Mast producing trees, whether they’re soft mast like apple or persimmon, or hard mast like hickory nuts or oak acorns, should all be fertilized. It’s important to fertilize when you plant a tree, but it’s also important to fertilize mature trees if you want to achieve optimum mast production.
Obviously larger trees require more fertilizer than a newly planted seedling. With larger trees it isn’t necessary to cover the entire area from trunk to drip-line. Concentrating around the drip-line is the most important. The drip-line is basically where rain drips off the tree’s canopy and where the majority of smaller feeder roots will be located. A 5-10-15 fertilizer is perfect for most mast producing trees, but in absence a basic 10-10-10 can be used.
A very simple way to fertilize is with Tree-Paks. These biodegradable “tea-bag type” packets can be inserted into the soil around the drip-line of a mast producing tree and will help to produce larger, more nutritious yields from hard mast and fruit trees. If you have a thick canopy and no ground growth of grass or weeds, the fertilizer can simply be cast on the ground around the drip-line. If you have ground plant growth you’ll want to use a spade or sharp stick to open a hole about 4 to 6 inches deep to insert the fertilizer. You obviously don’t want the nutrients to go to the grass or weeds; you want it available for your trees.