7 Tips for better soil
Improve your soil to improve your garden
We’ve said it countless times before: healthy plants need healthy soil. If your garden is blessed with beautiful, rich, loamy soil, then good for you. If not, you might need to improve it to get the most out of your garden. The good news is that even if you have sandy or clay soil, it can be improved until it can support a healthy plant population. The golden rule of improving soil is adding organic matter to it, and there are a number of ways of doing so. Here are seven things that you can do in your garden that will make a big difference to the quality and health of the soil:
When in doubt, add compost – we should put that on a The Gardener bumper sticker. Compost is black gold for the garden, and you can use commercial compost or make your own. Good-quality compost looks like rich soil and smells like earth, with no odour of rotting or decay. The rotting or breaking-down process should already be complete, so that now the compost is full of carbon, nitrogen and oxygen. You also don’t want to be able to recognise too many bits and pieces in your compost, like sticks or nut shells, because they will actually use up some nitrogen as they break down in the garden.
If you decide to make your own compost, there are many methods and theories in doing so, but the golden rule is to maintain a good ratio of greens to browns (about 4:1) to optimise the composting process, and not to allow the compost to become too dry or wet. Read more on compost here.
Compost can be dug into the soil as a general conditioner, or it can be used during the planting process, or you can apply a thick layer (5cm) of compost on top of the soil. This will get absorbed into the soil over time as organisms integrate it. Remember: there is no such thing as too much compost!
We’ve already mentioned using compost as a mulch, and it is an excellent one. But there are loads of mulch options, both organic and inorganic. While both types discourage weeds and help to keep the soil cool and damp, organic mulches are the ones you want to use because they will improve your soil. Inorganic mulches include gravel and even landscape fabric, and
popular organic ones include macadamia nut shells, peanut shells, bark chips or wood chips, pine needles, straw, leaves, grass clippings and even paper or cardboard.
Before applying mulch, it’s a good idea to weed the area. Once that is done, a 5 – 10cm layer of mulch will prevent the majority of weed growth, and those that do make it through can be easily spotted and removed.
If you are really battling with weeds, apply a layer of cardboard or newspaper to the soil and then mulch over it. Don’t mulch right up to the stems of plants – give them a gap of a few centimetres to prevent rotting and to allow water to penetrate.
‘Hügelkultur’ means ‘mound culture’ in the German of its origin, or growing on a mound, but there is much more to it than that (and it doesn’t even have to be on a mound!).
The essential aspect of hügelkultur is that you are creating a raised garden filled with rotting wood, or wood that will rot. Generally, you dig a pit (although you can start at ground level), fill it with logs or branches and keep going until you’ve made a mound, top it with a growing medium, and get planting. The theory is that the biomass (the pieces of wood) absorb water and slowly release it to plants as it is needed. They also break down over time, making nutrients available to the plants and also creating air pockets that the roots will exploit. By creating a hügelkultur site, which is a form of permaculture, you are mimicking the natural process of a woodland, where wood and leaves are broken down and recycled by new plants.
Over time a hügelkultur site will improve the soil, and it is a great way to get rid of garden waste such as branches. You will hardly ever need to water once it is established, even in winter, and you even get a bit more space in your garden because you plant in the sides of the mound. Hügelkultur is great in areas with poor drainage as well as areas that don’t receive a lot of water or are on a slope, as water is all retained where plants can use it. It is also cheap and environmentally friendly and you can get started quickly, without waiting for the organic matter to turn into compost. And once you’re up and going, it is very low maintenance. It sounds like a winning idea to me!
4. Lasagne gardening
Lasagne is one of the world’s great pleasures, as Garfield can attest to. But it is also a gardening term and is a handy and easy way to improve your garden or establish a completely new garden bed, by quickly and efficiently building up the levels of organic matter.
In gardening terms, lasagne gardening is also called sheet composting or sheet mulching, and refers to the layers used in building up a bed. Just as there are countless lasagne recipes, there are a number of different ways of implementing this garden method, but here is ours:
Start with a double layer of newspaper or cardboard, which has a dual role; to smother any weeds or grass and to slowly break down and add organic matter.
On top of the newspaper/cardboard, add a 2 – 5cm layer of kraal manure, chicken manure or even horse manure. This stuff is full of nitrogen. Then comes a 5 – 7cm layer of straw, hay or shredded dry leaves. This can then be topped with another layer of manure or a layer of green organic matter (grass clippings, leaves, veg and fruit scraps, trimmings from the veggie garden). The brown layers should be twice as thick as the green layers. Repeat these layers, alternating between green/manure and brown, until the bed is high enough or you have run our of materials.
Water this well and then top this all off with a 2 – 5cm layer of good compost. You can plant directly into this compost layer, and the layers beneath will slowly break down to create a thick layer of beautiful soil. To maintain it, add a layer of straw or leaf mulch regularly, and it will continue to develop.
5. Food forests
This is an exciting method of gardening that is really starting to catch people’s interest. The principle is essentially to create a self-sustaining micro-climate and ecosystem that mimics nature. We will give a very simplified account of a food forest, because it is in itself a complex subject that we could (and will in the future) dedicate a long article or even multiple articles on.
A food forest, like a real forest, is made up of tall trees, medium trees, shrubs, herbs, groundcovers, root vegetables and vines (although it doesn’t have to have every one of these seven layers). They are self-sustaining and self-mulching with the leaves they produce, and they retain moisture in the soil due to the shade they create.
The goal is to create a space that includes most of the layers mentioned above so that they all contribute to the overall success of the forest. Tall trees can be nut or tall fruit trees; medium trees can be smaller fruit trees or big shrubs; shrubs can be berries or similar plants; herbs can be actual herbs or herbaceous plants; groundcovers can be anything from nasturtiums to dune spinach; root vegetables can be things like ginger or potatoes, or legumes that add nitrogen to the soil, and vines can be grapes, kiwis, granadillas, beans or peas. Fungi such as mushrooms will also appear, and will speed up the breakdown process.
Because of the density of planting, a lot of organic matter is created. If this is left to break down naturally, be it leaves or dead plants, the soil life will proliferate.
6. No-dig gardening
We have all been somehow conditioned to dig over our gardens, to rid them of weeds or incorporate compost or fertiliser. Maybe it’s because we see farmers do this with their huge tractors? Whatever the reason, all this does is help weeds to germinate by exposing their seeds to light and moisture, kill beneficial soil organisms, and reduce the amount of moisture in the soil. All that hard work, and we’re actually damaging our soil!
No-dig or no-till gardening and farming does away with this labour, and with great results. Instead of digging over the soil regularly, the soil is left undisturbed and lots of organic matter is added as a mulch. Digging is kept to a bare minimum, to make holes in which to plant.
The advantages are obvious: it is easier, it is quicker, you don’t have to water as often, there are fewer weeds, your back doesn’t ache and your plants are healthier. The cons are that you need to add a lot of compost, which can be expensive if you don’t have a big enough compost heap, and carting big loads of compost can be a big job that should be done seasonally.
If you do start a no-dig garden, you will need to be patient and give it time to get established. You will also need to build paths so that you don’t stand on your soil and compact it. But after time the soil will become softer and easier to work in, rain will sink in and not run off, taking topsoil with it, and you will be able to spend more gardening time doing the things you like doing, instead of digging soil over and weeding.
7. Cover crops
Here is a really easy way of improving your soil. A cover crop is a plant that is planted, usually by sowing seed, and it is planted to benefit the soil, not for an edible or ornamental crop. Often they are planted after your veggie crop has ended and before you plant a new one, so they are usually quick-growing plants that add value to the soil. Because your soil isn’t left bare between crops, it loses less moisture to evaporation and less topsoil due to erosion, and it also helps to keep soil life active and healthy. When they have grown and you are getting ready to plant your next crop, you dig the cover crop back into the soil as a form of green manure. This is usually done when the cover crops are flowering and have maximum nutrients, but haven’t set seed – otherwise you’ll be turning them into weeds!
There are three main groups of cover crops: grains (oats, rye, annual grasses), legumes (peas, beans, soya beans, clover) and broadleaves (mustard, alyssum), each with benefits. The deep roots of the grains break down the soil and make it softer; the legumes add nitrogen to the soil; the broadleaves germinate and grow quickly to outcompete weeds, and they are easy to dig back into the garden, where they add significant biomass.
When the cover crop is ready to be killed, you can turn and dig in the entire plant or you can cut the plants off at the base and add the leaves to the compost heap and just dig in the roots.
You can use no-till and cover crops together, but then make sure you dig in as shallowly as possible.
Once you’ve dug in your cover crop, wait for 2 – 4 weeks before planting your next harvest.