In this week's blog, we reinforce Carolyn's efforts to create the perfect soil in her new garden.
The old saying "You are what you eat" applies to eating nutritious food to stay healthy, strong and able to fight off germs and this can be applied to your soil too. Just as we need good nutrition, so does your soil. It doesn't like being taken for granted with assumptions being made that it's all about the plants. If you look after your soil, your plants will look after themselves. They'll be strong and healthy, productive and disease resistant.
What do you do to prepare your soil for your spring crops? As we head into winter, it's a great time to address the health of your soil.
WHAT IS HUMUS?
Humus is used to change your sterile dirt into fertile soil and is derived from all sorts of organic matter. Its presence brings your soil back to life, creating a loose structure that simultaneously holds moisture and drains well. It creates an environment which supports living organisms that convert soil nutrients into a form that plant roots can use.
IS THERE A DIFFERENCE BETWEEN HUMUS & COMPOST?
On reading quite a few opinions on the web there is a common reference to humus being the carbon material
(dried materials such as prunings, leaves, sawdust) and compost being the nitrogen material (moist materials such as vegetable peelings, grass).
The main purpose of humus is to create a crumbly, loose and aerated topsoil. This allows life within the soil to do its magic. The carbon matter that makes up humus is the dried brown material and may include one or more of the following;
- leaves & leaf mould
- untreated sawdust
- animal manures
- mushroom soil
The nitrogen matter is the more moist matter and may include all of the following;
- grass clippings
- vegetable scraps
- fresh weeds
Mix the two together and leave to reduce. The air and moisture will generate heat as the materials break down. Tiny organisms, fungi and bacteria which live on the surface of your materials will act as a very functional and efficient food chain which will eventually reduce all the matter to a soft dark humus. To encourage this process to happen faster, create more air by turning or stirring the pile more often or add worms.
There are many:
- dense sticky clay
- thin gritty sand
- powdery silt
- loose loam
There is no such thing as a perfect soil as every soil has problems in structure, texture and/or chemistry. The best way to understand your soil is to use a testing kit from your local garden centre or hardware store. Alternatively, most garden centres can test a soil sample for you for a small cost.
The amount of humus you need to create healthy soil depends on which soil type you have. The main aim is to create lots of air space in your soil.
WHAT PROBLEMS CAN HUMUS FIX?
Typically, soil in a home garden is compacted, the air compressed from it by the weight of foot traffic, construction, mechanical equipment and harsh weather. To reduce compaction, regularly add humus in the form of a topdressing to existing lawns. Spread mulch of organic material on bare soil in garden beds when planting to improve aeration.
Sandy soil has large particles with large air spaces between them, therefore it drains quickly leaving your soil too dry to support most plants. This also means water-soluble nutrients leach out rapidly before the plants can use them. Adding humus will create more of a sponge-like environment, holding moisture and nutrients dissolved in it. Replenish the humus content of sandy soil at every opportunity.
The small particles in clay result in small air spaces between them. The particles then stick together and cause water to fill up the air spaces and since moisture cannot drain away, plant roots tend to rot. Adding humus prevents the small particles from sticking so tightly, creating larger clumps, creating larger spaces that drain more easily and hold air for improved soil.
Fluctuating pH levels
Humus buffers soil against changes in pH so adding lots of organic matter will help maintain desirable pH levels. The acidity or alkalinity of soil affects how nutrients are taken up by your plants. Reduced acidity (pH higher that 8.0) inhibits the uptake of iron, boron, copper and other elements. Excessive acidity (pH lower than 6.0) discourages plant absorption of other nutrients. The pH levels in your soil can be measured with your soil testing kit. Add sulphur to increase acidity or lime at recommended rates to reduce acidity.
Pest insects, disease pathogens in soil
Humus in your soil creates an organically live environment. It supports micro-organisms to process nutrients and harbours beneficial macro-organisms such as ants and ground spiders that prey on soil dwelling pest larvae and eggs. It also supports beneficial nematodes and also bacteria such as milky spore that combat white grubs in lawns. Of course, the "numero uno" indicator of a healthy soil is worms and lots of them. They aerate the soil, break down plant matter and add vermicast and beneficial fungi.
Soil becomes sterile over time as its humus content is reduced by hot weather, removal of topsoil or intense cultivation without replacement of organic matter. The number and activity of micro-organisms in the soil is depleted and in their absence, the production of nutrients to plants is severely curtailed creating a sterile environment. Fertilizer does provide nutrients to the plants but is not able to solve a soil fertility problem. Supporting resident micro-life in the soil is the long-term solution.
The benefits of treating your soil to a good feed are many so why wouldn't you do it. You can then look forward to the marvellous harvest that your nurtured soil will provide in spring from just a bit of effort through the autumn and winter. So how's your soil looking? In need of some TLC? Perfect timing for creating your piece of Good Earth......