Soil Preparation & Drainage

The first place to start with almost anything in your garden is the foundation ‘the soil’. Why? Because the soil is your ecosystem and its health will determine your tree or plant’s success or failure. So, let’s take a look at the important topic of soil preparation and drainage.

Start by developing a good understanding of the soil type you are dealing with. The most basic three soil types are clay, loam or sand, but there are also many varied blends of these soil types.

Soil Types

Clay soils usually contain an abundant supply of microbial life and nutrition for your plants. However, its ability to hold water excessively can result in a poor lawn drainage or a garden area that is set back from the effects of water-logging. Often plants will turn yellow or leaf drop when the oxygen disappears from the soil and it begins to sour and become anaerobic. When plants don’t do well in clay soil, the answer is nearly always drainage. Good drainage is achieved by blending gypsum or course sand with the clay to allow water to pass through it. Alternatively, you can install a drainage system to allow water to freely drain from the area. If you are planting trees on a bank, the digging of a French drain from below the hole you have prepared for your tree is a good idea. Large gravel and perforated AG drain is useful for this purpose. This will prevent the young roots being burnt off from water logging and in turn help them to develop and grow.

Sandy soils are at the other end of the spectrum and usually contain less soil life, as they hold less moisture, tend to be free draining and become dryer faster. For these reasons, sandy soils in a garden bed will benefit from humus (i.e. compost, mulch, animal manures), as they retain moisture and nutrient at the top of the soil layer, keeping microbes cooler and protecting and nurturing the many organisms beneficial to plant health and growth.

This is different when growing turf in sandy soil, as the best soil type for growing turf is large particle sand. Why? Because you are now trying to promote free draining soil, and cause the roots system to grow deep. This is achieved by using watering patterns that allow the soil to dry out thereby encouraging the root system to grow deeper. A large particle sand should have less fine sand and will be less likely to cause a clogging affect beneath the soil.

Loam or Sandy Loam soils are the happy medium and are usually best suited to most growing conditions. You will hear of the terms 80:20 or 60:40 used in landscape supply yards. This is a reference to the sand soil ratio. The higher number being the sand content.

Soil Preparation

So, why would soil preparation play such an important role in the success of the plants and life in your garden? Let’s investigate this question a little further.

Firstly, the soil or biosphere as it is scientifically referred to, is a living thing that is an ecosystem with biodiversity like we see above ground in the plant and animal kingdom.

Each of these living organisms play a part in the health of your soil and improve nutrient uptake and health, by converting nitrogen and improving the availability of many elements and nutrients in the soil to plants, and decontaminating soil by eliminating harmful pathogens and fungi that threaten the healthy balance of your soil.

We must understand how this ecosystem can be allowed to flourish or be detrimentally affected in order that we see how we can bring better understanding and thereby improve our growing techniques.

Okay, so we have purchased our new soil and placed it into our garden. What do we need to do now to kick start the soil into life?

Start by adding some of your native soil to it, and introduce some of the indigenous microbe population to your new soil, then feed the soil with liquid Humate. This will increase your microbe population faster and support increased life in your soil. Next dig in some compost, turn it into the soil and mulch the top with some pea straw or other type of organic cover. The next ingredient is one of the major keys in successful gardening: TIME. Yes, give it some time to break down and convert those wonderful soil amendments into a living pool of vitality ready to nurture and support your valuable plantings.

PH is another important indicator of soil suitability, as most plants have an ideal PH range they like to grow in. When the PH range of the soil is not suitable for the plant, it will find nutrient uptake difficult and deficiencies may occur causing yellowing of the plant or poor leaf colour. It is therefore a very good idea to check and adjust PH when it is unsuitable for the plant and wait a while before planting.

This is extremely important when planting acid-loving plants such as Camellias, Azalais Blueberries or Cranberries. We must understand when adding sulphur to soil to cause a soil to become acidic you don’t need a lot of sulphur, and it is the reaction in the soil with the sulphur that causes the acidity—another reason to delay planting until the process has run its course.

Fertilising plants should always be relative to the plants needs and follow the “little often” principle rather than starving them to death then burning them off with too much. We often see plant fertiliser through the eyes that we view our own food that we eat to sustain our bodies, and forget there is much food in the ground already, if your soil is healthy. For instance, citrus trees and roses burn a lot of elements when producing flowers and require more regular feeding. However, when growing tomatoes, a pinch of Potash will last the whole growing season, and the soil amendment we dug in pre-plant will see the crop to maturity.

Care should be taken when planting new trees or small plants. Acidic based fertiliser can burn new roots and should be avoided. Seasol and other plant humectants, pre-plant and post planting will support plants through the transplantation stage and small amounts of Blood & Bone or Seamungus in the hole will help stimulate new root development beyond the planting area. Compost mixed with the back-filled soil will also stimulate the soil life and support strong healthy new root system.

So, successful planting and growing is not about good luck, or having the green thumb, it is about understanding, timing and preparation and that all important ingredient: time.

And don’t worry about the failures, they are just fertiliser for tomorrow’s success.

I hope this inspires you to get gardening!