The Organic Way to Fertilize your Garden
Learn to imitate nature when it comes to nourishing your garden
Rock Fertilizers and Manure
The most efficient way to fertilize is to imitate nature. Soil originally came from the rock. Since soils and plants evolved at the same time, using the minerals from rocks will feed them when they need the nutrients. The warmer and moister the atmosphere, the faster nutrients will become available to the plants and the better they’ll grow. And there’s no problem with an excess supply that might harm plants.
Many organic producers swear by rock powders. When you read about the extraordinary results produced by them, you realize that they are among the best of organic fertilizers. Any kind of organic matter is going to improve your soil’s capacity to retain water. They will also keep nitrogen in the soil and make nutrients available to plants.
All About Rock Fertilizers
Rock fertilizers provide trace elements to the soil as they break down slowly. You should apply them with organic matter since they do not supply any nitrogen. They last from 5 to 10 years.
Phosphate rock is a source of phosphorus and trace elements including zinc, boron, iodine, iron oxide, iron sulphide, calcium fluoride, calcium carbonate, and manganese dioxide. It’s not soluble in water but stays put in the soil so it’s always available for use when the roots finally reach it. Superphosphate is treated with sulphuric acid. This makes it more soluble but also more expensive because it uses so much energy in production. It’s easy, of course, and that makes it very tempting. It can cause imbalances in soil microbes and a build-up of salts. I used it with great abandon until I found this out.
Granite dust is an excellent source of potash. It has trace elements and is a lot cheaper than chemical potash fertilizers. It won’t change the pH and is slow to release. You can use it as a top dressing.
Potash rock contains potassium plus a wide variety of trace minerals. Apply with organic material straight into the soil or the compost heap.
I use composted sheep manure, which has a higher nitrogen content than cow manure – sheep digest more efficiently than cows. Some organic gardeners don’t like the idea of using any kind of animal by-products, though this hasn’t bothered me so far. We now know, however, that the gases produced by cows burping methane are adding to the greenhouse effect.
There is a never-ending supply of animal manure: one cow will produce 27,000 pounds (12,250 kilograms) a year of which only about a third is returned to the soil without being damaged. Manure contains a high content of bacteria.
Cold manure (cow, hog manure) has high water content and ferments slowly.
Hot manure (sheep, poultry, horse) is richer in nitrogen and more easily fermented. These should all be well rotted. There are now sources for goose, chicken, and mushroom manure. Check your source to see how it’s produced.
Worm castings are among the most gorgeous-looking and best stuff to use on your soil. They are richer in calcium, potassium, and phosphorus than any other organic product.
Rodale’s Encyclopedia of Organic Gardening stresses that it’s pointless to make comparisons between the NKP of synthetic fertilizers and manure. Manure is far more valuable: it provides trace elements not found in the synthetics, as well as organic matter necessary to the life of the soil. Organic matter turns into humus. Humus makes nutrients available to plants.
Fresh animal manure can burn plant roots. It should be well composted to make it safe and to destroy any weed seeds.
Manure Teas, Fish Emulsion, and Foliar Fertilization
When to apply manure
Spring: Add it as you prepare your beds. You can apply it to sod before a light rain, but not when you’re expecting heavy rain.
Summer: Side dress near plants; top-dress around plants when you have put them in the soil.
Winter: Add manure to the extra leaves in plastic bags; then add a bit of soil, moisten and tie up the bags. Store in a work shed. In spring, you’ll have excellent compost.
It must sit and ferment properly. Put chicken manure in a bucket of water. Strain and put the solid wastes into the compost and the liquid into a bottle. Measure about 5 inches (12.7 centimeters) from the edges of the lateral branches of the plant, and make a little channel with a trowel. Add the liquid to the channel. Tomatoes love this treatment. So does just about everything else.
Fish Emulsion Fertilizer
Make your own fish emulsion: put fish scraps in a large container and add water. Cover top with wire screening to keep out animals and insects; put in an isolated location to ferment for 8 to 12 weeks. This stuff can get pretty high – add citrus oil or scent to mask some of the odor. When it’s finished, a layer of mineral-rich oil will float on top of the water, and the fish scales will have sunk to the bottom. Skim off the oil and store it in a special container. Dilute 1 cup (250 milliliters) in 5 gallons (22 liters) of water. It’s rich in nitrogen, phosphorus, and trace elements, but low in calcium.
Dried blood is 10 to 12 percent nitrogen. Steamed bone meal is 1 to 3 percent nitrogen, 10 to 15 percent phosphorus. Rawbone meal is richer in nitrogen –3 to 6 percent – than steamed, but it’s slower to decompose.
Hoof and horn meal is 10 to 16 percent nitrogen and about 2 percent phosphorus.
If you have meat scraps and fat, or fish scraps: bury deeply to keep out of the way of animals but within reach of mature plant roots.
Also, look for products based on composted manures and natural minerals in pelletized form, which condition soil and provide nutrients. These products won’t burn plants and are environmentally safe.
If your soil hasn’t had time to build up enough organic matter, you may need to do some short-term foliar feeding. This is feeding plants through their leaves by spraying. Use this method if there’s been a heatwave or you haven’t been able to water regularly. As well, use when plants are flowering or setting fruit. Spray in the morning when the plants are getting revved up for the activity and it’s fairly calm. Use a kelp-based product derived from marine plants.