While wild wild blueberries bear fruit in summer even on very nutrient-poor moorland soils, cultivated blueberries need a little more energy to grow. They can only produce high yields with regular fertilization.
When and with what should you fertilize blueberries?
Blueberries should be fertilized twice a year: in April for optimal growth and at the end of May when fruit appears. Use low-lime fertilizers, e.g. special blueberry preparations or rhododendron fertilizer. Alternatively, acidic natural fertilizers such as composted needles, chopped softwood or bark mulch are suitable.
The right times to fertilize blueberries
When fertilizing cultivated blueberries in the garden, fertilization is carried out with two different purposes in mind, the growth of the bushes and the sufficient supply of energy for an abundance of fruit on the branches. The first fertilization of the year should therefore take place in April in order to enable the blueberries in the garden or in the pot to grow optimally. You should only give the plants the second dose of fertilizer towards the end of May at the earliest, when fruits are already appearing on the branches. After adding fertilizer, it is always important to rinse extensively with enough irrigation water so that the sensitive, ground-level roots of the blueberries are not damaged by too high a concentration of fertilizer.
Be careful with calcareous fertilizers
The selection of fertilizer for blueberries should definitely take the soil needs of the plants into account. The acidic environment of the soil at the location, with its pH value between 4.0 and 5.0, must not be influenced too much by the fertilizer administered. In addition to special preparations for blueberries, specialist retailers also offer low-lime fertilizers for rhododendrons and azaleas. However, if you use them just before or during the harvest season, you must clarify whether these flower fertilizers may contain ingredients that are harmful to consumption.
Natural materials for fertilizing blueberries
Manure and ordinary compost are generally not suitable for fertilizing cultivated blueberries because they contain too high a proportion of lime. If you don't want to fertilize your blueberries with artificial nitrogen fertilizers such as ammonium sulfate and ammonium nitrate, you can also use more acidic natural fertilizers. This particularly includes the following materials:
- composted pine and spruce needles
- chopped softwood
- Mulch from pieces of bark
- Cedar and Cypress Pruning
Since these natural materials only decompose relatively slowly, they can be applied to the soil around the blueberry plants almost all year round and carefully incorporated.
Tips & Tricks
When fertilizing with highly concentrated artificial fertilizers, it is always better to divide the fertilizer applications into small weekly portions, as this can prevent over-fertilization and damage to the plants.
