Loosen soil to allow roots to roam
Posted: Tuesday, March 10, 2009 8:01 pm
By JIMMY WILLIAMS
Special to The Messenger
You know, of course, the great principle of success with growing any plant. Any plant.
It consists of three parts: soil preparation, soil preparation and soil preparation. Without proper soil preparation, you’re wasting your time, whether your goal is a healthy geranium for the window sill or 1,000 acres of high-yielding corn.
Without proper soil preparation, even one cornstalk won’t yield any ears. More to our present point, with any ornamental you plant, from a lowly marigold to a rare Japanese maple that could set you back beaucoup yen, failure is guaranteed without the right soil conditions.
Soil in this neck of the woods is almost universally clay-based. There are a few exceptions, but most woody plants and perennials will not stand wet clay around their roots during the winter. In normal winters, few plants rated hardy here will die from freezing, but plenty of them succumb to wet feet.
The trick is to break up that clay and convert it into a more porous medium. The best amendment for that is filter media, a product of our gravel mining operations east of Paris. Filter media is crushed gravel that has been through several washings until there is no dirt remaining. It is pure sharp gravel, less than one-fourth inch in size.
Added liberally (it is hard to get too much) to clay soil and deeply dug or tilled in, the results can be astounding. Formerly barren plots, amended with filter media and some nourishment (more of which anon), suddenly turn into a productive growing environment.
On one of our British garden tours years ago, the value of grit such as this added to the soil was brought home when I purchased several potted nursery plants. Our instructions were to thoroughly wash all soil from their roots in order to pass agricultural customs when we entered the U.S.
When I did that in our hotel sink I found the potting medium to consist of at least one-half grit, the rest being good loam. Roots on the plants were vigorous and reached to the bottom of the pots. It was a dramatic picture of what can happen when plant roots have an airy mixture in which to roam.
After returning home, I tried to find a product that approached the grit we found in England. The nearest thing I could buy was bagged chicken grit, too costly to use on any sizable scale. Then I turned to concrete (not mortar) sand. It turned out to be very useful, but didn’t provide as open a medium as larger bits of gravel would have.
Then came discovery of filter media. A friend at Tennessee Asphalt Co. brought it to my attention, and since then I have used upwards of 10 tons of it on all my beds and borders and in planting holes for perennials and woody plants.
Filter media is used in water filters in municipal water and wastewater systems. It is sold on a large scale by the ton and shipped from here all over the southeast.
Commercially available at garden centers and nurseries are bark chips. These are used as amendment in heavy soil as well and, in fact, wholesale growers use them as amendment to loosen soil for potting up perennials and woodies. This is fine and dandy as long as automatic watering is available. Water drains through the chips almost immediately, but when fertilizer is added automatically, as it is with most big growers, plants grow like a house afire in the stuff.
The downside of bark chips, as compared to filter media or coarse sand, is the fact it will rot away before too long, leaving clay soil right back where it started. The filter media or sand is permanent and will be around a lot longer than any of us. Any soil amended with either will stay amended.
Gravel or sand has no food value. Nourishment must be added to soil when they are used. This can be in the form of artificial fertilizer or, better, with organics such as manure and humus. The ideal time to add this is when amending with the gravel or sand. A mixture of one third gravel, one third humus and one third soil is about right.
A new bed can have the amendments simply spread on the ground, then tilled in with a rotary tiller or, on a smaller scale, dug in with a spade or fork.
From Poor Willie’s Almanack — Use filter media so roots can roam throughout your loam.
Editor’s note: Jimmy Williams is production superintendent at The Paris Post-Intelligencer, where he also writes this column.
Published in The Messenger 3.10.09