Why is soil so important?
People trying to grow ‘the perfect lawn’ or gardeners may think that weeds are the most troublesome problem. It is probably more accurate to say the number one thing that will disappoint (and dishearten) a home owner or a gardener is working with soil that is unproductive and difficult to manage.
Do you have a prolific crop of weeds each year, while desirable plants struggle? Why does that happen? Many weeds have adapted to grow in poor soil while specialty plants do not adapt so easily. A garden that offers an inferior growing medium will probably have the less desired plants dominating the landscape.
Think about what kind of plants you want to grow. Changes to the soil can make that possible. If you have been disappointed with attempts to grow some of your favorites, the solution may be tied to what is happening below ground. First you will need to determine the characteristics of your soil, and compare that to the requirements of the plants you wish to grow. Some of the changes you can make:
• improve drainage to remove excess water or increase the ability of the soil to hold moisture
• alter the pH of the soil
• increase the amount of organic material
• evaluate nutrients like nitrogen that may be inadequate or excessive
• aerate soil that is compacted
• protect soil from baking in the sun by using mulch
Does this sound like too much work? The alternative to modifying the soil is to restrict yourself to a category of plants that grow in the type of soil and growing conditions you currently have.
Remember, the life of the plant depends on the life of your soil. Working below the surface, hidden from our viewing, are fungi, bacteria, protozoa, plant systems, insects, worms, mammals, and reptiles. All of these live in the soil, affect its structure, and aid in its development.
This life in the soil depends on dead stuff in the soil. Bacteria and fungi are present whenever the soil contains organic matter in the form of decaying plant and animal matter. Soils which have been depleted of organic material, or baked in the sun with no protection, or polluted in some way, may have limited or no microbial action. The bacteria which live in the soil are of great importance in helping to make food available for plant growth. Chemical elements or compounds in the earth must be converted into forms that plants can use. The process of breaking down material to make it available to plants is carried out by bacteria, fungi and other basic life forms.
Soil is made up of these items (not exclusively):
Mineral particles of different sizes and shapes, called sand, silt and clay;
Organic matter in various stages of decomposition; Air and Water. The ideal soil is one that holds moisture and at the same time allows a constant flow of air through the soil. Soil cannot be over-saturated with water or air would be excluded. Air flow brings oxygen to the roots and to micro-organisms, and removes carbon dioxide from the soil.
Note: Sand provides fast drainage and good aeration, but fails to hold water. Clay has great water holding ability, but is dangerously low in supplying air to the soil.
So why does a gardener need to know this technical stuff? To help your roots. The basic functions of roots are: anchor the plant, and provide water and nutrients from the soil as the plant needs them. The ability of the roots to do this depends on certain characteristics of the soil. If you can’t grow healthy roots – you can’t grow healthy plants – if you don’t have healthy plants you don’t have a healthy lawn or garden. The quality of the soil can help or hinder a plant. The circle-of-life is all interconnected and is actually a balancing act.
So how do you improve the quality of your soil? Organic matter. This must first be broken down and digested by soil organisms (bacteria, fungi, small insects, etc). Collectively, they release nutrients in an organic form that plants can use, while also improving soil structure. Organically derived nutrients bind to soil particles and are far less likely to leech. The net result is nutrients that remain in the soil until utilized by plants, with little risk to plants of burning or dehydration, even in periods of extreme drought or over- application.
As we continue to feed the soil with organic matter (through compost, leaf litter, worm castings, food scraps, natural fertilizer, etc.) existing soil organisms utilize these and continue to supply food and nutrients for a soil environment that supports other living organisms and plant life. The result is a thriving, balanced ecosystem.
Whether you buy or make it, compost is the best way to feed the soil. Compost improves soil drainage, yet allows soil to retain sufficient moisture. It helps create the type of soil structure that is critical for nutrients and water to be absorbed, and plant roots to spread. Compost also helps reduce soil erosion and runoff. It protects plants from certain diseases, moderates pH levels, feeds earthworms and other soil-dwelling creatures, supports beneficial microorganisms, is known to be a growth stimulant, and even buffers toxins in the soil. And the best part – you can easily make your own compost for free.
All the ingredients you need come from many things you would otherwise throw away from inside and outside your house. How much to apply? Strive for 5% organic matter by weight in your total area. As a rule, one-inch worked into the top four to eight inches of soil will get you close and provide excellent results for your garden. For lawns, spread a thin layer of compost over the top of existing grass and work it in with the flat side of a rake until it is driven down to the roots.
References: University of Minnesota, University of Nebraska