You may be wondering, why is it important to have good soil? The reason that soil quality matters is that healthy soil can store and process more water. Poor quality, depleted soil, won’t hold water and will make it impossible for your plants to thrive and survive. They key to healthy, high-quality soil is lots of organic matter, things formed by living organisms.
Keep in mind that soil is a living and dynamic ecosystem in and of itself. That ecosystem hosts spaces in between soil particles (otherwise known as pores) that allow for passage or retention of water and nutrients. For example, fine soil particles, such as those found in clays, hold water much more readily than the larger particles in sand. The amount of available water in your soil has profound consequences for your garden. Not only will that amount effect the health of your plants and the amount of water you use in irrigation but it will help balance soil surface temperatures and regulate the heat content of the soil which in turn effects seed germination and flowering activity. Organic matter is the key to water retention and good soil health.
Organic matter can be anything containing carbon compounds. That is, things formed by living organisms. Organic matter can be anything from lawn clippings and leaves to stems and branches, moss, algae, lichens, manure, kitchen scraps, sawdust, insects, earthworms and microbes.
While native vegetation are adapted to their soils, most garden crops prefer a loamy gardening soil composed of half solids high in organic matter and half porous space and with a neutral or slightly acidic pH. This kind of soil holds water without water logging. It also allows air into the soil so that roots and soil organisms can thrive.
As an aside…you may have heard the term ‘humus’ and wondered “what in the heck is that?” Humus us basically partially decayed organic matter. It is composed of complex organic compounds that have resisted decomposition and have accumulated in the soil. Humus is another useful ingredient when it comes to water retention in the soil.
So how do you get to the perfect water-retaining soil?
While some suggest mixing silly things like anionic polyacrylamide into your soil to improve absorption and retention I suggest you simply add organic matter. This is not rocket science and there are many easy ways to get it done.
You may want to start with compost. Compost is simply organic matter that is being decayed via aerobic decomposition. Anyone can build or buy a composting device or structure and put it right to work by adding food scraps and landscaping leftovers to a pile to allow it to decay into rich, dark soil. There are numerous composting websites such as this one, Compost Instructions, that will show you exactly how to make your composting effective.
In Permaculture design however, we often discourage compost in favor of a less intensive and more effective soil building method. When you compost, you decrease the nutrients in the organic matter by allowing them to go into the air or to be leached out of the compost pile. Think of grass clippings. When you pour them on the compost pile they are green. All that green is essentially nitrogen. A few days later those clippings are brown and dry. Where did the nitrogen go? Up into the air.
So instead of composting, we often avoid the compost pile in favor of putting kitchen scraps and other organic material such as grass clippings directly into the growing area and covering it with straw or some other moisture retaining material. You will be spreading the organic matter over a wider area and letting the decaying process occur at a slower rate on top of the surface of the soil. Fewer nutrients go up into the air and those that leach out then go straight into the soil. The decaying activity – a key part of the soil ecosystem – spreads across the whole of the growing area. This is a more effective way of building your soil.
You can also simply buy topsoil, different types of ready compost or a manure mixture to get your soil where you want it to be. Just remember that, by adding organic matter to the soil you alter the amount of nitrogen and other nutrients that is available to your plants, you alter the way soil aggregates and holds water and you increase the number and diversity of organisms in your soil.
In addition to organic matter, here are nine ways to improve your soil.
- Aerate – Put simply this just means loosen up your soil. You can easily do this with a digging fork. Over time soil gets packed down and it helps to loosen it up before planting. You will need to be careful when you loosen up soil around your existing plants not to disturb any of the root systems.
- Add compost – There are lots of different types of soil. Some soil has more clay and some has more sand depending on where you live. If your soil has more clay you can add finished compost and sand to it. Aim for an equal ratio of each – clay, sand and compost. If your soil is more sandy, aim for twice as much compost as soil in your planting area. More about compost below.
- Try raised beds – Raised beds are a great tool for vegetable gardening because they make it easier to control the quality and the amount of water.
- Avoid tilling – This tip matters once you’ve already got your plants in the ground. If you avoid till the soil after planting it can destroy existing ecosystems in the soil. Try spreading compost and mulch on top of the soil.
- Use Mulch – The benefits of mulch are three-fold. First mulch can help control weeds. Second, mulch helps the soil retain water. Third, as the mulch breaks down it can feed the soil.
- Plant Perennials – Perennials have root systems that by their very nature decrease erosion and help to anchor the soil in place.
- Protect your plants from wind – Strong storms can wreak havoc on your plants and soil. If you have the opportunity to either plant something to act as a windbreak, like shrubs, or put up a fence it can help plants survive the elements.
- Don’t walk on your garden – This may sound like an obvious tip, but walking on the soil can compact the soil and make it harder for the water to get it. If you need to walk directly in your garden place stepping stones and try to minimize.
- Prevent water run off – Create permeable pathways between your garden beds to allow precipitation to filter into your soil instead of running off. Slow the water down and keep it on your land!
Take a look at this video for an example of improving your soil.
We’ve written even more tips about adding organic soil amendments to improve your soil quality.
Read more about how soil can help your vegetable garden.