Understanding Fertilizer

Today on the blogging A to Z challenge, my topic is Understanding Fertilizer – for the letter U, of course. C’mon, what did you think it would be? Is there any vegetable, fruit or edible plant that starts with U? I couldn’t find any.

So I’m searching for the perfect photo and I think: fertilizer. Cows.

Yes, I’ll post a picture of cows.

Then I thought, “Who the heck wants to look at pictures of cows?”

So while tulips don’t have anything whatsoever to do with understanding fertilizer….they’re a lot prettier than cows.

On to today’s topic: fertilizer.

Fertilizers can be organic or inorganic, manufactured or natural. Basically, all fertilizer is something added to the soil to provide food for plants.

Think about food for a minute. You probably remember from health science class years ago that people need protein, fat and carbohydrates to live. Plants need three things too: nitrogen, phosphorous and potash. Other macro nutrients include calcium, magnesium and sulfur. But people also need other things in their food to be healthy: vitamins and minerals. Plants need many micro nutrients such as boron, iron, copper, and more to stay healthy, too.

How much a plant needs depends, of course, on the plant. Plants use their roots to absorb water from the soil; water contains the vital elements they need to live. When the elements are unbalanced, plants either cannot absorb enough of one, or they aren’t getting enough of another element from the soil. Diseases or weakened plants are the result. Plants can only absorb elements that have been released into the soil, whether from organic sources, such as compost, animal manures and cover crops, or from inorganic sources, such as commercially packaged fertilizers. Organic fertilizers tend to break down slowly, while inorganic fertilizers provide nutrients much more quickly to the plants. That’s why it’s relatively easy to over-fertilize with inorganic fertilizers while it’s hard to over-fertilize with compost and other organic fertilizers.

What Is Compost?

Compost is an organic fertilizer made from manures, the decayed remains of plants, and sometimes other materials too, such as paper or egg shells. In nature, leaf mold covering the ground decays and provides abundant nitrogen and other elements to the roots of plants. Animals poop on the forest floor, and this adds manure to the soil. In our gardens, we add compost or other fertilizers to build up the soil faster than nature can through the cycle of the seasons.

Synthetic (Man-made) Fertilizers

Man-made fertilizers are manufactured into chemical formulations that provide a very specific amount of nitrogen, phosphorous and potash. The three numbers on most fertilizer bags indicate the amount of N (nitrogen), P (phosphorous) and K (potash – K is the symbol for potassium on the periodic table of elements). Fertilizers are “balanced” when the numbers are the same: 10-10-10, 5-5-5-, etc.

Nitrogen generally “greens” leaves, so fertilizers with a high “N” level are usually for leafy plants such as grass. The middle number is to boost bloom production, while the last number is said to build healthy roots. I just did a quick, random search for lawn fertilizers and found a Scotts product that is 26-0-3, which doesn’t surprise me. The “26” indicates that the bag has 26% available nitrogen, 0 available phosphorous, and 3 percent available potash. The other materials in the bag are filler materials.

Should You Use Fertilizer?

Probably, but the question is better asked, “Which one should I use?” And that depends on your garden and your aims. If you’re an organic gardener, you’ll probably want to start a compost pile, and spread compost on your vegetable beds during the winter and spring. Here at Seven Oaks, we add compost to all the vegetable beds starting in March to replenish the soil.

But we also add inorganic fertilizers, too. Surprised? I do add 10-10-10 vegetable garden fertilizer to the asparagus and strawberry beds, and when the tomatoes are ready, I add 10-10-10 and a sprinkle of Epsom salts to the planting holes. My tomatoes still tend towards blossom end rot, and the little boost of calcium plus the nutrients from the fertilizer seem to help. We also add lime to the soil to increase the pH; if the pH levels are off, the nutrients may be in the soil but the plant may not be able to access them.

Your best step each spring is to bring your soil into your local garden center or Cooperative Extension office for a professional soil test prior to planting. A soil test is conducted in a laboratory and there is a small fee for the service, but it is well worth it. The results include the analysis of your particular soil and include recommendations as to what to add to the soil to improve it. The results will tell you exactly what to add to make your soil welcoming for the particular plants you wish to grow, whether it’s a rose bush or a tomato plant.

For more information, please see:

And yes, at last: COWS. Picture taken by me in January of my neighbor’s beef cattle.

You knew there had to be cows in this post, right?