Putting Air in the Root Zone

Generally, when we think of a plant's needs, we think of sun, water and nutrients in the soil. Now, pause for a moment, take a deep breath and then let the air out. That is respiration. What many gardeners tend to forget - or maybe don't know - is the plant's overwhelming need for air in the soil.

Plant roots must breathe (respire) the same as the foliage. If not they will suffocate: either partially, allowing only slow growth, or they will just plain die. This can occur over a few short weeks, or gradually over several years.

When I plant, I aim for a 50/50 mix: 50 percent solid particles and 50 percent open spaces in the soil. In these open spaces we provide the possibility for a mix of air and water.

Before you plant you need to create this airspace-especially in Ohio's heavy clay soils. If you do create and maintain air spaces for the roots, you will have a happy root system and hence, a happy plant. Nothing happens above ground until the root system is in good condition.

There are several steps to take to ensure this during preparation for planting. You should realize that whether you are preparing an entire garden or just an individual planting pocket for a tree or shrub, the process is about the same.

First, wait until the soil is fairly dry; wet soil can't be prepared properly and you increase your potential problems by working under too wet conditions.

Remove the sod one to one and a half inches deep, and stack upside down (so it will die) near the edge of your compost pile. Once dead, this can become compost for another year's use.

Now, add to the surface of this cleared area three to four inches of compost and/or peat, and or composted manures. Use the results of your soil test to add the nutrients recommended or to adjust the soil pH. Blend these together-for a garden, to a depth of 12 inches; for a tree or shrub, as deep as the ball itself.

When you blend these materials, the goal is to break up the hard soil and incorporate the additives, creating a better root zone. The most important thing is to know when to stop. When working with a shovel, your back may tell you when you've gone far enough, but when a roto-tiller is being used., the tendency is to go too far and pulverize the soil. You are looking for a variety of particle sizes in the soil - from the size of a pea to about the size of a golf ball. Rememer, we're working to create air spaces between the soil particles.

To improve the site of already-established plants, work slowly and only at the surface. You can scratch slightly, (only one half to one inch deep, to avoid disturbing the established surface roots) and add small amounts of peat and compost that naturally but slowly will work their way down to the roots. However, the next most beneficial thing you can do is properly fertilize and mulch these plants and let Mother Nature take over from there. If your soil is rock hard, aeration may be necessary but I would consult a professional before taking any drastic steps.

So before planting, prepare your soil well and get the plant off to a proper start. Place the plant on a slightly raised mound in the hole, and when you put the soil around the plant do not pound it down. Lightly tamp the soil in place after the hole is filled, and don't forget to leaev a slight reservoir all around your new plant. Water thoroughly, letting the excess drain away so the roots can breathe, and watch it thrive.