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The right kind of soil |
Garden plants grow in soil. What exactly is it? Soil includes rock that has been worn down into mineral particles of various sizes. Imagine your garden as a pile of boulders. Now imagine wind and water wearing away at those boulders over a very, very long time.... until, eventually, they become the soil in which your plants are growing today.
Turn over a shovelful of garden soil. If you see earthworms, your soil is healthy and "alive." Living creatures add humus to the soil, make nutrients available to plant roots, and help control harmful fungi. Though soil may have started out as solid rock, it's usually easy to work by the time we put a shovel to it. That's because a shovelful of soil is only about half mineral particles; the other half is almost equally divided between air and water. Only a very small amount is organic matter or humus (decaying plant material, for example). |
Besides minerals, air, and water, your garden soil comes complete with living creatures. The most visible one is the familiar earthworm, but besides a few hundred of these, the top 5cm of a square metre of soil may include a million mites and mitelike creatures and over 10 million nematodes and protozoans! These creatures all help keep the soil healthy. They process minerals to make them available to plant roots; they keep harmful fungi under control. Their waste products (and later on, their dead bodies) form humus, a soft, blackish brown material that improves the structure of any soil.
If you are growing plants in pots, you
should not use ordinary garden soil. Special mixes can be
bought from nurseries for starting seeds, or for pot plants.
These let water drain through more freely, and often contain
special nutrients to help the plants grow. Here, seeds are being planted in small
pots, so that each plant can develop a healthy root
system. Later on, when the plant has started
forming mature leaves, and it has a healthy root system that
nearly fills the little pot, it can either be transplanted
to the garden, or it can be "potted up". Potted up means
that the plant is moved to a slightly bigger pot, so that
the roots have more room to develop. It is important not to
make too big a jump in sizes when potting up a small
seedling. Your garden is a lot more effective at
growing plants if it is built up with humus or compost,
which is plant material that has rotted down. When plants
die, their remains help to make the soil better at growing
other plants.