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Soil improvement is a general term to describe the process of modifying a soil to have better characteristics for plant growth and health. Soil improvement can be achieved in multiple ways, including regularly adding organic matter, applying wetting agents, improving drainage and adjusting the pH.
No matter what type of soil you have, you can improve its quality.
Organic matter comes from living things and includes both animal and plant material. Examples of organic matter from animals include manure and blood and bone fertiliser. Examples of organic matter from plants include compost and mulches. Organic matter in the soil has multiple benefits:
An easy-to-use and apply source of rich organic matter is Yates Dynamic Lifter Organic Plant Food. It’s a blend of composted and concentrated chicken manure, boosted with the goodness of blood and bone, fishmeal and seaweed. It can be mixed into the soil whenever planting new plants, or regularly applied around the root zone of established plants.
Organic matter naturally breaks down in the soil and should be regularly replenished.
To keep your soil healthy and alive you need a good balance of soil organisms, like earthworms and beneficial microbes (these include various fungi, bacteria, archea and protozoa; they all have their place in a thriving soil ecosystem).
Earthworms are great for the soil. They create tunnels for good soil aeration and feed on decomposing organic matter making the soil rich and fertile. But just having Earthworms doesn’t mean that your soil is as healthy as it could be. You also need other beneficial soil organisms - like springtails, ants, centipedes, and flatworms.
The soil area immediately around plant roots is called the rhizosphere. The rhizosphere of a healthy plant is especially rich with microbial life. These microbes are busy cooperating with the plant, either by fixing nitrogen or breaking down plant litter and dead organisms into nutrients for the plant. Plants can make their own food from the sun, but they can’t convert essential nitrogen by themselves, they rely on microbes to do it for them. Plants depend on soil microbes to survive!
Likewise, don’t be alarmed if you find mushrooms or other fungi in your garden or compost. Mushrooms are the fruiting bodies of fungi that break down woody material and are vital for the health of your garden.
So long as you’re improving your soil, the beneficial soil organisms will always follow.
Compost your kitchen scraps, lawn clippings and garden prunings to create an additional source of organic matter. Home-made compost can be mixed into the soil to boost the organic matter. Here are some handy tips on how to make compost.
Soil can be divided into three different types. The type of soil relates to the size of the soil particle. Listed smallest to largest are clay, loam/silt and sandy soils. This is also referred to as 'soil-texture' because it affects how the soil feels.
Sandy soils contain large particles with large spaces, called pore spaces, between them. They drain readily, have good aeration and are easy to cultivate. They're often called ‘light’ soils. However, very sandy soils are not effective at retaining water and nutrients.
Clay soils are made up of small particles, with minimal spaces between those particles. They store water well, often too well for good drainage and aeration. Clay soils can be difficult to dig when they’re too wet or too dry and are often referred to as ‘heavy’. Clay soils are able to hold good amounts of nutrients.
Loam soils fall between the extremes of sand and clay and are mixtures of coarse and fine particles. They're divided into categories such as sandy loam (more sand than clay) and clay loam (more clay than sand).
You can help identify the type of soil you have in your garden by how it feels in your hand when its slightly moist.
Sandy soil is often lacking in organic matter. The regular addition of rich sources of organic matter, such as Yates Dynamic Lifter Organic Plant Food, will boost the nutrient and moisture holding capacity as well as improve the structure. Organic matter will also encourage increased populations of earthworms and beneficial microorganisms.
Clay soil contains closely packed small particles. This can make it difficult for plant roots to grow and moisture to move through the soil. Adding organic matter to the soil helps to bind clay particles into crumbs and open up the structure. This allows easier root growth and better aeration and drainage. Add organic matter to clay soils by mixing Yates Dynamic Lifter Organic Plant Food into the soil whenever planting. Yates Dynamic Lifter can also be applied over and around the root zone of existing plants. This should be done several times a year to top up the organic matter levels in the soil. The earthworms that feed on organic matter also help to aerate and loosen clay soils, via the tunnels they create and their excretions (casts).
Gypsum can also be added to clay soil to help improve the structure. However, it takes months for it to help soften clay, and only works on specific clay soils (sodic soils).
It’s important to note that clay soil should not be dug when it’s wet, as this can adversely affect the structure.
Avoid planting into very clayey soil as most plant roots will rot. However, if you really want to plant in that spot, bring in some garden mix to raise the soil level up. This can be done as a raised garden bed, or a gently sloping mound. Trees need at least 45 cm deep soil and most other plants will need 35 cm. Lawns need at least 15 cm deep soil but don't use garden mix, get a sandy-loam turf underlay mix instead.
Soil pH is the measure of how alkaline (sweet) or acidic (sour) the soil is. Soil pH is on a scale of 1 to 14. Most soil pH levels sit between 3.5 to 10, with 6.5 – 7.5 being considered neutral. Most plants thrive in a neutral or slightly acidic pH but suffer when the soil is too alkaline or too acidic. Soil pH affects a plant’s ability to absorb vital nutrients from the soil. For example, alkaline soil restricts the availability of the nutrient iron. A soil that is too acidic affects the availability of phosphorus and calcium.
You can test your soil’s pH using soil pH test kits, which are available in hardware stores and garden centres. It’s best to take a few samples from different places around your garden. Once you know your soil pH, you can take steps to help bring the pH closer to neutral.
If your soil pH is below 6.0, then you'll need to increase it (make it more alkaline). Adding lime (calcium carbonate) or dolomite (calcium carbonate and magnesium carbonate) is the most effective way to fix soil acidity. An easy way to add lime to the soil is with Yates Hydrangea Pinking Liquid Lime & Dolomite, which is a mix of calcium carbonate and magnesium carbonate. Apply every 3-4 weeks until the desired pH is reached.
There are some plants that prefer growing in soil that's slightly acidic (pH 5 – 6.5). They are often referred to as acid loving plants and include azaleas, camellias, rhododendrons and blueberries.
If your soil pH is above 7.5, then you'll need to lower it (make it more acidic). An effective way to lower soil pH is to apply Yates Soil Acidifier Liquid Sulfur, which contains elemental sulfur (S). For best results, apply every 4 weeks until the desired pH is achieved. Take care not to overapply – this won't make the process faster and it can lead to issues with sulfur toxicity, plus cause the pH to drop too low.
There are also some plants that tolerate growing in soil that is alkaline (pH 7.5 – 8.5), including Buddleja, Lavender, Rosemary and Pride of Madeira (Echium candicans).
Healthy soil allows moisture to penetrate down to the root zone where it's needed. Sometimes soil can develop a water-repellent (hydrophobic) layer on the surface; water pools on the surface and isn't absorbed. Water-repellent soil or potting mix can be improved by using a wetting agent like Yates Waterwise Water Storage Crystals.
Most plants do best when the soil is well-drained. Too much moisture can lead to plant roots rotting. Heavy clay soils are more likely to have poor drainage than lighter sandy soils. In addition to adding rich sources of organic matter, like Yates Dynamic Lifter, to the soil, there are additional steps to help improve drainage. Raised beds, filled with free-draining good quality soil, can elevate plant roots above poorly drained soil. Raised mounds of good quality soil can also be created to plant trees and shrubs. More complex solutions include installing drainage channels or trenches, to help move water out of the soil.
Using organic mulch, such as bark chips, sugarcane or pea straw, helps improve the soil. It reduces moisture loss, helps protect the top layer of soil from the elements and as the mulch breaks down, adds organic matter to the soil.
Use organic mulches around vegetable patches, flower beds and trees and shrubs. Reapply mulch as needed to maintain good soil coverage.
Organic gardening is a holistic approach to caring for plants and the backyard ecosystem. A key part of organic gardening is nurturing the soil. Together with making compost and using organic mulches, using Yates Dynamic Lifter Organic Plant Food is an ideal way for organic gardeners to improve the soil.
Yates Dynamic Lifter Organic Plant Food is also rich in organic nutrients, so it's an ideal way to feed plants.