About Fertilizers: In this section, we present an introduction to fertilizers (often just called "fert" in farm jargon) and how they’re administered. In the Organic Fertilizer section, we delve deeper into specific products.
Granular: Granular fertilizer is the standard fertilizer that most people think of when they think of fertilizer. It comes in little grains of pelletized product. It typically comes in bags ranging from 1-50 pounds. It can be worked into the soil through tilling. It can also be used as a sidedress, which just means the product is placed on top of the soil above the plant’s root zone. As the plants are watered, the granular product slowly releases nutrients.
Granular fertilizer can be administered with a push-spreader on wheels, a hand held spreader for smaller applications, or you can save yourself the expense and just do it by hand out of a bucket.
Liquid: Liquid fertilizers are just as they sound. They are a concentrated liquid product that needs to be diluted with water. They come in quart to gallon size containers, and can also be bought in 55 gallon drums (though I’ve never seen this in an urban setting). Some of the common liquid fertilizers are liquid fish, liquid seaweed, and liquid seaweed fish. Liquid fertilizers can be hand-watered or administered with a backpack sprayer*.
Foliar: Foliar fertilizing means to fertilize a plant by spraying the leaves with a mist of fertilizer, typically very dilute. This is particularly helpful for seedlings when plants haven’t established an extensive root system yet. The au natural farmer loves foliar feeding; whereas, scientists have yet to establish the efficacy of it (especially for nitrogen). Personally, I’ve literally seen a field of tomatoes green up before my eyes after a foliar feeding of fish fertilizer. For seedlings, a hand or pump sprayer will normally suffice. For field applications, a backpack sprayer is necessary. Be forewarned, foliar fertilizing can burn leaves when sprayed at full strength, or when using synthetic fertilizers, or when sprayed in the sun. Therefore, try to foliar feed on a cloudy day with dilute, organic fertilizers.
Teas: Teas come in two basic forms, overnight-steeped and brewed. An overnight tea is exactly what it sounds like. You make a tea with a granular fertilizer. This is as simple as putting the granular fert in a bucket and filling it with water. This steeps overnight (or even just a few hours), and the resulting liquid is used. Essentially, the water dissolves/solubilizes the nutrients such that they are more quickly accessible to the plant than they were in a granular form.
The brewed teas may seem eccentric and are popular with permaculturists. I include them here because folks in Cleveland use these techniques. By no means are these exhaustive instructions, instead there are books and the Web for that. The most common brewed tea is compost tea. Compost tea is basically a bucket with finished compost, molasses, water, and aerator (often an aquarium aeration stone) in a warm place. Over the course of several days, the good microorganisms from the compost grow in the solution, feeding on the molasses. This nutrient solution is packed with beneficial microorganisms, which is then used to fertilize your plants.
*A Cautionary Word about Backpack Sprayers
Backpack sprayers scare people. Your neighbor may smoke cigarettes like a chimney; eat fast food like it’s the only option on Earth; douse the fence line with glyphosate; and have a car leaking oil like a geyser. But as soon as you put on a backpack sprayer, they become an environmentalist. Be assured that any time you use a backpack sprayer in a neighborhood setting, there will be at least one person badgering you about what it is exactly that you are spraying. In my circumstance, it’s generally been fish fert, which is easily discernable because it reeks like fish. But even after explaining and offering a sniff test (which shouldn’t be necessary because aerosolized fish over a 5,000 square foot area does in fact smell like fish), you may still get the evil eye. Just be prepared to do some clarifying…over and over again.