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burn black dirt to kill weed seed

There is lots of work involved since soil solarization entails getting to the root of the problem, underground.   And we will not be taking the shortcut of using herbicides, so that means a bit more work. But if you do not mind getting your hands dirty, then let’s roll up our sleeves and begin stopping our weedy foes in their tracks.​

If there are shrubs and trees present, cut them down with an ax or chainsaw. The ground needs to be smooth before you begin soil solarization (since you will be spreading plastic over it), so you will also have to remove the stumps left behind. If you are looking for a cheap way, use a tool called a “mattock.” Dig and chop your way with the mattock under the root-ball to access and remove the taproot. Warning: this is hard work and may be feasible only for smaller stumps.

Preparation

Of course, if you use an organic mulch (such as a bark mulch), it will eventually decompose anyhow, becoming fertile ground for weeds. What can you do? Well, you had better keep new weeds pulled, faithfully. Vigorous roots pushing downwards can stress landscape fabric and breakthrough. On the bright side, these weeds should be relatively easy to pull, since mulch is a lot looser than dirt, and weed roots will not become impossibly entrenched.

Perhaps you are wondering at this point, “Why do I need soil solarization? Why can’t I just lay landscape fabric at this point, punch some holes in it, plant my new plants and then cover with mulch?” Well, the reason you can’t is that your job of killing weeds has only just begun. Weed seeds that you can’t even see are lurking beneath the surface, just waiting to sprout. If the weeds are vigorous enough, they will find a way back to the light (remember, the integrity of the landscape fabric will be compromised when you punch holes in it for your new plants). So you need to kill those seeds before you proceed with laying landscape fabric. And that is a job for soil solarization.

First hack down the tall vegetation with a sickle, power trimmer, etc. But before doing so, make sure you know how to identify poison ivy, poison sumac, etc.

If your weeds regrow, then you have a persistent root that you need to dig out. Use a spade or digging fork to dig up persistent weeds by the roots. Remove as many root pieces as you can.

You’ll still need to manually pull out weeds during the season. It may not be your favorite chore but it’s oddly therapeutic and almost meditative for some of us! Wear waterproof gloves and consider a comfortable kneeling pad or camp stool for extended weeding sessions.

5. Hoe Them Down

If dealing with weeds is too much of a hassle, at least resolve to keep them from setting seed. Once a week, use a grass whip or string trimmer and cut off their heads before they flower.

For persistent or numerous weeds, exclude light! Cover soil with dampened newspaper (black ink only) or brown cardboard (with any tape removed). Then cover that with 2 inches of straw or compost. This ensures that weeds don’t get the light they need to grow. There will still be some persistent perennial weeds that survive but most will not grow through, hence, very little weeding necessary. Plus, you’ll save on water and have happy worms and soil.

This works best, of course, when you are starting a new garden bed or a new garden space. Watch Janice Stillman, editor of The Old Farmer’s Almanac lay down a few layers of newspaper, wet it, adds mulch on the edges of the newspaper, and dumps compost on top of the newspaper bed! You’ll love having almost no weeds to contend with and as a bonus it helps build the soil. It couldn’t get any easier than this.