Six-foot-wide clear film applied to single beds

Wet soil conducts heat better than dry soil, making soil organisms more vulnerable. Before laying plastic film, thoroughly soak the beds by using the drip system in combination with a surface watering. Most beds will not need to be irrigated again during solarization. However, if the soil is sandy or if the beds have a high profile, it may be necessary to re-irrigate using the drip system.

Plastic solarization film can be applied to beds separately or in combination. When applied to single beds, the film is laid like mulch film. See Plastic Mulch Application section for details. In complete coverage, film is laid down to form a continuous surface over a few beds or the entire garden, depending on the size of the sheet. The edges of the film should be held in place by burying them in the soil.

For small gardens, UV-inhibiting clear plastic film, sometimes called drop cloths, can be purchased from hardware or home improvement stores. The plastic film can be cut to size or spliced with clear patching tape. The heavier, thicker film is more tear- and puncture-resistant and can be reused.

For market gardens, clear film can be purchased in rolls 6 feet wide by 2,000 feet long or longer. The 6-foot width is ideal for 40-inch-wide beds. For a list of companies that carry large rolls of clear film, see the appendix.

In southern states, film should be left in place for four to six weeks to allow the soil to heat to the greatest depth possible, while in cooler climates, film should remain in place all summer. Results are best with high solar radiation and minimal wind, regardless of geographical location.