How long does it take to solarize soil?

Question: How long does it take to solarize soil? I am interested in trying it out, but I don’t necessarily want to leave a bunch of plastic on the ground for a super long time if I don’t have to. How does it work? – Julia W

Answer: It generally takes around eight weeks to solarize soil. Though this seems like quite an investment of time, it’s important to understand the benefits of soil solarization.

Many gardeners use solarization for two purposes. The first is to kill off any seeds of weeds. This helps keep your garden tidier and plants healthier during the growing season.

The other reason gardeners solarize their soil is to kill unwanted pests and diseases that cause harm to plants.

In some cases, soil solarization is the best method for curing certain diseases such as fusarium wilt, blight, bacterial canker, and potato scab.

Keep in mind, soil solarization works best in areas which receive full sunlight. The idea is the soil must get hot enough beneath the plastic to kill off the things which harm your crops.

In most cases, it’s best to practice soil solarization during the hottest months of summer because the goal is to keep the daily temperature around 110 degrees Fahrenheit between the top of the soil and six inches beneath the ground.

If you try to solarize your soil in cooler times of the year, the process may take longer as it will require more time to thoroughly heat the soil.

It’s wise to use a soil thermometer to check the temperature of your soil, daily, to ensure you’re meeting the desired temperatures.

You may also solarize loose soil or soil in containers. Instead of covering a large inground area with black plastic, place your containers or loose soil in black trash bags.

It’s best if the trash bags are layered. You must wait six to eight weeks for the process to complete, but the soil should reach temperatures well above 110 degrees Fahrenheit as long as the bags are in full sun.

Be sure to place the black bags on a hard, elevated surface to ensure air can flow around them to maintain the integrity of the bag. A pallet would be a good item to help with this.

You now know how long solarization takes, the temperature goals for the process, the best time to perform soil solarization, what solarization treats in your soil, and how to perform this method on traditional garden plots and container or loose soil.

Hopefully, this information will help you provide great care to your garden, keep your plants healthy, and your garden free of weeds.