A Journey to Grow a Little Food Close to Home

Friday, August 20, 2010

Growing Dirt #5

Today marks the end of the 5 post series on dirt. As a last but not least, we are going to talk about poop!! Poop from animals is more commonly known as manure. Because some people don't like the idea of talking about poop (even though everybody poops), we'll call it manure from here on out.

Manure has been used as a fertilizer and soil maker for generations and it's still just as good as it was 100 or even 1000 years ago. Despite the fact that most poeple think of cows when they think of manure, all animals (yes, even people) make manure and different manures have different properties. Here you can see some of the properties of various animal manures:

You might notice that people are not listed on the chart. Human manure (or Humanure) needs to be handled very carefully because our bodies have critters living inside them (like e coli and salmonella) which help to digest our food but, when eaten, can make us very sick. Composting toilets can help. So can proper composting practices (read the Humanure book). Animal manure, on the other hand, can either be direcly added to dirt or can be added after a little prep.

This prep vs. no prep is the major distinction between animal manures. Manure that needs to sit for a little while before being added to dirt (it needs to finish breaking down) is called 'hot' manure. Chicken, horse, and sheep manures are considered hot. A co-worker had a little run-in with the effects of hot manure earlier this year. He spread chicken manure directly onto his garden and 'burned' his lettuce. The burning happens because the manure releases levels of nitrogen and ammonia which are too high for plants to process. Some manures are so hot that in the past their hot properties have used as an advantage. Horse manure was often put into a hotbed

which was basically a deeper version of a cold frame. Historical reports tell that the decomposing manure could easily heat the cold frame to as hot if not hotter than 90 degrees!

Cold manure (cow, steer, and rabbit, in this case) is not as volatile and can be added directly to a garden. It has been recommended, though, that plants grown in cold manure be allowed to grow for 90 days before handling. For hot manures, 6 months of composting before use usually does the trick. Both practices ensure that all of the nasties are gone from the manure and won't harm the humans who are eating the food.

As for the 'N-P-K' numbers in the chart up top...in addition to a good loam, water, and sunlight, plants need a couple other things to be happy. All trace minerals are good but the really important ones are nitrogen (N), phosphoric acid (P), and potash (K). Just about all retilizers are labelled this way. You may have seen a lawn fertilizer labeled 10-10-5, for instance. This refers to the ratios between the different ingredients. The numbers are important for a couple of reasons. 1. Different plants need different nutrients in different strengths. This knowledge comes in handy when rotating plants or when planting several varieties together. Your seed pack or a Google search should help you determine individual plant needs. 2. Different soils start out with different nutrient mixes and can be 'grown' to have better balances.

This brings us to the soil test. A simple kit can be picked up at just about any garden supply center. Most will test for N, P, and K, as well as ph, or acidity.

More on soil testing in future posts. For now, learn about growing dirt, test your own, gather some compost material, help it decompose, and feed your soil. After all, well fed soil means well fed plants!

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