Chemical Fertilizer
Is it ever appropriate to use chemical fertilizer? maybe, sometimes, yes?
Chemical fertilizers are a synthetic source of nutrients. When you need nutrition and fuel, you don't eat a vitamin, you eat real food. It is usually best to do the same for your plants. But chemical versus organic fertilizer is a somewhat complex issue. Using chemical fertilizer is not necessarily bad, if you understand how both types of fertilizer work and use them properly.
"Chemical" or synthetic fertilizers are often derived from naturally occurring mineral deposits, but they go through a manufacturing process. The nutrients are very limited, typically nitrogen, phosphorus and potassium, and the processing allows the nutrients to be readily available for the plants to use. But the nutrients are not retained in the soil so you wind of fertilizing frequently. Using a slow release formula can improve the situation, making nutrients available for a longer period as the plant needs them.
Our greedy grass lawns present the most common use for synthetic fertilizers, however our edible gardens present another common opportunity to occasionally use chemical fertilizers.. Lawn grass as well as some vegetables do quickly deplete the soil and often needed nutrients are not available. Fertilizer manufacturers keep this in mind, offering products specific to certain plant needs. Chemical lawn fertilizers are formulated for the perceived needs of lawn grass: quick uptake, greening and fast growth.
When it comes to my lawn, I generally fertilize in very low doses, applying minimal nitrogen. My intention is not to make the grass very green and grow very fast, I just want a strong and healthy lawn. Fast growing frequently mowed grass is not healthy at all and requires constant re-feeding. Managing the health of your lawn is much easier once you understand the qualities of fertilizer available, whether chemical or organic.
Many of the negative effects of chemical fertilizers are learned through large scale farming, landscape turf management, and raising nursery crops for garden centers. But what is learned by big agriculture can be applied in our own back yards. We have learned that chemical fertilizers release quickly and can be taken up in excess by plants, causing burning. The burning is actually caused by the high salt content of processed fertilizers. Water soluble fertilizers are quickly leached out of the soil by rain or irrigation specifically because they are soluble and leached away with the water. High nitrogen is a common problem with chemical fertilizers, resulting in rapid growth rather than strong healthy growth. When that nitrogen is used up, you are compelled to use more…and more…a vicious cycle.
Ideally we should be feeding the soil, so that the soil can feed our plants. In our produce gardens feeding the soil is relatively easy by incorporating organic materials each fall. But we sometimes need to supplement feedings through the growing season and our lawns of course need to be fed. Organic fertilizers typically have relatively low amounts of nutrients and are slowly released by soil organism activity. But they are not salt laden and over time improve soil structure. Organic fertilizers will cost more as they contain less nutrients pound for pound, however your plants will derive greater benefit in the long run and not require the repeated applications that chemical fertilizer demands. Fortunately organic fertilizers are becoming more readily available all the time so they are also getting more cost competitive. Organic Lawn Food is becoming more common also, but do beware the term “natural”. Read and compare the packages and ingredients of organic vs chemical to be sure you are getting good organic ingredients.
Take the time to understand when it is appropriate to use a chemical fertilizer and why, but also when we understand the why we can often find a natural organic alternative. Understanding the nutrient source for synthetic fertilizer can also help you to decide which fertilizer to use, so read the labels.
In cold weather organic fertilizers may not be very effective sine soil microbes are less active. Their activity converts nutrients to usable form. Nitrates in synthetic fertilizer also need microbe activity, higher levels of nitrogen may be required if the source ingredient is nitrates.
Nitrates are taken up quickly by plants for quick greening.
Urea fertilizer is a processed form of ammonia and requires a good population of soil microbes to process it for root absorption.
In warm weather Urea nitrogen in a blend will green lawn up quickly.
Insoluble or slow release nitrogen gives your lawn the longest lasting green.
Many chemical fertilizers are highly soluble and can make it too easy to over fertilize and damage plants or the lawn.
Many chemical fertilizers contain large of amounts of salt or salt derivatives. When you “burn” your plants or grass, it can often be attributed to the high salt content creating an imbalance in the soil.
Fish emulsion is an excellent organic alternative for fast acting nutrients, lasting a couple of weeks to be used by plants.
Blood meal is a great organic for higher nitrogen that is a bit slower releasing, over 2 to 6 weeks.
Bone meal and kelp are organic sources high in phosphorus and potassium.
Organic fertilizers do not form a crust on the soil and improve water absorption in the soil.
Organic fertilizers actually feed the beneficial soil microbes, improving the soil structure
Sandy soil will not retain nutrients well so ammoniacal nitrogen is released slower than nitrate nitrogen so it won’t get washed out of the soil.
In hot periods fertilizing is often wasted because you may be watering heavily, flushing the nutrients out. Same applies to prolonged periods of rain. Fertilizer is best applied before a light rain or irrigation, just enough to soak the materials into the soil. Whatever fertilizer you choose, big ag has certainly taught us that overfertilizing and high nitrogen contents are not good for our plants, the soil or the environment.
If you choose chemical fertilizer, at least use a slow release formula. Find a high quality pellet that combines all the nutrients into a single pellet for even application. Such fertilzers are more expensive, but you will have to fertilize less often since it is much more effective. Better yet, choose the high quality nutrients or organic amendments and fertilizers for strong and healthy plants and lawn.
There is a lot to learn and understand about chemical and organic fertilizers, but just start by paying attention to the ingredients on the package. When you make a decision to use a synthetic fertilizer, make it an informed decision and apply it properly. Understanding and using organic nutrients is a bit more straightforward and might be an easier place to start learning, certainly better for your plants and soil!