I keep talking about dirt. That is, I seem to have a soil fixation. Perhaps that’s because gardens begin with the soil. Properly prepared soil produces healthier plants, reducing the need for chemical sprays and fertilizer, and making more efficient use of water. Last May I discussed what soil is, and how to amend it. Today I want to expound a bit on the various types of amendments. I’ll also repeat myself a bit. That sort of thing happens as one gets older.
While living along the Front Range has many benefits, our soils are really pretty pitiful. Unless you are content growing a limited number of native plants adapted to this area, you’re going to have to improve on nature. What’s an environmentally responsible gardener to do?
In new plantings, it is worth spending a little time and money for a soil test. Knowing what your soil has, and what it lacks, helps you avoid many time-consuming and expensive mistakes. Follow the test result directions to maximize fertility and soil health. There are natural materials available to raise your levels of nitrogen, potassium, and phosphorous.
Most soils in this area are deficient in organic matter. Digging in a 3 – 4 inch layer of compost, peat moss, or aged fertilizer over the area will do much to alleviate this problem. Amendments vary in their content, and it helps to understand the differences.
Bagged, dried manures are probably the most easily purchased, but are the least useful. Most packaged manures come from feed lot operations. Aside from the ethical considerations, feed lot manures have other problems. The animals are fed large quantities of salt, and this winds up in their dung. Putting all that salt into your garden soil will stunt plants. With our meager rainfall, it will take years to leach out again. Add in the plastic packaging and the transportation required, and it’s not worth it.
Manures from neighbors with horses, alpacas, etc., is a different story. Choose dung from animals that do not eat meat, to avoid recycling bacteria and other parasites. Let it age for several months to kill any existing microorganisms and to lower the nitrogen level to where it won’t burn your plants’ roots.
Manures vary. Horse manure tends to include a zillion weed seeds, while alpaca has virtually none. All those stomachs do a good job of digesting the plants. Rabbit manure is also weed-free, and can be applied straight from the hutch. Chicken manure is especially high in nitrogen, requiring thorough composting to avoid burning plants. All manures should be aged to kill any harmful bacteria before being added to a vegetable garden.
Peat moss has been accused of being environmentally unfriendly. To clarify, the bales of peat you can get at the garden center come from peat bogs in Canada. This is a renewable resource. While no process is totally with environmental impact, Canadian peat harvesting is a carefully controlled, sustainable industry. (You may not want to use something that has to be shipped this far, but that’s another issue.) At one time, Colorado peat was also available for garden use. This peat was dug out of fragile peat bogs in the mountains. It is not a renewable resource, at least in any reasonable time frame. Plus, this peat has a pH high enough to damage your garden soil. You don’t ever want to use it. If you aren’t sure where the peat you are considering came from, ask.
Peat has some advantages and disadvantages. It is very long lasting in the garden, which makes it well suited for more permanent landscaping jobs. It might lower your pH slightly, which is usually not a concern here. Peat is naturally hydrophobic, meaning it repels water. If you use too much, that could cause problems. It also tends to be relatively expensive.
Compost is my pick for best amendment. While it doesn’t add significant amounts of nitrogen, it does provide humus that soil organisms feed on. It will open up clay soil, improving drainage. At the same time, it acts as a sponge in sand, hanging onto water that would otherwise drain away. You can buy compost in bags, in bulk, or you can make your own. What a great way to recycle!
Digging destroys your soil structure, so recently dug soil needs some special care. Never walk on the soil after turning it. You will compact it to the point where nothing can grow there. If you must access the area, put down some stepping stones, or a board or piece of plywood, to take the weight of your footsteps.
With few exceptions, nature never leaves soil bare for long. Neither should you. Cover your soil with a layer of mulch or other groundcover to protect it. Mulches can be inorganic (gravel, plastic sheeting), or organic (leaves, bark, cocoa shells, etc.). Either kind can be used, but avoid the solid plastic. It’s a barrier to the air and water roots need.
By improving your soil, you create a microcosm of life under your feet. As the saying goes, feed the soil and it will feed your plants. It’s the best foundation you can offer your garden.