Last month on Stoep Harvest, we showed you how to plan and design your vegetable garden. Now we move on to the most important ingredient in a successful garden, the soil. We will look at the various soil types and how to enrich it.
Composting is an important part of enriching the soil, so come back next month where we will cover how to make your own compost and how to use a chicken tractor.
It is still winter in the southern hemisphere, so now is the time to prepare your garden for spring planting. In South Africa, spring officially begins on September 1st. However, with the unusual weather we’ve experienced recently, the seasons all seem 4-6 weeks behind the normal schedule.
Preparing the soil is critical for the success of your vegetable garden. Some people say that ‘we are what we eat’ and we all know that our health often depends on what we eat. The same is true for the plant world – the more nutrient-rich the soil, the healthier the plants. Better soil means plants are bigger, stronger, more fruitful, and are naturally resistant to disease and even pests (pests will often prey on weaker plants).
What type of soil do you have?
There are three main types of soil. On one extreme of the continuum is sandy soil. This has large particles which means water drains quickly through the soil and the soil leaches nutrients. There is more air in sandy soil, and it is easier for roots to penetrate. This makes it good for root vegetables such as carrots and beetroot.
On the other extreme is clay soil. The particles here are much smaller and there is no space for air and therefore limited water and nutrient loss. Clay soil is frequently waterlogged as the small particles act like a sponge.
In the middle of the continuum there is loam soil. This has a mixture of small and large particles so that it is able to hold moisture without the ground becoming waterlogged, hold nutrients better, and provide an aerated and loose environment for root growth.
Compost cures all conditions
To create loam out of your clay or sandy soil, simply add lots of compost! This improves the water retention and nutrients in sand and likewise increases the drainage and aeration of clay soil. It is the solution to both extremes.
If you are in the Cape, you may have seen your sandy soil repelling water, as if your sand was made of oil. This hydrophobia is simply a case of the sand having no absorption properties and can be easily fixed as you add plenty of compost. We have seen sandy gardens instantly absorb water as soon as compost is added.
Another challenge is rock in the soil. Ideally, rock-free soil is best for growing vegetables. Where there are many large rocks, other than digging and removing the rock, a simple solution is to build upwards on top of the rocky soil. Build wooden frames on top of the rocky soil and fill with good soil. This strategy is also useful in ground that gets waterlogged.
What is your pH?
The next factor to know about your soil is the pH level. Various kits can be bought to find this out. Most vegetables like soil that is very slightly acidic, at pH 6.0 or 6.5. If your soil is more acidic than this, add some agricultural lime to the soil. If the soil is too alkaline, add some horse manure or even pine needles as these will increase the acidity.
Finally, you can prepare your soil by adding other nutrients. Bonemeal stimulates root growth and is good to add to the soil, however, make sure it is well buried if you have dogs that like to dig! Worm castings, live worms, organic fertilizer pellets, kraal manure, and other organic products all add to your soil life and will prepare your beds ready for planting in spring. (Note, it is important to let the soil settle for two weeks before planting, so make sure you get your preparation done in advance).
- Western and Southern Cape: beetroot, cabbage, carrot, lettuce, peas, radish, tomato, and turnip.
- Inland (Free State, Highveld, Northern Cape, the interior of KZN): cabbage and peas.
- Coastal KZN: bush & pole beans, cabbage, carrot, cucumber, eggplant, lettuce, peppers, potatoes, radish, squash, spinach, sweetcorn, and tomato.
Happy planting! Future topics will include pest control, composting, mulching, and companion planting.
By Sam Adams
Sam runs Living Green, an organic food gardening company in Cape Town.