Q: I have been trying to grow fruit trees from seeds. I noticed that all the bare-root trees I see at nurseries have a green pellet-type fertilizer or a green-colored emulsion for a starter fertilizer. What is it? How do I get it?
A: The pellets are no doubt a timed-release fertilizer. They're formulated to release fertilizer gradually over several months.
There are lots of brands and nutrient breakdowns, and commercial growers have access to sizes and types not available to home gardeners.
However, garden centers sell near equivalents in smaller packages. The best known brand is Osmocote, but you might also run into Dynamite, ClassiCote and others. Look on the label for the words "timed-released" or "controlled-release."
Most universities recommend a balanced nutrient breakdown for fruit trees, such as 10-10-10 (10 percent each of nitrogen, phosphorus and potassium). They also recommend about a half-pound of 10-10-10 for young trees, gradually increasing to a maximum of 5 or 6 pounds of that per year for mature trees. In most cases, you can even cut back on or cut out the phosphorus and potassium on mature trees, using just 5 or 6 pounds of 10-0-0 per year.
Osmocote's Flower and Vegetable Smart-Release fertilizer has a breakdown of 14-14-14. That would be a good choice, but since the nutrient content is a bit higher than 10-10-10, use less of it.
Balanced organic fertilizers (cow manure, worm castings, blends of blood meal, rock phosphate, etc.) also are good choices since they naturally break down slowly and act much like timed-released chemical fertilizers.
The ideal advice is to use only the exact fertilizer that your particular soil requires. So doing a soil test of your fruit-tree bed would be a good idea to tailor the product to your exact needs.
Besides cutting down on the number of fertilizings you have to do, timed-released fertilizers are much less likely to burn tender young tree roots.
Here's a link to a good article on fruit-tree fertilizing from Michigan State: