Fertilizers are manufactured from a wide variety of materials to supply plant nutrients. Once these materials are mixed, it becomes difficult to distinguish the materials present. In the past, a few unscrupulous manufacturers have taken advantage of this to increase their profit. To protect consumers and legitimate manufacturers from such practices, The Florida legislature enacted the first fertilizer law in 1889 and has amended it many times since enactment. These laws regulate the manufacture and sale of fertilizer in the state.
The law requires that the manufacturer purchase and affix a label to each bag, package, container, or lot of fertilizer offered for sale in the state. The law requires that each label show specific information about the analysis and composition of the mixture or material.
The key information comes in the guaranteed analysis section of the label. It tells you which of the primary plant nutrients: Nitrogen, Phosphorus and Potassium the fertilizer analysis numbers you’ve probably seen. For example an 8-8-8 fertilizer would be eight percent nitrogen compound, eight percent phosphorus compound and eight percent potassium compound.
There’s some other information in this section of the label that may seem even more complicated but it’s also important. The label tells you how much chlorine the fertilizer can contain. Chlorine can reduce the quality of some vegetable and flowers.
It tells you what materials the primary plant nutrients are derived from. This can help you determine the quality of the fertilizer.
Probably the most difficult part of the label to read certainly the hardest part to describe is the information listed right after the total nitrogen figure in the guaranteed analysis section. In addition the total amount of nitrogen, the label gives the amount of each of several types of nitrogen present in the fertilizer. This information will seem confusing, but it also tells you a lot about how the fertilizer will work in your soil.
You’ll see the terms nitrate nitrogen; ammoniacal nitrogen, water soluble organic nitrogen and/or urea nitrogen can be used by plants fairly quickly. You might look for these nitrogen forms in fertilizer for a vegetable garden. But nitrate and water soluble organic nitrogen are rapidly leached out of the soil so they don’t last very long. Ammonical and water insoluble nitrogen will stay longer in sandy soils.
Fertilizer with a high percentage of natural organic nitrogen is used by the plants slowly over a fairly long period of time. This kind of slow release fertilizer would be good for lawns helping them stay green without causing spurts of extra fast growth.
As I am sure you can tell by now, we can’t fully explain anything this complicated in one new article. But if you don’t remember anything else remember this; almost any fertilizer you buy in Florida is a good one if tit has the ingredients to do the job you want and if the price is fair in terms of the total amount of plant nutrients it contains.
For more information on Florida fertilizer label contact the Gulf County Extension Service @ 639-3200 or visit our website: http://gulf.ifas.ufl.edu or www.http://edis.ifas.ufl.edu and see Publication SL-3/SS170.