Improving your soil before planting ensures a bumper crop. Find out how to improve soil for vegetable patches, specifically, but the principles apply to any part of the garden.
If a food crop isn’t given the best possible conditions, it’s quality suffers. You won’t enjoy a think-skinned dry tomato, bitter lettuce or tough broccoli and that’s just how they’ll turn out if the soil doesn’t supply the water and nutrients they need. Veggies need full sun for all or most of the day, moisture but not wetness around their roots at all times and soil that not only contains the full range of nutrients, but also friable – that is open, crumbly and easy for roots to penetrate.
Step 1 – DIG it up
Digging aerates and breaks up soil and also lets you see what it’s made of. Unless your soil is very sandy, which will be easy to dig, most soil forms clods when you dig it over. The more clay in the soil, the harder to dig and the more cloddy it is. Dig the soil over to the depth of the blade of your spade, roughly breaking up the clods and removing any roots, stones and the bulbs or tubers of any weedy plants. use a file or angle grinder to put a sharp edge on the spade for easier digging.
Step 2 – ADD organic matter
Cow or horse manure shoveled free from farms and stables is ideal but you can also use home-made or bought compost or a mix of compost, manure and organic products such as blood and bone or pelletised chicken manure. You need quite a lot to make any difference – a 30L bag of cow manure for every square meter isn’t too much. If you have infertile sandy soil, you’ll need to add a lot of organic matter to give it body.
Organic matter improves the structure and water holding capacity of the soil, causing particles of soil to clump together into ‘crumbs’ creating more space for air and water. Organic mater is also the food for soil organisms, whose eating and excreting increases the fertility and absorbency of the soil. It’s essential to renew organic matter every time you replant the vegie patch.
Step 3 – SPREAD fertilizer
Fertilizer adds the nutrient comph that soil needs. If you add enough manure-based organic matter and reapply it every time you replant the patch, you can get away with not using fertilizer. However, sprinkling controlled-release fertilizer as you add organic matter is good insurance.
Step 4 – ADD lime
Lime or dolomite lime contains calcium, which is an important nutrient and also reduces soil acidity. If the most of your soil is acidic and as manure is acidic, too, sprinkling a handful or two of lime over every square meter once a year is a good idea. If the soil is naturally alkaline, don’t add lime.
Step 5 – DIG it through
Dig all the additives through the soil thoroughly. The finished result should be soil that is fine and crumbly. Water the patch well and let lie for a week or two. This allows soil organisms to start breaking down additives into nutrients that are more easily accessible by plant roots. Now you’re ready to grow the best vegies you’ve ever eaten.
Can’t dig it?
Heavy clay is hard to dig and almost impossible to blend organic matter through.
Use a mattock to break up the surface, then spread horticultural gypsum over it. Water in and 3 weeks later dig it again. It’ll be a little easier, but you’ll probably need more gypsum. When you can dig the surface, start adding organic matter and dig that thoroughly through. Alternatively, build a raised bed (at least 20cm high) and fill it with good quality bought soil.