David Robson Extension Educator, Springfield Extension Center, University of Illinois
Yard & Garden
Working the ground
Help Mother Nature along with soil enrichment
Spring will arrive sometime this month with any luck. Experience tells us it will. We can only hope.
And with spring comes thoughts of getting into the garden as soon as possible for those with true green thumbs. For others, procrastination is the first order.
It all comes down to the soil. If it’s dry and the temperatures are right, we can plant. If either condition isn’t acceptable, planting is a waste of time and money. Plants and/or seeds can just sit there rotting or becoming worm and bird fodder.
The ideal soil will allow you to plant early. It warms up faster and drains quickly enough that you can till it without worrying about destroying the structure.
Does anyone have the ideal soil? Few.
Woodland soil isn’t ideal. Old prairie grass soils are probably the closest to the ideal. Old, in this case, is thousands of years.
If you live in a home that’s been built in the last 50 years, your soil is also far from ideal. Even the shallow organic woodland soil is better than an urban soil.
Two important aspects about soil are organic matter and texture.
Texture refers to how much clay, silt and sand is in the soil. Sand gives the soil its gritty feeling, while clay is smooth. Sandy soils warm up fast and drain fast. They are the ideal spring soil, though they have an abundance of large pores, which makes them harder to stay moist.
Clay on the other hand holds more water than a sponge. It’s hard for warmth to penetrate; rotting is a constant battle.
Yet, you need both clay and sand, coupled with silt, to make a great soil. Sadly, though, you just can’t add one to the other and call it done.
Most gardeners wouldn’t think about adding clay to a sandy soil. Instead, they just water more often and add organic matter.
On the other hand, those with clay soil think you can just dump a little sand in the clay and it’s magically better. However, and this is a super-big however, you need to add 8 parts of sand for every part of clay. In other words, you need to mix in 8 inches of sand for each inch of clay, or 8 feet of sand for a foot of clay.
The reason is that clay will fill in between the sand particles and you end up with something close to concrete.
That’s where organic matter comes in. Organic matter is the tie that binds particles together. Add some to clay soil and it forces the clay particles a part. Added to sand, it fills in without causing a concrete-like hardness. And you don’t have to go with an 8 to 1 ratio. Generally, 4 to 6 inches of organic matter tilled in is enough. Compost and composted manures are the best sources.
However, (and I emphasize this), organic matter doesn’t last forever and ever like sand and clay. It will break down over time and you’re left with your sand and clay again.
Breakdown speed depends on the initial quality of the soil and weather conditions. Generally though, most organic matter is broken down within a year. You might be able to find about a quarter-inch of your organic matter a year later. That’s why you sometimes need to lift up the perennials you planted every three to five years and add more organic matter.
You could start by adding more organic matter in the first place, but realize it’s not always the best growing media and it can be difficult to till in, though if you are intent on doubling the organic matter, do so in smaller amounts, making several tilling passes over an area while adding the material.
David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, University of Illinois Extension, P.O. Box 8199, Springfield, IL 62791. Telephone: 217-782-6515.
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