Provo City

Fertilizing

Tree Care
Fertilizer is not plant food. Plants make their own food through a remarkable process called photosynthesis. So what is fertilizer? Fertilizer is a mixture of essential elements, usually nitrogen, phosphorus, and potassium, needed for plant growth. Ideally, adequate amounts of these elements would all be found in the soil. This is not always the case. Sometimes incorrect management practices or simply the climate of an area can lead to a deficiency of the essential elements. When this happens, they must be reapplied. The simplest way to do this is to fertilizer.  
 
When to fertilize
A tree that is growing at the appropriate rate and not showing signs of deficiency or stress probably does not need fertilization. Trees growing in turf that is routinely fertilized, particularly when clippings are returned to the soil, may not need supplemental fertilizer. When a tree needs fertilizer not all of the essential elements are needed. It maybe that only one element is needed. This is important because if fertilizer is not needed or not applied wisely, the tree will not benefit. In many instances the tree could actually be harmed by the unneeded application.

 


Knowing What to Apply 
Nitrogen is the most often limiting nutrient. Nitrogen deficiencies are most common in sandy soils low in organic matter, especially where irrigation is heavy. Nitrogen deficiencies are characterized by reduced growth. Smaller leaves are also typical. Yellowing of leaves, especially older leaves, is also indicative. Newer leave on a nitrogen deficient tree often appear much greener.

Iron deficiencies although not as common as nitrogen deficiencies are often a problem in our Utah climate. Iron deficiencies are characterized by young, small, yellow leaves. Often the leaves are yellow with green veins. Older leaves are darker green. Iron deficiencies should be treated as they can eventually kill a tree. 

Newly planted trees should not be fertilized until the following year. This allows the tree to establish a healthy root system. If you suspect that there is a serious problem with your tree, it is best to have a certified arborist diagnose it.