The need for well-draining soil

 HOW DOES YOUR GARDEN GROW

By Kit Flynn
Columnist

Sometimes, I mention the need for well-draining soil in the garden until I begin to bore myself with my repetition. However, Debby’s recent arrival was a great lesson in demonstrating that certain garden lessons cannot be overemphasized. I know that this topic elicits yawns, but believe me, it’s the basis of a successful garden. Put another way, this is a truism about gardening: Your garden is only as good as your soil.

A dear friend of mine called me after Debby had made her appearance to say that the mulch in her garden was floating – and this is because her clay soil simply could not absorb the deluge quickly enough. Now in the Carolina Piedmont, most of us have clay soil, just as they have sandy soil at the beach.

While many of us complain about our clay soil, it has some positive aspects. For the most part clay soils are relatively nutritious. My friend’s clay soil produces daylily clumps that far surpass mine for example. Clay soil retains water far longer than in the sandy soils where water simply slurps its speedy way through the earth. Obviously, this is a benefit during a drought, such as the one we experienced in June.

There are a couple of drawbacks, however, to clay soils. With its small grains of soil – as opposed to the large grains of sandy soils – a sudden deluge water cannot seep through it quickly. Why is this a detriment? Plant roots require oxygen along with their need for water. Left too long in standing water, roots will begin to drown. It’s painful to see this happen in a garden nurtured over the years. The minute spaces of air found in between the small clay particles fill up with water quickly – and the excess water has no place to go.

Logically, it would seem to make sense to add sand to clay, thereby interspersing large grains of soil with small grains. However, you must never do this, as it will create a cement-like soil that is impossible to work with—and we complain how hard our clay soil is already. The solution to the clay soil problem is to add organic matter to the soil, making it loamier.

What is this organic matter that gardeners prattle on about? It’s basically compost, either your own or purchased. We must add this to clay soils to lighten it up and firm sandy soils up. Another efficient way to add organic matter to our clay soils is to cover it with a good organic mulch that will gradually decay.

Pine bark mulch is readily available and is attractive. I cannot recommend pine needles as a good mulch because they take forever to decompose – and you want your mulch to break down. This gradual deterioration is precisely what you’re aiming for as it is an easy way to increase the organic matter in the soil.

Another good mulch is one you attain every fall – and that is those leaves that fall to the ground beginning in September. Run the lawn mower over the leaves to aid in a quick decomposition. What you don’t want to end up with is a soggy impenetrable mass of leaves that will starve the soil of oxygen and water, so you need to break down most leaves.

Some leaves are simply too large and leathery to turn into a good mulch. Magnolia grandis produces thick leaves that simply smother the soil and the plant roots – and they take years to erode. Some trees, such as the pin oak, produce leaves small enough so they need little manipulation to become a suitable mulch. I used to cover my garden with pine bark mulch every year until I realized that my pin oak did a pretty good job all on its own. One advantage of the pin oak is that it sheds its leaves over several months rather than all at once; this is the equivalent of adding mulch a little at a time.

Now, there are some plants that can tolerate both the wet conditions Debby inflicted upon us and dry periods such as those we experienced in June. For a list of plants suitable for rain gardens, press here. Several good instructional videos explain how to set one up.

Another alternative is to employ the raised box method of gardening, also explained by numerous videos. Many gardeners use this method for raising vegetables – and they can be quite attractive. Again, there is a lot of good information available online here.

There are places, such as in Iowa, where Nature has given us the perfect soil. However, in most of the US – at least in the eastern half – we have reason to complain about our soil. Here’s the thing however: You can adjust the quality of your soil, but this takes time and it cannot happen overnight. Gradually you will see an improvement and during another Debby-like storm, your mulch will remain in place.

This reporter can be reached at Info@TheLocalReporter.press