For best results, it should be done in open, unshaded areas.
Solarization in June, July, and August
The best times for solarization are during the summer months of June, July, and August because these have the hottest temperatures.
Remove Weeds and Debris and Till
Clear area of existing weeds and debris. Debris should be removed so it does not poke holes in the plastic. Till site to increase penetration of heat into the top 6 inches of soil.
Moisten if Needed
Water helps to conduct heat, so best results occur if soil is moist but not waterlogged or muddy. On sandy soils in Florida, the best conditions are when the soil received rain or irrigation the day before plastic is applied.
Cover Soil with Clear Plastic
A CLEAR plastic sheet or strip is stretched out over the area to be treated. The plastic piece should be a little larger than the area treated because the edges will need to be buried in soil (see next step). Black plastics or reflective plastics will not allow sunlight through to the soil below. Plastic should be strong enough to last for 6 weeks in the summer sun in Florida without breaking up.
Seal Plastic into Soil
The plastic should be stretched tight and the edges sealed completely by burying in soil. If edges are not completely sealed, heat will leak out and problems may result in these cooler areas.
Solarize for at Least 6 Weeks and Remove Plastic
After 6 weeks, the plastic can be removed, and if the procedure was successful, weeds and soil pests should be reduced for 3-4 months.
Resource: https://edis.ifas.ufl.edu/in856
Plant with Minimal Soil Disturbance
Notes:
- A few small holes may not have much impact on solarization. Use duct tape to seal small holes (< 1” diameter). If the damage is extensive, the plastic may need to be replaced.
- Re-bury or re-seal any exposed edges as soon as possible. Removal of a soil seal or damage to plastic will not ruin the solarization if it is caught quickly and repaired soon after it happens, preferably on the same day that the damage occurs.
- Solarization will kill beneficial soil organisms. The temperatures that are lethal to pest organisms will kill beneficial organisms as well. Fortunately, beneficial bacteria and fungi seem to recolonize solarized soil quickly, so they can still break down organic materials and recycle nutrients if organic fertilizers are used.
- With solarization, the beneficial effects typically last for 3-4 months. After that time, pests surviving deep in the soil can move or work their way upward, or tiny weed seeds might be blown onto the solarized soil.
- Soil solarization is a convenient non-chemical method for managing a number of soil problems including weeds, plant-parasitic nematodes, and soil-borne plant diseases. The main risk to solarization is an extended period of cloudy weather. Solarization cannot be guaranteed to always work because it depends on weather and sunlight, but results are improving as experience increases.
