Tuesday, September 21, 2010

Please don't poison my planet - eco-friendly options for weed control

I just saw a post on a “green” blog that started out by saying that now is a good time to “Spray lawn weed killer.”

My reaction: ACK!

In keeping with my personal “don’t poison the planet” rule, I went searching on the Internet for some non-toxic ways to control weeds. I haven’t tried most of them myself and I welcome input from anyone who has about what has worked for you and what hasn’t in your yard and gardens.

Hand pulling - Admittedly, not the easiest or most fun, but certainly the least toxic to the planet. Hand pulling weeds is also one of the many garden chores that help to burn calories. Weeds should be pulled before they go to seed and care should be taken that the whole tap root is removed, not just the weed tops. Weeding forks are excellent tools for getting the whole weed. There is a very extensive list of various weeds in a Chemical Free Lawn and Garden book that I own, listing control methods for the different weed species. I’m not sure why they took the time or the space in the book to provide the list of different weeds because as far as I can tell, every single weed says either “hoe, dig or pull”.

Corn gluten meal– Although it won’t kill weeds that are already present, corn gluten meal is a safe pre-emergent control, which means that it prevents weed roots from developing so the seedlings die before they can take over your lawn or garden. It is safe for people, pets, fish and wildlife. Products which are based on corn gluten as the main ingredient are available under many names, including WOW and Concern.

Solarization– If you have a specific area that you can leave alone for awhile, you can kill everything (weeds included) by wetting the area and covering it with clear plastic sheeting. The edges must be sealed to make the whole thing airtight. This process is called solarization and it works because the rays of the sun heat the soil to temperatures as high as 140 degrees at the surface and up to 100 degrees as far down as 18 inches. Keep in mind that while this method kills pests and diseases in the soil, it will also kill other plants and any insects, earthworms or other beneficial critters that don’t have the opportunity to crawl away to another location. For more information, read the fact sheet: Going Solar to Set Your Soil Straight.

Use boiling water - For weeds in sidewalks, driveways etc, you can pour boiling water directly on the weed. You can also use boiling water in gardens but keep in mind that it won’t be great for earthworms, plants that you want to keep or any beneficial creatures that are hiding out under the soil. For stubborn perennial weeds (including poison ivy) you have to expose the roots and pour on the boiling water. Don’t rebury the roots, as keeping them exposed helps speed their demise.

Weed torches – Small, propane powered torches are available specifically for burning weeds out of cracks and crevices in sidewalks and driveways and will even work in gardens and lawns. Keep in mind that it is the heat, not the flame, that will kill a weed and the heat can affect plants well beyond the visible flame. Also, anything that is too dry can catch on fire, including mulch, dry leaves, your sneakers, etc.

Household vinegar– A recipe that I found on the Internet said that you can control weeds by mixing 1 cup vinegar with ¼ cup lemon juice, pouring it into a spray bottle and spraying it directly on weeds. This mixture is said to control herbaceous broad-leaf and grass weeds, including chickweed, ragweed, plantain, crab grass, quack grass, and wild carrot and results are said to be obtained in as soon as two hours. I also found several sources that warned that vinegar and lemon will both upset the natural chemistry of the soil and make it difficult for other plants to grow.

Using mulch - Mulch can help to smother weeds in a garden by blocking sunlight. This keeps weed seeds from germinating and young weed seedlings are smothered.

If you have found eco-friendly products or methods that help control weeds, please let us know by leaving a comment. My husband and I are pretty tolerant of most weeds in the lawn (many visiting critters seem to like to eat them, including our neighbors goat that sometimes gets loose and wanders into our yard). In our gardens, we just hand pull and use mulch.

For more information:
Pesticide Alternatives, Montgomery County Watershed
A Corny Solution for Weeds (pdf file) about corn gluten
Going Solar to Set Your Soil Straight (pdf file)
Weed Control – Fairfax County

Online ources for purchasing products :
Gardens Alive
Planet Natural


  1. There is a product called "horticultural vinegar" for organic weed control- instead of 5% acidity like household vinegar, it approaches 50% acidity, I believe. I have not used it and understand you need to wear gloves and avoid skin contact, you could get an acid burn.

  2. I have actually tried all of the above mention methods except the torch. They all work, but have different applications, ie. dandylion in sidewalks, or solarization for large areas, or hand pulling plantain in the grass.
    Any of these are effective for a homeowners and smaller properties.
    I take care of numerous homes and commercial properties and the only afore mentioned methods that are viable are corn gluten for pre-emergent weed control and a general herbicide called burn out made from food grade vegetable and clove oil. Burn out works better than horticultural vinegar and boiling water, but is not as available….
    The ground doesn't like to bare, but good soil management and mulch go a long way to controlling weeds.

  3. I have used a mixture of Vinegar and hot water, which works very well. Within days, the weeds are dead. Especially, weeds that grow in sidewalk and asphalt cracks(driveways).


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