Fertilizer is one of things that can divide a group of otherwise congenially gardeners into two distinct camps – for and against. Knowing full well how crappy our Colorado soil really is, we all know we have to do something to support our soil. That list of somethings could include:
- Composting kitchen scraps and apply compost to garden
- Applying aged chicken manure to garden soil
- Mixing organic matter into soil
- Sheet mulching with nitrogen rich leaves (think comfrey)
- And last but not least, fertilizing
The controversy over fertilizer is contentious for a few reasons, and those reasons (though subtle) make or break the argument. The big no-no in fertilizing in the organic gardening/backyard farming/permaculture world is chemical fertilizer. Chemical fertilizer is fast, cheap, and effective. So what’s the problem? Chemical fertilizer does not help your soil in the long run, and may in fact damage your soil over time. Additionally, chemical fertilizer is made from fossil fuels, so at their core they are unsustainable.
Organic fertilizer on the other hand can support the health of your soil, and can provide micro nutrients not otherwise attainable for your organic garden. I have heard the argument that organic fertilizer is sustainable, but I don’t completely buy-in to that statement. Bat guano, though renewable, may not be sustainable at the harvest rates currently being practiced. Some of the other ingredients come from CAFO’s (concentrated animal feeding operations), meaning there are deep ethical concerns there as well. So while organic fertilizer can be a benefit to your garden, use commercial products sparingly. You can make your own fertilizer from comfrey or chicken manure, though they tend to be not as well rounded as the product pictured above. We’ll cover comfrey tea and composting chicken manure for homemade fertilizer in later posts.
I don’t use commercial fertilizer often (even organic), but once a year a shot of calcium and magnesium is a welcome addition to my garden – my tomatoes thank me for it. The other nutrients (NPK) I can usually keep in the soil, but it is easier to drop all of the nutrients into the soil in a single shot. The process of applying a powder based organic fertilizer is pretty straight forward – sprinkle the fertilizer around the plant, rake in with a hand rake, mulch, and water.
I tend to fertilize after hard or sustained rains, as the water can move nutrients away from the plants; a dose of organic fertilizer can help to replace the nutrients and keep them in the soil around the plants for the remainder of the summer. Many fertilizer brands recommend using their product once a month, but I think that’s overkill. If your soil is in good shape, monthly applications of fertilizer are probably a waste of time and money. With the fertilizer down, I’ll water gently so I don’t inadvertently cause the nutrients to move significantly. This application is the only one I’ll do this year; I handle my soil differently in the fall (more on that later).
I do recommend using fertilizer, but with several caveats. Only use organic fertilizer, use the product sparingly, build your soil through compost, and supplement for nitrogen with cover crops, comfrey tea, and/or aged chicken manure. Using a combination of methods will increase your soil’s tilth and nutrient profile, and ultimately is a more sustainable approach.