Have you ever wondered why the N-P-K numbers on bags of organic fertilizer (N-P-K stands for Nitrogen, Phosphorous, Potassium) are generally lower than synthetic fertilizers? I know that I used to. Does it mean you get less nutrition with an organic fertilizer?
No, the good news is that organic fertilizers generally don’t offer less nutrition (and may offer even more). Here is why. By law, fertilizer companies can only claim the ratio of minerals that are immediately available to plants. Synthetic
fertilizers use chemically processed raw materials. They are water-soluble. This allows the plant to take up the fertilizer immediately. (And hence the bigger numbers.) Synthetic fertilizers will give a quick boost to plants.
Organic fertilizers are made from naturally occurring mineral deposits and organic material, such as bone/plant meal or composted manure. They release their nutrients slowly, over the course of the season. (Hence the smaller numbers.) In addition, organic fertilizers offer more nutrients beyond the N-P-K ratio. They can offer minerals such as calcium, magnesium, sulfur, and micronutrients such as boron, copper, and iron. Synthetic fertilizers do not offer these nutrients. Organic fertilizers will also stimulate beneficial soil microbes and improve the structure of the soil, whereas synthetic fertilizers do little to improve soil texture or stimulate soil life. And, yes, synthetic fertilizers use fossil fuels.
But you might be thinking, “Isn’t it better to give my plants nutrients quickly, as soon as possible, rather than later?” Well probably not. Not all of the fertilizer is absorbed by the plants. The excess fertilizer leaches into streams and bodies of water, causing problems such as water pollution, algae growth, and the death of water organisms. And too much fertilizer can “burn” foliage, damaging your plants and the microorganisms that live in the soil.
In this case, slower is better. If I choose to use a fertilizer, I make sure it is organic. Combine it with compost and you will be golden (or should I say green? ?)