Question
When is the best time of year to fertilize a maple tree and what should i use.

Answer
The best fertilizer for maples is 0-10-10 mixture. Maples do not need nitrogen.
How to Apply Fertilizer to your Maple Trees*:

1. Use 2 to 4 lbs. of fertilizer per inch of tree diameter. Two light applications (2 lbs./inch of tree diameter)梠ne in early spring and one late in the summer梐re better than one heavy application.

2. The roots of a sugar maple extend roughly the same distance from the trunk underground as the branches overhead. Spread the appropriate amount of fertilizer onto the ground through out the circle made by the tree抯 drip line