One item in the garden budget that is vital but often overlooked is looking after the soil. Right up front I will say that feeding your soil is much more important than feeding your plants. No matter what type of soil you have, the basic steps are the same.
The best way to improve soil is to develop a biologically active soil. There are millions of organisms that can help plants grow, including microbes like bacteria, fungi, insects and worms. These organisms also help protect plants from pests. In addition there is a class of fungi that “extend” the root system of plants making them more drought tolerant. If these organisms are encouraged then the plants will grow better and resist disease.
So how do we encourage a biologically active soil? Firstly, we need to add organic material to provide food for the soil organisms, which in turn break it down to provide food for our plants. Secondly, we need to minimize chemical interference that can kill the soil organisms we are trying to encourage.
When installing a garden one of the most important things to do is to add plenty of organic matter. This is the best time to really set the foundation for improving the soil in your garden. Once trees and shrubs are planted it becomes impossible to dig in organic matter so we have to rely on soil organisms to do the job for us. For example, if your soil has a good population of worms, they will digest organic matter placed on the surface as mulch and pull its goodness deep into the soil, so that the soil continues to improve. However, if you do not encourage worms in the initial installation of the garden, the soil will be inactive and the mulch will sit on the surface and just rot.
Adding a lot of organic matter is one of those things that does not show immediate benefit, is not very glamourous and is therefore something that is easy to skimp on, but it is the best investment you can make to ensure a beautiful garden.
Then there is maintenance - the mulch layer on top of the soil needs to be maintained - a three to four inch layer of organic mulch will not only slowly break down to feed the plants but will also insulate the soil to keep roots cool and help prevent evaporation on the soil surface reducing the amount of irrigation required.