The four phases of soil management

I divide soil management into four phases: the first phase is testing the soil; the second involves the general soil conditioning and replacement of nutrients with organic matter; phase three involves the application of fertilizer; the fourth phase covers more specialized application of fertilizers for specific plant needs. If you have moved into an established garden that is obviously growing good crops, or if you have decided to convert to organic methods and there are no nutrient deficiencies showing up in your garden, start with the second phase. However, unless you know the acidity or alkalinity, or pH value, of your soil, you should test it before you start.

1 Analyzing your soil

If you are starting out, especially on virgin soil, it is a good idea to have it tested at the outset so that you know where you stand. Soils that have been uncultivated for many years are often grossly deficient in one or other of the elements necessary for healthy plant growth. Chemical growers would then repeat this soil test every year using sophisticated equipment to ascertain the exact requirements of the next crop. I have never believed that gardeners, however diligent, need to get involved in this. Once you know what you are working with, I don’t think that it is necessary; annual home pH testing is sufficient. It is best to send a sample of your soil away for professional analysis. The kits for testing nutrient levels in soil that are available to amateur gardeners are not accurate enough to be worthwhile. Used regularly, they will indicate a trend but no more than that. There are plenty of reputable companies who will analyze your soil. You will find them advertised in gardening magazines. They will be able to tell you the exact chemical makeup of your soil and, if there is a deficiency, exactly how much fertilizer you need to use to correct it. Remember, though, when you send the sample, to ask them to recommend organic fertilizers.

2 Using soil conditioners

This stage deals with the general soil improvement and replacement of plant nutrients removed by previous crops. It is here that there will be variation because it depends on how much, and what type, of organic material you have available to you. First of all, it should be taken as given that all organic material not actually used in the kitchen is returned to the soil as compost, and that this should be supplemented by manure or some other purchased soil conditioner, as necessary. Organic matter should be dug in during the fall and spread over the soil as a mulch in the growing season. This will increase the water-holding capacity of light soils and open up very heavy soils, as well as supplying all the nutrients. If you can put sufficient organic matter on to the soil, there may be no need to add any concentrated fertilizers. However, it is difficult to define “sufficient” because the amount needed depends entirely on your soil, the weather, the plants you wish to grow, and so on. You need to have a great deal of compost and/or manure if you are going to avoid using concentrated fertilizers completely.

3 Adding general fertilizer

Not everyone can get sufficient supplies of manure or compost. This is, therefore, where concentrated fertilizers come in. If, for any reason, the manuring falls below the recommended levels, you will have to make up the nutrients “out of the bag.” Use a general fertilizer such as blood, fish, and bone meal or pelleted chicken manure. The application rates vary according to the soil and the plants you want to  grow, so I have made recommendations in the relevant sections of the book. In fact some crops, for example peas, can generally grow quite well without the addition of fertilizer, so there is no need to apply it. Others, such as potatoes, will need extra. Most fruit trees and bushes will need fertilizer in the spring whether or not they are mulched with manure or compost, as will the ornamental garden.
Where any trace element deficiencies have occurred in the past, I recommend that you give the soil a light application of kelp meal or calcified kelp pellets at the beginning of each season to make sure it does not happen again.

4 Using specific fertilizers

Some crops always need special treatment even when the manure and fertilizer levels are sufficient to start with. If, for example, you are growing tomatoes in the greenhouse, they will benefit from extra feeding and a potash fertilizer to encourage flower and fruit formation. Leafy plants that remain in the ground for a long time, like spring cabbage, may need some extra nitrogen fertilizer towards the end of the winter. Plants such as raspberries are particularly prone to iron deficiencies when grown in chalky soil; this can be corrected by spraying and liquid feeding with kelp (seaweed) fertilizer. It is a good idea to apply extra phosphorus, or phosphate, before planting trees or sowing, to encourage root growth.