Salt is organic, and it won’t hurt you if you touch or swallow it. So, some gardeners recommend it as a weed killer. The problem is that salt persists in soil and inhibits plant growth. Anyone who has tried to nurture plantings by the side of a road that gets salted in winter can attest to this.
So, how do you get rid of weeds safely for the environment and your plants? We are going to cover some of the safer options. This article lists a few minimally damaging ways of dealing with weeds, and some of your safer organic weed killer options.
We’ve arranged this article based on advice of weed control options you should try first:
- Weed Prevention
- Boiling Water
- Organic Herbicides
Weed Prevention Tips
There are many things you can do to stop weeds from getting a foothold in the first place.
Plant Close Together Bare soil is an open invitation to weeds. Try to keep it covered. Space your garden plants close enough together so that mature plants will fill most or all of the growing space and shade out any competition.
Mulch Mulch open areas with leaves, compost, straw or (non-herbicide) lawn clippings if you’re going to plant in them later. Or, mulch with sawdust, bark or stone if you just want to walk on them. Plant thick-growing cover crops like clover or buckwheat that can outcompete weeds.
Remove Weeds Before They Seed Try to catch weeds before they go to seed. Flowering weeds are easy to spot, and removing one flowering weed can stop you from having to remove dozens of weeds that will come up from its seeds.
Killing Weeds with Boiling Water
Very few weeds are tough enough to resist a drenching with boiling (or just-off-the-boil) water. Make sure you cover the root area, not just the outer leaves. Boiling water leaves no problematic soil residues; just make sure you don’t spill any on yourself. For obvious reasons, don’t do this right next to plants you want to save.
3 Organic Herbicides that Won’t Wreck Your Garden
- Corn Gluten Meal Corn gluten meal can be applied to bare soil to prevent the germination of weeds. It remains effective for about 6 weeks after you put it down. Corn gluten meal will not damage existing weeds, and it can hinder the germination of most desirable plants as well as weeds. It does not leave toxins in the soil and as it breaks down it adds nitrogen to feed the next generation of plants. It can work very well on established lawns, feeding the roots of the already established grasses while inhibiting the germination of weed seeds.
Some gardeners and researchers say that corn gluten meal is not very effective at preventing weed germination, especially in wet climates, since corn gluten meal works partly by drying the soil out so seeds die of thirst when they try to sprout. Get a form of corn gluten meal that is labeled as a preemergent herbicide, not as an animal feed additive–the kind sold as animal feed has weaker effects on weed seeds.
- Molasses Two or three applications of a mixture of 1 cup of molasses in 1 gallon of water will help prevent most weeds from seeding. Molasses can help to boost microorganism populations in your soil and is not toxic. Molasses helps increase phosphorus in the soil, which creates a soil environment unlikely for weed seed germination.
Here’s how to apply molasses and its other benefits:
- Vinegar Vinegar can kill young weeds. It withers leaves dramatically but tends not to kill roots unless applied in a very strong solution. Vinegar kills with the strength of its acids. Some gardeners recommend a vinegar solution that contains 10% acid (which may be sold as pickling vinegar–stronger than your normal; household vinegar); others call for a 20% solution. The 10% strength may not kill established weeds, and the 20% strength is expensive. Both, but especially the 20% solution, will lastingly acidify your soil, making it less hospitable to plants for some time to come. So, consider this your last resort.
Want to learn more about organic weed control?
An Organic Weed Control Toolbox by Mark Schonbeck, Virginia Association for Biological Farming Improving Garden Soil: Milk and Molasses Magic by Mother Earth News
