Hot Sun Photo Courtesy of Lima Andruška

Summer will arrive soon, and with it comes the ferocious heat and disgustingly sloppy humidity we Central Texans have all come to know and loathe.

In case you’re new here, get used to moisture saturated air clinging to your person the way lightweight polyester shorts cling to your damp skin. You know how they slowly insinuate themselves into places you can’t see without a mirror? Summer in Central Texas is just like that.

Eventually you become indistinguishable from a pile of wet, rumpled towels.

While you still have a little strength and dignity left, use the sun and humidity to take out your frustrations on weedy, pest-infested areas of your yard and garden by solarizing the soil.

Solarizing is a method by which the power of the sun works in tandem with moisture to purify the soil. This pasteurization process extinguishes pernicious parasites and pathogens that managed to take up residence in the soil while your attention was focused elsewhere (perhaps that time you were playing tug-o-war with your shorts).

Solarizing the soil is a simple, inexpensive process. A word of caution, though: it does take a good bit of manual labor to achieve the desired results, and so take your time. Nobody’s going to judge you if you allow yourself several days to complete the initial steps of the project. In the end, we want you planting daisies, not pushing them up.

Get started by collecting the items you’ll need to perform the task:

• Round up enough thick, clear plastic sheeting to extend twelve inches beyond your garden’s borders.
• You’ll need a shovel or a spade fork, or a small garden tiller.
• Make sure you have a ready water source nearby.
• Recruit a helper–promise them fresh tomatoes.

If the area intended for solarizing is large, it’s perfectly acceptable to solarize in sections.

The Process

1. Transfer plants in your work area – that are “keepers” – into containers until they can be reintroduced into the newly pasteurized garden bed. If any of these plants are diseased, and you don’t have the heart to dispatch them to the trash, then quarantine them until you can diagnose their condition and nurse them back to health. If they are beyond recovery, they must go to the big compost pile in the sky, not the one in your backyard. If you don’t get diseased materials as far away from your garden as possible, you could undo all the good work the solarizing achieved.
2. Now you’re ready to turn the soil. This process exposes weed seeds and other soil borne troublemakers. Dig three to six inches, breaking up big dirt clods and removing other miscellaneous debris. Dig a large trench around the area you are treating, and reserve the soil, as you will need it later.
3. After you’ve thoroughly tilled the soil, and your trench is dug, saturate the area with good old H2O. Water conducts heat, so the deeper it goes into the soil, the more thorough the solarization process becomes. The “just add water” part of the solarization equation is a two-day procedure, because after you’ve soaked the soil, you go on about your business until the next day, at which time you drench it again.
4. Once you’ve thoroughly inundated the work area with water, pull the clear plastic sheeting over it. If you need more than one sheet to cover the tilled area, be sure to overlap the pieces no less than 12-inches. A helper comes is handy during this part of the project. Push the ends of the plastic into the trenches you dug, and then backfill the soil over it. I generally don’t recommend compressing soil, but in this case, pat down the soil in the trenches to create a good seal around the perimeter. This will help you to avoid losing any of the heat and moisture that builds up under the plastic.
5. Now that you have the garden tilled, watered and covered, and the borders are secured, you’re done for a minimum of two weeks. How long you leave the plastic in place depends on the severity of the pests and pathogens when you started. Two weeks in the Texas summer sun is usually enough time to do some good, but longer is better. Four weeks will give you excellent control of the problem. You can go for six weeks, but if by the fourth week whatever’s under the plastic isn’t dead – it’s un-dead.
6. A few days after you secure the plastic over the garden, you will probably witness weeds popping up. They’ll grow fast and tall and then keel over. The top six inches of soil can heat up to as high as one hundred twenty five degrees, and they can’t take it. Now, don’t worry about our pals the earthworms. Nature provided them with a survival instinct. They’ll come back when that patch of earth becomes a more hospitable place for living things.
7. Once you feel the sun’s done what it was supposed to do during this exercise, remove the plastic and save it for another time. Then lightly till the soil again and work a two to three inch layer of compost into it, to a depth of about three to six inches. Allow the soil to rest for a week before planting it. Just give it a little time to recuperate from the ordeal, and for the microbes in the compost to set up house. Those little things will multiply quickly and create a nourishing environment for the plants you put into the garden.

By marrying the power of the relentless summer sun with high levels of moisture to do the hard work of pasteurizing your garden soil, you’ll have more time for those important things, like wrestling with your Bermudas.