Harness the Suns Power for Simple Soil Sterilization

Solarization sounds like a highly technical and scientific process, but it’s actually an easy and painless technique for killing weeds or green manure cover crops without work.

Solarization - Use the Heat of the Sun to Control Weeds

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This method prepares the ground for flower gardens or other landscaping projects without using chemicals, breaking your back digging or the need for heavy machinery.

Solarizing can be done on your pathways, driveway or mulch beds and consists of covering the area with plastic or some other material that doesn't allow light to penetrate for a while.

I re-purpose floor mats, anti-fatigue mats and runners that I salvage from the recycle center; black or dark colours work the best as they attract more heat from the sun.

The weeds or other plants underneath the plastic die and melt into almost nothing.

The beauty of this method is that beneficial micro-organisms and micorrhizae aren’t killed but harmful diseases or pests can’t survive the heat.

Sometimes solarization is referred to as 'sterilizing' the soil, but it's more a pasteurization method which allows the good bugs to survive unharmed.

There are two basic methods: using clear plastic or black plastic.

I use a short piece of black lumber wrap that gets moved around every week or two to keep the pathways clear of weeds. The plants deprived of sunlight get pale and leggy, and then when they’re exposed to the hot sun again they shrivel up and die.

It’s important to use this solarization technique in the hottest part of the summer for best results. In some cases it will take several repetitions over the summer.

For solarizing a new bed, use the lasagna gardening technique with a twist. Layer the organic materials that will form the bed, water well then cover with plastic.

Solarization kills weed

The added heat and moisture will turn the bed into a garden in double quick time, allowing you to plant that much sooner. This method also works for pasteurizing compost to kill weed seeds, making it safe for use in potting soils and for seedling mixes.

I find used mats, but if all else fails, buy them new, like this beveled edge rubber mat from The ones labeled Anti Fatigue are thicker and much more durable, and the ones that are beveled stay flat and don't create a tripping hazard.

After you solarize the area and remove the mat to use elsewhere, you can plant succulents and other plants closely spaced, mulch with your preferred mulching material (I recommend lava rock).

Continually moving the mat is essential.  Once the plants have died off underneath, move the mat to cover another area. In time, the weeds will all be done away with, without the need for dangerous chemicals.

Bracken likes to sit on the mat, and quite often has a nap there!

I build or renovate new areas like this on a fairly continuous basis, which keeps weeds like couch grass, chick weed and dandelions to a minimum.

After using this method for a while, you’ll probably wonder what you did before, as all the work is done for you.


Xeric Gardens

Xeriscape Gardening

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