Fertilizing raspberries at the right time of the year helps the plants grow and produce tasty fruit. The best fertilizers start working as soon as your plants get transplanted into the ground. Additional applications help the plants reach their full potential.
Organic fertilizer or a 4-20-20 fertilizer works well when added to your planting site. You can also add well-rotted manure or compost to your raspberry planting area to help the new plants get a good start.
Specially formulated berry fertilizer works well on plants that are at least 1 year old. Well-rotted manure also helps fertilize the soil when added around the plant. The plants thrive with applications of nitrogen to help them reach their full growing height. But once the plants begin to set fruit, nitrogen applications should stop since the plant needs to focus on producing fruit rather than foliage.
The best time to apply a balanced 10-10-10 fertilizer is in early spring before the plant starts growing in March. Avoiding late spring or summer fertilization keeps the plants from producing succulent late season growth that's susceptible to damage in the winter.