Today’s post is focused on Soil Science

Soil science: Know it and succeed in your garden.

Today’s blog is a basic rundown on some soil science which may help you succeed in your garden. If you have experienced a lot of fatalities in your garden, despite the fact that you feel that you are ticking the normal garden health boxes it could be an indication that you are planting the wrong plants for your type of garden soil. The other way to deal with planting your wish list is to try and alter and improve your existing soil, even though this does take years and much effort. Your garden can interestingly enough contain different kinds of soils.

The first thing you need to do is identify the type of soil that you have. Soil is classified according to the size of its particles. Sand has the largest particles, clay the finest and silt falls somewhere in between these two types. Loam is a combination of sand, silt, clay & organic matter and is what is nicknamed generally ‘the perfect soil’.

Clay soil:

This is very heavy soil which is a tan to dark colour usually, with a smooth feel as it consists of fine particles between which are very small particles. This soil is the most difficult to work with as it is very sticky when wet and hard when dry. This kind of soil holds a lot of water (high water holding capacity) and lacks air around the roots. This can all lead to plants rotting and fatalities. This soil is because of this, cold and is slow to warm up in spring which can slow a plants growth process. The pro to this soil is that it is rich in nutrients and retains these nutrients.

There are some ways to improve this kind of soil. Clay can be improved by digging in organic soil amendments at every opportunity. Soil amendments include compost, humus, well-rotted manure and leaf mould. This will loosen up the soil, aiding aeration and drainage. Dig about 8-15cm of compost when preparing for new beds or lawns. A top dressing of agricultural lime or gypsum helps to separate the particles. A good thing to remember is to not dig or walk on wet clay as you will further compact it, and press all the air out of the soil.

Sandy soil:

Sandy soils are usually light in colour, feel gritty and rough to the touch and don’t hold their shape. Water runs straight through, they contain little organic matter and seriously lack nutrition. The pros of this kind of soil are that they are easy to cultivate and warm up quickly in spring meaning plants have a quicker growth spurt. Roots also grow better and with greater ease as it isn’t as dense, again leading to quicker growth.

There are again some ways to improve this kind of soil. Dig in as much organic matter as possible, like compost and manure. This will improve the soils texture, water holding capacity and ability to retain moisture. Sandy soils should be dealt with a little differently to other soils. They need to be fertilised more regularly as they don’t retain nutrients. Also they should be given smaller amounts of water but more frequently, as sandy soil is not good at retaining water. If you have what is called hydrophobic sand which repels water, then you should keep it well mulched.

Loam soil:

Loam soil is dark in colour and consists of a good balance of sand, clay and silt as well as lots of humus and organic matter. This mixture leads to there being a balance of large and small particles, with mixed pore sizes. This is the best kind of soil type and is crumbly, highly fertile, well aerated, and high in nutrients and holds them well and although it drains freely, it still retains moisture. Though this is a fantastic soil it still requires composting, mulching and shouldn’t be over cultivated.

There are a couple of different ways to check the texture of your soil and therefore judge what type of soil you have. Just remember there can be great variation between different areas of your garden. There are two more simple tests and then one which is more complicated but more accurate.

The sausage test:

Wet an area of soil and collect a handful. Roll this into a sausage shape and gently bend. If it very crumbly and breaks before you can bend it then it is sand. If it holds its shape and then breaks slightly when bending then it is loam. If it bends and totally holds its shape then it is clay.

The ball test:

Wet an area of soil and collect a handful. Roll it into a ball. If the soil will not bind together then the soil is sandy. If the soil moulds into a loose ball but breaks quite easily then it is loam. If the ball completely retains its shape then the soil is clay.

The Mason jar test:

This is the most precise way to figure out what type of soil you have, and will tell you exactly what your sand, clay and silt ratio is as well as giving you and indication whether or not your soil contains organic matter. Collect three samples from different parts of your garden at soil level. Spread the soil out in the sun and break up any large clumps that are present. When they are dry pour the samples into three separate straight sided glass jars with screw top lids. Add a teaspoon of dishwashing liquid, fill the jars with water and screw the caps on. Shake the samples for three minutes making sure no soil is stuck to the sides and then set samples aside. The sand content will settle very quickly. The silt component will settle within a couple of hours and the clay will settle within a day or two. There will be three distinct layers as well as hopefully organic matter floating in the water. These layers now need to be measured. This needs to be done by first measuring the combined layers. This represents 100% in the bottle. Then measure each layer separately. Divide each layer’s thickness by the overall total. Then multiply the answers by 100 to get the percentages. Once you have the percentages insert them into the soil analysis triangle below. Draw lines parallel to the lines existing on the triangle. Where the three lines meet will determine what kind of soil you have.

Sometimes it is easier to plant according to your soil type rather than amending your soil as this can take many years. Below is list of plants for the soil types discussed.

Clay soils – Canna’s, Daylilies, Acacia trees, Rose (Need to add organic matter and mustn’t be too waterlogged), ornamental grasses (Carex), thatching reeds, Irises etc. (Plants which can tolerate waterlogged soils)

Sandy soils – Succulents, Aloes, Cacti’s, Mediterranean plants (Rosemary, Lavender etc), grey leaved plants (Rhagoda histata/salt bush) and in general indigenous plants etc. (Plants which can tolerate very well-drained, nutrient deficient conditions)

Loam – Any plants will grow in this soil but succulents, aloes and cacti’s prefer growing in sandy soils.

Now that you know more about soil texture and how to identify which soil you have, it might help you to adjust and improve your soil to what will hopefully eventually be loam, or plant according to your soil type. If you have any queries please let us know and we will be happy to answer your questions to our best capabilities.

We hope the hints and tips in this blog will help you to create your perfectly landscaped garden that you have envisioned.

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