What's In Organic Fertilizers?

You’re on a quest to green your garden, but it all seems needlessly confusing. Whether you want a classic, green lawn, or organic food for your family, you’re likely to be adding to and amending your soil. If only you knew what to add!

Before you add anything other than compost though, STOP, get your soil tested. But it might take a little time for organic fertilizers to make sense to you – let’s get started on learning. That way you’ll be prepared.

Plant By-Products

It doesn’t sound very grand, but plant by-products make some of the best organic fertilizers. Plant by-product fertilizers include:

• alfalfa meal – pellets you often see for feeding rabbits and guinea pigs;
• corn gluten – a by-product of the corn syrup manufacturing process;
• cottonseed meal – as a crop, cotton is heavily treated with pesticides making this a less than ideal choice, and not one for your vegetable garden;
• soybean meal – somewhat expensive;
• seaweed fertilizer – my personal favorite, though I’m not sure how sustainable these are;
• wood ash – unsuitable for some soils; make sure you know the source, as you don’t want it to contain ash from treated wood.

Animal By-Products

Depending on your ethical stance, animal byproduct fertilizers may be off your list. If so, please skip down to the next section.

• Composted manure has been used to enhance plant growth since farming began. If you don’t have rabbits or chickens, you can get manure from a local horse stable, or buy composted manure in bags. Still, it could be hard to determine what the animals were fed on – pesticides are a possibility, unless testing has been carried out.
• Blood meal, bone meal, and feather meal are by-products of the meat industry. Feather meal should be less expensive than the other two and it is a slow release fertilizer.
• Fish products – a by-product of fish processing. Fish fertilizer contains readily available nutrients and is good for quick green-up on your organic lawn.

Compost and Compost Tea

Compost is the ultimate fertilizer additive for your organic garden. You can never have too much compost – most of us don’t have enough. So get started on making your own, if you haven’t already. Use Leah’s guide Basic Composting for Busy People and, if you need more information, Composting Resources.

How to use compost is a large topic all by itself. For now you need to know that if you don’t have enough you can buy commercially produced compost. The advantage of compost tea is that, compared to straight compost, the nutrients are more readily available for plant growth; it’s good when you need to give your plants, such as your lawn, a quick boost.

Mineral Fertilizers

Mineral based fertilizers can be part of your organic gardening program though, just to be confusing, they are inorganic in origin, but they are naturally occuring. They consist of minerals extracted from the earth

Some mineral fertilizers are widely available, while others are local. Their usefulness varies – before spending on these be sure to research their effectiveness and have a soil test done. Did I say that already? Mineral fertilizers include:

• granite dust – source of potassium;
• greensand – expensive, slow-release source of potassium;
• gypsum -  a widely used source of calcium;
• langbeinite -  source of potassium and magnesium;
• limestone – widely used source of potassium and magnesium;
• rock phosphate – potassium source which is slow release (only about 2% is available to the soil per year);
• zeolites – contains potassium, calcium, aluminum, and silicon.

Confused Now?

When it comes to choosing fertilizers for your organic garden, it helps to understand your options, and where each of the fertilizer components comes from. I hope you have found this guide useful.

Please do leave any questions you have related to organic fertilizers.

Photo – Lawn Strawberry by jhirtz on Flickr

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