From Sarah's garden to yours
Most gardeners are stirred into action by the first warm day. They head off to the garden centre, grab everything they want to grow, hastily clear the beds of any weeds, throw in all the plants and hope for the best.
The essence of a successful garden is good soil
One of the key factors linked to a successful growing season and a bountiful harvest is having the best soil possible. Not all soil is created equally though so what may be right for your neighbour may not be right for you. There exists no set formula for making good soil as it is all different. You first need to understand your soil and work out what it needs to be at its best and then do what it takes to make it so.
The expression ‘you are what you eat’ applies to your harvest too. If you have poor soil, then the quality of your food will be poor, and the reverse is equally true. If you have nutrient rich soil then your food will be nutrient rich. That being said it is in your best interest to really understand what is going on in the ground you will be growing your food in.
What is soil?
It covers all the dry bits of the earth, and considering its importance, we surprisingly walk all over it without giving it a second thought every day. As far as gardeners are concerned, there are four layers of interest.
Mulch
This consists of all the organic matter lying on top such as lawn clippings and fallen leaves. Gardeners can recreate this natural layer by adding it to their veggie gardens to retain moisture and suppress weeds.
Topsoil
This is the layer that plants grow in – the place where roots call home. There is a lot of activity taking place in this layer. Earthworms live here and work hard to process organic matter, especially bringing down goodness from the mulch layer and aerating the soil by creating tunnels all through it. Microorganisms such as bacteria and fungi break down organic material and convert nutrients into plant-friendly food. Fungi also help the roots do their job of absorbing nutrients more efficiently.
This layer is also made up of inorganic matter - minerals and fine particles of rock based beneath it. The organic and inorganic matter work together to give the soil structure, drainage and the all-important nutrients.
Subsoil
This is the next layer down and is of a more inorganic nature, having more in common with its rock origins. It isn’t really a layer you want to incorporate into your growing zone. The main contribution it offers to your garden is drainage. A clay subsoil can result in a boggy topsoil, and a sandy subsoil in a dry garden that holds very little water.
Water Table
This is the last layer that has any significant impact on your garden. It is the level below the surface where the water in the soil normally sits. It will increase with rain and decrease in times of drought, but generally it has a level where it normally sits during each season. This will impact your drainage and irrigation needs.
Now that you have a better understanding of the composition of your soil, it is important to understand other important factors to ascertain its quality.
Texture
The inorganic content of your soil is generally made of a mix of three elements Sand, Silt and Clay. The ideal soil is roughly 40% sand, 40% silt and 20% Clay (+/- 10%). If a layer is larger than that, it will be harder for the plants to thrive and will need to be adjusted.
If you have a high clay soil, it can be improved by adding loads of organic material, compost, manure, and a little pumice or grit to help with drainage. Also, a little lime to help break up the clay.
If you have a high sand content, adding loads of organic material such as compost and manures from vegetarian animals will greatly assist with the water retention of sandy soils. You can add some bought topsoil that leans towards more clay or silt to redress the balance. Also, feed the garden often with fertilizers during the season as nutrients are easily lost.
Loam soil is really the best kind of soil, but you have to work with what you have – or build a raised bed and fill it with a lovely loam soil.
Earthworms
These little guys are great friends in the garden and they love a healthy soil. So to check your soil quality, conduct an earthworm census. Dig a hole 20cm square and about 20cm deep and take the soil from your hole and go through it looking for worms, count them as you go. If there are more than 10 worms then you have great soil. Less than five worms, you need to add a large amount of organic matter. If there are no worms then your soil is in such a dreadful state that even worms won’t live there.
pH
If you remember high school science class, the pH scale goes from 0 – 14 with 0 being very dangerously acidic and 14 being corrosively alkaline; 7 in the middle is neutral like tap water. Most veggies like to grow in soil that is between 6.0 and 7.5. There are exceptions to the rule, so it is best to research what your plants actually prefer. If the soil is too acidic, it can make the nutrients too soluble and they will float away. If the soil is too alkaline, the nutrients can be held up tightly by the soil and the plants can’t get at them.
You can reduce the acidity in your soil by adding a little lime; also known as sweetening the soil. Don’t overdo it though – less is more. Increasing the alkaline level in soil can be done by adding sulphur – often sold as flowers of sulphur. Follow the instructions on the packet carefully.
Remember that with the harvesting of crops and removal of plants at the end of the season, you are constantly depleting your soil of goodness. This goodness needs to constantly be added back in to keep the soil healthy. If you just grow and take and give nothing back, within a couple of years, your soil will be useless for growing plants.
