be grown in pots and sacks or on banks with substrate. If none of the previous works, a new, more suitable plot is acquired.
What's important is to have a strong desire and determination to engage in this interesting and profitable business.
What are the conditions?
Soil is supposed to fit the category of strongly sandy loam, that is, with a higher percentage of sand, lower percentage of clay, rich in humus and pH around 4.8. Small aberrations can be regulated by fixing physical-chemical properties, though if the plot doesn't satisfy them, blueberries can be grown in pots and sacks or on banks with substrate. If none of the previous works, a new, more suitable plot is acquired.
What's important is to have a strong desire and determination to engage in this interesting and profitable business.
Growing blueberries in 50-liter sacks, in which the plants can live up to 10 years, has become accepted in Serbia. Alternatively, according to Dutch methods, channels are dug and filled with acidic peat/substrate (minimum 20 to 40 mm granulation), up to 200 liters per running meter, to form beds over which banks are formed by machines.
In the case of low soil pH values, low nitrate and copper content, and high amounts of organic matter, mycorrhizal fungi is introduced to the soil to create a symbiotic relationship with blueberry roots. Symbiosis induces root enlargement, boosts nourishment, and strengthens the plant, therby increasing the yield and juiciness of the fruit. Blueberry inoculation and later supplementation with mycorrhizal fungi raises the amount of nutrients in the soil and fertilization efficiency, improves water usage, and protects the plant from toxic elements.
Delivery
Blueberry seedlings planned for growing on large areas are delivered in 2, 3, and 5 liter pots. Seedlings are laid down in pallet boxes with a capacity of 90 to 220 pots – depending on the pot size and plant habit. Wooden pallet boxes are necessary for plant transportation and are charged for.
A standard tow-truck can hold 52 pallet boxes with maximum 11000 plants – the future blueberry owner needs to plan on the use of such a vehicle, as well as a place of delivery with a hard surface and forklift for unloading.
Transportation of seedlings with leaves, or even with fruits, is delicate and can result in damage to the seedlings caused by friction in an enclosed space, or even sickness of the plants due to the high moisture level and poor drafting. For those reasons we don't recommend setting up professional plantations until autumn, unless the distance from our nursery is short.
Smaller amounts of seedlings can be transported without pallet boxes, by arranging them on the vehicle floor or in cardboard boxes. In that case the future grower should provide manpower for unloading the pots with seedlings. Advice to all parties included in the delivery chain is to handle the package with care to avoid breaking the branches.
Direct takeover from Superior's nursery is also an option.
Smaller amounts of seedlings can be transported without pallet boxes, by arranging them on the vehicle floor or in cardboard boxes. In that case the future grower should provide manpower for unloading the pots with seedlings. Advice to all parties included in the delivery chain is to handle the package with care to avoid breaking the branches.
Direct takeover from Superior's nursery is also an option.
Personal garden growers can obtain their seedlings in agriculture pharmacies or directly from Superior. These seedlings have been removed from their pots, and the roots wrapped in plastic to retain moisture for as long as possible.
Planting
Blueberry can be planted any time, even in the middle of the summer. What’s important in this case is that planting areas should be prepared and watered and irrigation systems tested. Seedlings need to be unpacked promptly, removed from their pots (pots are not biodegradable), planted as deep as they were in the pots, then covered with soil and well compacted.
Seedlings can be planted any time during the autumn, winter and early spring if the soil isn’t frozen or drenched with rain water – planting in frozen ground is not possible, while in mud is possible but the plot and future plantation functionality is compromised.
It's believed that there's enough atmospheric moisture in autumn/winter and early spring. However, in the last few years, due to climate change, rainfall has grown scarce, so it's recommended to set up and test an irrigation system before planting.
Small holes are filled with 5 to 30 liters of substrate mixed with around 50 grams of Agroblen fertilizer (amount depends on soil quality), then partially excavated by hand to make space for placing the blueberry seedling roots. For easier rooting and better plant growth, before placing the root in the hole, its lower part should be shaken with one hand to remove excess substrate. The seedling is then held vertically at the appropriate height with one hand, while the other hand covers the root in the hole with soil and substrate, then compresses them for improved contact between the root and the soil.
Blueberry is a self-pollinating plant that doesn't need a pollinator, that is, another variety from which the insects would transfer pollen. However, scientific research from a California university confirms the importance of having various varieties on the plantation for at least two reasons:
First of all, early varieties attract insects such as bees and bumblebees during the full blossom of the primary variety - insects will "know" where the good and strong pasture is and they will visit blueberry plants in large numbers.
Secondly, plants defend themselves from self-pollination by slower germination of their own pollen through the stigma than other varieties. With more than one variety in the orchard. pollination is faster, and that prevents flower fall-off caused by late frost. The better the pollination and more insects visiting the plants, the more pollinated flowers in the corymb, thus more fruits. The more pollen grains sprout through stigma and form seed germ in the pistil, the more seeds in the fruit, hence the fruit will be larger. Finally, the larger the fruits and their quantities, the higher the blueberry yield.
Maintenance
Serious work with blueberry plants starts after the plantation is set up. Planting is just the “beginning of a school year”; lots of exams are ahead.
Blueberry orchard maintenance can be divided into a few categories:
- Irrigation
- Fertilization
- Disease and pathogen protection
- Weed protection
Irrigation - It's mandatory; without enough water and good quality water, successful production is not possible. It's necessary to assess water abundance and quality at the start, because after planting there won't be enough time for corrections.
Fertilization - For high yields and satisfying fruit quality it's necessary to fertilize blueberries during the whole season. Various fertilizers adapted to blueberry growing are available.
Disease and pathogen protection - Plant protection is still poorly observed in Serbia because blueberry cultivation has only relatively recently become more widespread. Our experiences tell us that blueberry plants have to be protected from insects and diseases in phases, as both prevention and cure.
Weed protection - This is the part of maintenance that producers are most bothered with. Some weed seeds and certain rhizomes can hibernate for many years and activate when conditions allow, regardless of any previous spraying with herbicides. Wind can also move weed seeds from ruderal habitats to the plot, substrate, banks, near the pots, etc. Timely activities such as weeding and mowing, even chemical treatments will save time and money, since the weeds that overgrow the area around the seedlings require a lot more manpower and removal agents. Between the plants in the rows and on the edges of the banks, weeds can be removed manually, mowed with string trimmers, or treated with permitted concoctions such as Basta. Space between the rows can be mowed, milled, or subsoiled - whatever works for the grower. In the end, mowing can be a pleasant break from daily duties and an opportunity to examine the plants and conditions in the orchard.
Pruning
Pruning is the most important aspect of blueberry cultivation. For long-term yield stability it’s recommended that the bushes be pruned once a year – occasional pruning creates an uneven balance between old and young branches. Through pruning the plant is shaped and the yield and fruit size is planned.
Bushes with the highest yield contain around 15-20% young branches (<2.5 cm diameter), 15-20% old branches (3.5 cm diameter) and 50-70% medium-aged branches. The most productive branches are between 2.5 and 3.5 cm at their base and 4-6 year old, though some young branches are needed for rejuvenation and some older ones for support.
During each quiet season, the largest branches are supposed to be removed to their base so that the light reaches the middle of the bush. While deciding which branches to remove, it's important to consider the overall state of the bush. Weak or diseased branches are to be removed first, as well as the ones that spread poorly or are damaged by extreme cold. Avoid leaving small stumps by cutting as close as possible to the main branch.
Summer pruning is done right after harvesting. All newly sprouted little branches are trimmed, and new summer-grown branches with one tip are trimmed to form many heads and strengthen the lower part of the stem that will carry the fruits. After this pruning, plants should be treated with fungicide.
Winter pruning is conducted in the late winter or early spring by eliminating small, irregular branches and shortening the tall branches to form a goblet shape.
We're happy to have visitors over to Superior during the pruning season to provide demonstrations of proper blueberry pruning technique. Get in touch to schedule a visit.
Harvesting
Every fruit grower’s favorite time is the harvesting period. At altitudes around 100 meters, blueberry variety Duke ripens in Serbia in the second decade of June and it can be harvested until the mid July. The highest price is reached in the beginning of June, so get ready for that niche that is still open to Serbian growers.
Blueberry is harvested in many flushes, the first of which brings around 20% of overall yield, the second around 60% and the third again around 20%. If the weather conditions allow, that is, if it’s warm during the ripening season, Duke can be harvested even at the start of June. Sometimes all the fruits ripen at once and it’s possible to carry out one huge harvest, after which the whole plantation is inspected one more time to pick up the remaining later-ripened fruits.
Only fruits at least 12 mm wide are harvested, and those with a diameter of 22-26 mm are of the best quality. Manual harvesting involves both hands picking only the large, ripe, undamaged fruits for sale as first class, and smaller and slightly damaged ones for industrial use, juices and jams.
The best time for harvesting is in the early morning and in the evening so that both the pickers and the fruits are protected from excess heat. Fruits are not supposed to be moved around too much between the fingers and in the hands so that the bloom, which gives the characteristic color to blueberries is not removed. They have to be handled with care, since dropping from a height can damage the fruit and lower its price. Berries are placed in crates that hold 3 to 6 kilograms, and are stored in cold areas until the time of a takeover. For longer storing, the storage areas shouldn't be warmer than +4°C.
Blueberry can be harvested by machines too. On the Serbian market, domestic (Kokan) and foreign (Oxbo) machines pick mostly ripe fruits, though some green one gets picked too. These products go to a selector afterwards so that the final buyer gets the requested blueberry quality.
It's important to know that the problem of finding the manpower - the pickers - rises from year to year. In the first years after the planting, when the bushes are still small and the fruits are sparse, the efficiency of one picker is around 20 kilograms a day. Older blueberry bushes yield from 2 to 3 kilograms of fruit and efficiency is doubled, so it's possible to pick around 50 kilograms a day per picker, but that requires preparation and training.
Storage
Within 4 hours of harvesting, blueberries need to be chilled. Chilled fruits keep their hardness and their shelf life is exceeds by up to 10 times that of non-chilled berries that soften up and rot due to their metabolism speeding up due to high temperature. Crates packed with fruit should be stacked in a way that will allow the air, desirably conditioned, to flow and cool the berries.
After the berries are cooled down, it’s recommended for them to be kept at 0-1°C and 85-95% relative air moisture. Under such conditions blueberries can keep for 2-3 weeks. The critical temperature for blueberry freezing is -1.3°C.
Effects of storage temperature (mass and fruit hardness) differ between blueberry varieties.