Thoughts on Organic Fertilizers

We hear a great deal about "organic fertilizers" in just about every type of media outlet. There are lots of articles, magazines, books, videos, and societies about organic fertilizing. The idea of organic fertilizer is somewhat more of an integrated garden  lifestyle than a science, although there is plenty of science involved, just not the sort we're used to seeing on most fertilizer containers. Let me cast a bit of light on the ideas of organic versus synthetic fertilizers.

a serious punch of

On most synthetic fertilizers, we'll see the ingredients listed as we would see on a food container: the primary ingredients are listed in order of their occurrence.There are guaranteed percentages of ingredients like urea, ammonium phosphate, potassium nitrate, and so on. There are secondary ingredients such as iron and manganese compounds, copper, boron, and so forth. The components are listed in precise percentages, and with many commercial products, you get a guaranteed and predictable product, batch after batch. 

There is a growing resistance to using synthetic fertilizers on food crops, and many rose growers will prefer to use organic fertilizers rather than synthetic ones. Why would plants prefer one type of fertilizer over another ? Why would people prefer to use one product over another ? 

Organic fertilizers are made from natural materials, in most cases. The myths are that organic fertilizers are "better" for the plants, safer for the Earth, and won't burn plants or pollute the environment. In many cases this is true, but there are some serious misunderstandings in the widespread use of organic fertilizers. In the first place, we need to better understand what the needs of plants are to be able to fertilize them well. A good example is the use of manure as an organic fertilizer.

one of the few sources
of organic potassium

It is very common for people to use manure as a garden soil, not understanding that many plants won't react well to the high urea-nitrogen content.  Manure also lacks phosphorous or potassium. Adding lime or bone meal to manure solves one of the missing ingredients, but potassium is still lacking. Adding greensand or muriate of potash makes a more complete fertilizer, but you have an expensive, albeit organic, fertilizer. Any single component of organic fertilizer affects a stage of growth, and the real key to successful organic fertilizing is to use a complete fertilizer, satisfying the plants' needs for nitrogen (N), phosphorous (P), and potassium(K). Many bulb plants need more P than N, yet richly organic soils will promote foliage growth more so than solid roots and bulb formation. 
Roses need a greater amount of  P and K to produce good blooms, whereas Canna lilies need more N than P to produce the green stems that produce the flower heads. 

a good choice for an all-purpose
organic fertilizer
 The main issue at hand is to understand the fertilizers and how they make plants react. Simply stating that organic fertilizer is safer for the environment and more usable by plants is a mistake. Millions of tons of manure are generated by the ranching industry. Applying these mega-tons of manure near lake or river watersheds will certainly pollute them during heavy rains. Plants will grow quickly with manure applications, but will likely have a poor fruit set and poor root systems. Many organic fertilizers are good components of an integrated fertilizer program rather than as a single component.    

                                                            Not all organic products are safe for plants at all levels. Lime is an organic ingredient, yet in the wrong place it may raise the pH of soil to hazardous levels. Blood Meal, a favorite of rose growers, can burn plant roots when used too often or at high rates. It also smells terrible, as do some other organic fertilizers. Muriate of potash or even wood ash can burn plant roots when misused, or without integration into a program of soil enrichment. High phosphate levels can tie up other fertilizer components, especially metals like iron and manganese. Any fertilizer is risky when it is misused. I believe the true issues to talk about are the amount of energy input required to make synthetic fertilizers, and the proper use of any fertilizer, organic or otherwise.

Organic materials can work wonders, if you know how to use them. People need to understand the complexities of organic fertilizers before they can be used to their full potential. It may be several times more expensive to use organic materials than the synthetic ones, but the plants may grow better, with less pollution and less energy required to produce them.

an old stand-by product,
a favorite of organic and rose growers alike
 Once again, I make a pitch to understand the techniques employed in growing plants. There is a lot of emotion being generated about "going green" and buying organic food. I ask that people do some research to check out what the true meanings of the terms are, before we pay too much attention to the "green" gardening furor.

Craig Morell
Pinecrest Gardens                     

1 comment:

  1. Hello plant guy! I am a fan of your work and have been following you for a while, I just want to tell you that you are doing a great job here so keep it up