Deciduous trees should be fed  to promote optimal growth.   Depending on what the soil is like, you may need different types of fertilizers.  Fertilizers are commonly packaged with various combinations of nitrogen, phosphate, and potassium.  To determine exactly what is needed, a soil test needs to be done.  Kits are available for this purpose and are not cost prohibitive.  However, if you cannot do this, then the safe approach is to use a balanced fertilizer such as a 10 - 10 -10 or 13 - 13 - 13.

Since deciduous trees, like all plants absorb nutrients from their roots, it is important to make sure the fertilizer gets to them.  Besides the problems with turf and other plants, intercepting the nutrients, most trees have root systems at a relatively deep level.

Commercially available "root feeders" which deliver food in liquid form deep into the soil can be purchased at many gardening centers .  An alternative method can be used that achieves a similar effect.

Digging holes along the drip line will allow the fertilizer to reach the deeper roots more easily and will avoid surface plants from stealing the food intended for the tree. To do this, first cut a "U" in the sod (if present) and fold back the grass flap.   Use a crowbar or similar digging tool and dig holes three feet apart  and a foot deep (1 meter apart, 30 cm deep) along the drip line of the tree. Prepare a feed of a high nitrogen fertilizer mixed with equal parts peat moss (or sand). Using a funnel, dump in the fertilizer mix and top it off with peat moss and fold the flap of grass back.  This method is described in detail in Time Life "Trees" book.

You can put the fertilizer directly on the grass if the grass is wet. It will burn the grass if the grass is dry.  This method will cause the grass to grow thick and green, though, robbing the tree of some of its food.

The best time to feed your tree is early spring, when the soil is moist.  Fertilization forces out new growth, and new growth is more susceptible to cold damage than old growth. Therefore, it is usually recommended that fertilizer be tapered off in late summer, and not applied in fall, at least until after the tree is dormant. Once dormant, the fertilizer can be put down; the tree won't show signs of using it while dormant, but some will continue to absorbed and it'll be there as soon as the tree wants to grow in spring.

The amount of fertilizer used depends on the diameter of the trunk.   For trees with trunks under 6 inches, use 1 to 2 pounds of fertilizer for each inch of diameter.  For larger trees, use 2 to 4 pounds for each inch.

If you just buy tree spikes it will be easier, but a bit more expensive. Fertilizing deciduous trees WILL make them grow much faster/stronger.

Special thanks to Mike LaMana "Mike the Tree Doctor" for reviewing the contens of this article.
www.treedoctors.com