A Guide on Organic Fertilizers

You know you want humus or organic matter and also that other nutrients are necessary for soil and plant health. But before you run down to the garden center, let's consider some alternative low-cost soil
amendments, where you can get them, and how they will help your garden.

Compost. Your own backyard is the best and cheapest place to find this valuable soil amendment . You also will find it in the garden center's soil amendment section. Also, cities and counties are getting into the act with community composting. You can find huge heaps of the stuff near your local trash dump. Bring your own containers or a pick-up truck, and get your share for nothing or a nominal fee.

Mushroom compost. If you happen to live near a mushroom grower, they are an excellent source for low-cost or free compost. Mushrooms are grown indoors in huge containers filled with fine, dark, crumbly compost. Before growers plant mushroom spawn in containers, they steam-sterilize the compost. After a couple of months, growers harvest the mushrooms and clear out the bins. This used compost is still rich in nutrients and organic matter. A few little mushrooms may pop up, but since you know they are an edible variety, eat up.

Sewage sludge. Plants treat sewage for disposal using two methods, anaerobic digestion and air activation. Digested sludge is much lower quality as a fertilizer than the activated type. Activated sludge is usually much more expensive. Either type of heat-treated sludge is safe to use around your yard and garden. Inquire at your local treatment plant.

Green manures. When you spade green vegetation into the soil, you add precious organic matter, nutrients, and moisture. Green leaves, weeds, grass clippings, and cover crops such as clovers, buckwheat, rye, and oats return nitrogen, carbon, trace minerals, and other nutrients to the soil when turned under. Legumes, such as clover and alfalfa, make exceptional cover crops because they take nitrogen from the air, and convert it into a usable form for plants. One word of caution: If your plants go to seed, don't turn them into your garden soilunless you want more of them.

Animal manures. Where there are animals, there will be manure. The first rule is never use cat, dog, or swine manure in your garden. These types of manure harbor parasites and disease organisms that can be harmful to your health.

Racetracks, livestock breeding farms, dairy farms, rabbit runs, poultry farms, petting zoos, and non-petting zoos often are overjoyed to have someone actually volunteer to haul the manure away! Most manures should not be used fresh in the garden; salts will burn plant roots. Compost it first, or spread it over the soil in the fall so it has time to mellow.
Rendering plants. Organic gardeners are familiar with additives such as blood meal (rich in nitrogen), hoof and horn meal (high in nitrogen, phosphorus, and calcium), and bone meal (rich in nitrogen, phosphorus, and calcium). These are by-products of the slaughtering process and originate at rendering plants. Purchased in small quantities, these products are usually quite expensive. Most rendering plants sell these only in bulk, such as 25-ton tractor/trailer loads. Make friends with a plant worker who may be able to get you a smaller quantity!

Restaurants. Coffee grounds from espresso bars or coffee brewers are a good source of nitrogen. Ask the brewer to empty coffee grounds into a container for you to pick up once a week. The grounds are fairly acidic and useful in lowering pH levels when heavily applied.

Lumber mills. Sawdust is the by-product of turning trees into boards. Composed of cellulose, sawdust is a good form of organic matter for your garden. Don't add more than 2 inches each year as it requires a lot of nitrogen to decompose. For each ton of sawdust, a garden burns about 31/2 pounds of pure nitrogen. Offset this by adding 17 pounds of ammonium sulfate, 11 pounds of ammonium nitrate, or 8 pounds of urea. Avoid cedar sawdust, because it is toxic to some seedlings. Alderwood dust decomposes more quickly than others, such as fir or hemlock.