If you have soil that's been contaminated by lead, you know that it's probably not safe for vegetable gardening and it can also be a hazard to children and pets who play on your property.
Many homeowners install raised garden beds and bring in new soil and compost to try to solve the problem, but you can also use plants to naturally remove the lead from the soil.
The process of using plants to remove toxins from the soil or to render them harmless is called phytoremediation.
Some plants are so effective at phytoremediation that they can be smelted after being used to clean up water-soluble metals at extremely contaminated sites and the metals can be extracted back from the plants.
The USDA explains how one plant physiologist is using plants to clean up soil:
Kochian's cost-effective "green" technology uses plants to "vacuum" heavy metals from the soil through their roots. He says, "Certain plant species—known as metal hyperaccumulators—have the ability to extract elements from the soil and concentrate them in the easily harvested plant stems, shoots, and leaves.
Different plants are best suited for removing different toxins, as well.
It is important to note that these plants may not remove all of the toxins from soil in one growing season. Lead tends to remain in soil for a very long time, which makes it harder to remove from your soil. Factors such as the rate of growth of the plant and the amount of lead in your soil will influence how long it takes to fully clean up a site.
A heavily contaminated industrial site can take up to 14 years to fully remove all traces of lead with phytoremediation. If your soil is heavily contaminated, be sure to grow edible crops in raised containers until tests show that lead levels are safe.
That said, phytoremediation is an excellent, natural, low-cost way to detoxify your land -- especially if your property has only mild to moderate contamination.
Click on the photos to view seven of the best plants for removing lead from your soil, and learn more about each one.
Remember not to eat or compost plants that you grow to remove toxins from your soil! Be sure to dispose of these plants properly after removing them, or you'll simply relocate the lead to another part of your yard (or worse, your body).
Stay tuned in this column for upcoming articles highlighting plants that will remove other toxins, such as arsenic, pesticides, uranium and mercury.
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