Fertilizer Foibles

One of the things that we all do but many may know little about is fertilizing. Whether we apply or specify it, many do not know enough about what we’re doing. Yes, we understand the local laws and ordinances which govern fertilizer applications. Yes, we have heard or are tangentially aware that runoff can kill our ecosystem and environment. Yes, we have reviewed the Best Management Practices for fertilizing, and we are at least (hopefully) aware of the fact that ANSI A-300, Part 2 has a complete standard written about fertilization. But so many of us don't really get it.

Recently, I have seen an increase in lawsuits regarding fertilizer; both regarding specificity and application. Very expensive palm trees were recently killed due to the incorrect specificity regarding what to apply and at what rate to apply it. If you are specifying fertilizers and fertilization, you are at ground zero for a lawsuit in negligence as it relates to what you do not know about fertilizers.

Take for example a landscape architect who recommended an 18-0-18 be applied to 35 Medjool palm trees. They all died due to fertilizer burn. In addition to not specifying a rate of application (how many pounds of fertilizer per tree should be applied), there was no mention of the nutrient derivation in the nitrogen source. Of course, the applicator selected a fertilizer containing all urea nitrogen which is "hot" enough to light a campfire in January. When you author a set of specifications, (fertilizing, pruning, spraying, etc.), you are providing a legal framework from which a written contract is agreed upon by different parties. If something goes wrong, as the author of the specifications, you will find yourself pressed to defend them.

Here is a short quiz that may help. Nobody will know if you passed or not -- except you. The quiz contains entry level questions (e.g. the shallow end of the swimming pool type of questions) and only takes a few moments to finish. 

NOTE: Assume a bag of 10-3-15 is being used as an example for the following questions.

1.     Define a fertilizer analysis? What is the analysis in the example bag of fertilizer?

2 .     Define a fertilizer ratio? What is the ratio in the example bag of fertilizer?

3.      What does the first number (10) on the example bag of fertilizer refer to? The second number (3)? The third number (15)?

4 .    What element must fertilizer contain to be termed organic?

5.      How many pounds of potassium are in this 50-pound bag of example fertilizer?

6.      You have a tree that measures 65 feet in canopy radius. What is the size of the area to be fertilized in square feet?

7.     How many actual pounds of fertilizer must be applied per 1,000 sq. ft. to apply 2 pounds of nitrogen?

8.      What nutrient is the #1 deficiency of palm trees?

9.      By weight, what nutrient is most required by trees?

10.   What are nitrogen, phosphorus, potassium, and sometimes magnesium collectively referred to as?

11.    What are the remaining nutrients collectively referred to as?

12.    What nutrient becomes more available as soil pH increases?

13.    On the soil pH scale, what value is termed neutral?

If you apply fertilizers as part of your job description and you could not answer two or more questions, you may want to consider brushing up on the subject. If you make recommendations or specificity for others to bid on and missed any of the questions, you may want to reconsider making fertilizer recommendations until you have a better mastery of the subject.

To get answers to the above questions, email: joesamnik@experttreeconsultants.com or visit: www.experttreeconsultants.com.