Early last June, the school garden was neglected for a few weeks while students completed the school year. It was soon choked with weeds. We knew we couldn’t leave it all summer without taking care of the problem, so we decided to solarize the garden. I bought large sheets of clear plastic from Home Depot and packages of the anchors that are normally used to hold down black weed mat fabric. Then I asked for help. Mr. Maciejewski, one of the parents in the school, has a landscape maintenance service. He removed the weeds, then covered the soil with the plastic and anchored the edges. Mrs. Bujak-Dominiak and I would like to thank him for his efforts on our behalf.
It is best to solarize for at least 6 weeks. Our garden was covered from mid-June to early September, so we had a few extra weeks of solarization benefits. The photo shows the garden in late August. Some of the summer storms had pulled the edges loose in spots, and a few weeds has grown in the space under the plastic in those areas, but most of the garden was clear of weeds.
Solarizing is based on the green house effect. As sunlight passes through the clear plastic, the heat from the sun is trapped under the plastic. If the soil is moist before it is covered by the clear plastic, the warmed water vapor helps to hold in the heat and makes the process more efficient. The heat prevents seeds from germinating and kills off harmful organisms such as nematodes and soil insects. As you can see from the photo, very few weeds grew during our long-hot Florida summer, so hopefully the nematodes and harmful insects are under control too.
We realized at the end of the last school year that the soil in the garden needed improvement. Our summer attempt to solarize the soil seems to have helped. Although a few weeds grew around the plastic, and some grew where the plastic has ripped, most of the weeds under the plastic were dead by the beginning of August. We can see that the addition of the compost and the solarization seem to have improved the quality of the soil, so we are hopeful for this year’s crop of vegetables.
Last June after the close of the school year, we decided to solarize the garden for the summer. We removed weeds, then borrowed a rototiller to loosen the soil. Next we added several bags of compost from a nearby farm. The final steps were to wet the soil, and then to cover the soil with a clear plastic. The purpose of the plastic was to solarize the soil:
Soil solarization is a practice used to manage weeds, nematodes, diseases, and insects in soil. The soil surface is covered with clear plastic, which allows sunlight to pass through and heat up the soil to temperatures that are lethal to many of these pests. If effective, solarization can reduce population levels of these pests for 3-4 months, sometimes longer.(Read Introduction to solarization on ifas website)
We weighted the edges of the clear plastic with soil, boards and cement blocks to seal the edges as best as possible to retain the heat under the plastic. In the first photo, the lower layer is solarized with the plastic, but the upper layer of the garden is still a mass of weeds. The second photo shows both layers of the garden covered with the plastic. Then we left it to the Florida summer heat to do the work.