Avoid fertilizing after August 1 st. Two Types of Raspberry Plants – Summer Bearing and Fall Bearing. ... Milo Berries ‘White Frost’, Bundle of 3 $ 8.99 Add to cart. Step One: Know When to Fertilize There IS a right and wrong time to fertilize your trees. Fruit trees need good nutrition to grow and produce an abundant harvest, just like vegetables, flowers, and other plants. Remove dead or damaged canes in early spring. Repellant-Repellex $ 39.99 Add to cart. Or keep reading here to learn the 5 Easy Steps for fertilizing your fruit trees! After applying the fertilizer … The best time to fertilize raspberries is in the spring before May with 10 10 10 fertilizer. Learn when to fertilize and how to fertilize your garden and lawn in Minnesota. Fertilize raspberries early in spring for maximum growth. Late summer and early fall are the best times of year to fertilize your garden and lawn. When to Fertilize. Annual fertilizing after first year: Add actual nitrogen or a 10-10-10 nitrogen fertilizer, a higher amount added in the second year. For two year old or older trees we recommend waiting at least two months after planting then fertilize with a time-released fertilizer such as Scotts Osmocote Plus Outdoor & indoor (15-9-12) or Espoma Holly Tone, or Tree Tone Organic Fertilizer. Pick ripe raspberries every few days to avoid spoilage. Raspberries also do well with well-rotted manure. In our helpful video, Tricia explains if, when, and how much to fertilize your fruit trees. First year fertilizing plan: After planting and the soil has settled, add actual nitrogen or a 10-10-10 nitrogen Remember to keep about 3"-4" away from the base of the plant to avoid burning the roots.