Can you beat peat?
Photo by Ragesoss.
By Dorothy Dobbie
Sphagnum peat moss.
F
rom time immemorial, people have been using natural products to sustain and improve their lives, so it is interesting to note that we did not get around to using peat moss in our gardens until the 1960s. Peat moss has been used as a fuel since Roman times and maybe even earlier although its heat producing efficiency is only about one-tenth that of coal. Over the past few years, controversy has waged about the impact of using peat moss in horticulture because of concern about a negative impact on the environment. However only about 0.4 per cent of the 14 per cent of the world’s supply that is being used for any purpose is used in horticulture, and only 2 per cent of Canada’s reserves are mined commercially and under rules to encourage regeneration. The real issue for gardeners is whether the product is beneficial, and the obvious answer is yes, but that is a qualified yes. Peat does retain water, up to 20 times its dry weight; it traps air between its particles improving the tilth of soil, making it more friable and easier to use, especially in heavy, high-clay-content soils, and it adds substance to sandy soils. Peat is well loved by commercial growers as a seed starting medium. Not all peat is equal. The top layer of a peat bog is lighter in colour, spongy and good for water and air retention. It may contain bits of wood from roots, so is often used in larger containers. The next layer is darker in colour, more
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decomposed and finer. It is used for seed starting, and in consumer-potting materials sold in bales at garden centres. The lower level is the black material that is often used in the garden mixed with soil and other additives. There are several negatives about peat. It is acidic, with a pH of 3.5 to 4, and so is usually amended with lime. If you want to use peat to help grow blueberries or azaleas, check to see that it has not been pretreated. While peat moss will last for a few years in pots as a garden soil amendment, the life span is only about two years, so you are better off using leaves or compost. In containers, especially for indoor plants, it harbours fungus gnats. The remedy to that is to let the plant dry out, but the downside is that rehydration can be a challenge because dry peat repels water, although some suppliers add wetting agents. Peat can also carry a fungal spore that can infect humans. Sporothrix schenckii can be transmitted as sporotrichosis, which usually infects the skin through some opening or cut and, at its most serious, can result in a lung disease. Wear gloves when working with the product. Finally, peat used in patio plants has been known as the vector in fires caused by people butting their cigarettes in a dry plant container. So, what is a gardener to do? Use peat where appropriate. It is a good medium for seed starting and most commercial planters use it in their prepared containers, but know that you will have to fertilize frequently because it Issue 3
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