How To Control Dandelions and Other Weeds In The Lawn and Garden Organically
On April 22, 2009, Earth Day, Ontario banned the sale and use of chemical pesticides for cosmetic use. For many who still hope for a weed free lawn, this will pose a significant challenge.
Fortunately, there are a number of ways to control dandelions and other weeds organically, although the results are not perfect and often require more labour.
Mow High
To fight weeds in a chemical free environment, your lawn needs to be healthy and thick enough to stop most weeds from germinating and choke out any weeds that do grow.
Mow your lawn as high as possible (ideally at least 3 to 4 inches). Mowing high chokes out weeds and shades the ground preventing new weeds from germinating.
Hand Weeding
Even on a 2-plus acre property I am able to keep up with most of my weeds by hand. In the gardens I pull all weeds by hand, usually after a rain. I try and keep up by weeding a small amount each time I am out. It's become such a habit that I actually have to be careful when we have visitors not to bend down and pull up a weed while I am talking!
Whenever I am working in the gardens I always carry three key weeding tools plus a pail to drop pulled weeds in.
For lawn weeds, other than the creeping variety, I like a plunger type weeder. The version I have is from Home Hardware but there are many other models that work well. It allows me to pop out any weeds I see in the lawn as I am walking along. This weeder works well on any tap root or clump type weeds including dandelions, black medic, plantain and non-creeping clover.
Although some large dandelions may have to be removed more than once, it is relatively easy work. Insert the three point end into the ground, twist one or two turns until the root seems loose, lift to remove the weed. Then just push the plunger to eject the weed into a bucket. In just 10 minutes you can quickly fill a pail full of weeds from a large area.
The second tool I use is a traditional dandelion fork weeder. I use this tool in the gardens for loosenng the soil under almost any type of weeds, including grass. Then I just lift out the weeds and shake off any soil or mulch. This tool also works for larger dandelions in the lawn however I find it quite hard to insert past the lawn roots. A longer handled version might work better in the lawn but I'll stick with my plunger model for that.
My third favourite weeding tool is a hand cultivator. In the gardens this tool works well where there are a lot of small, shallow rooted weeds. This is also an effective tool for those pesky creeping weeds in the lawn like Creeping Charlie. Scrape along the lawn from the outer edge of the patch to the inside, from many directions. Carefully pull up any pieces, trying to get all of the roots. Overseed with some grass seed to help fill in the lawn before more weeds grow back.
Vinegar Herbicides
For spot treatment or for small areas of pure weeds, many people have reported success with 20% vinegar sprayed on the foliage. To a gallon of vinegar, mix a tablespoon of liquid dish soap and two tablespoons of molasses as wetting agents. Apply full strength from a hand sprayer. Be careful not to get any spray on you, in your eyes or inhale it since it is an acid. Be aware that vinegar is non-selective, if sprayed on your lawn it will damage the lawn as well. I have heard that heat makes it work better. Despite this, some weeds may require more than one application.
Boiling Water
Boiling water works well on weeds that grow among rocks or between patio stones. Again, boiling water will kill all plant types so I would not recommend this method for the lawn. Some weeds often take two to three applications but this is definitely a non-harmful weed control method.
Propane Weeding Torch
I have not used this method myself as I don't see the benefit in trading a chemical control for one that burns fossil fuel, however many say it works very well in patios. This tool burns off the top of the plant, but usually needs more than one application to be successful with tough plants like dandelions. Generally it doesn't kill off the root, which means the plant can re-grow.
Corn Gluten As A Pre-emergent
Corn gluten can be applied as a pre-emergent. Corn gluten has an enzyme that inhibits the production of root hairs on newly germinated seeds. This means they cannot absorb water as well and as a result do not take hold and will die. The downsides? In wet years the seed will likely still survive. The upside? Corn gluten also provides 9% nitrogen to help your lawn grow healthier and thicker.
Apply corn gluten in spring around when the forsythia are blooming and before the lilacs bloom as this is prime time for dandelions to germinate. Be aware that corn gluten does not discriminate among seeds so it affects your ability to over-seed your lawn. It also may build up in the soil thereby affecting your ability to over-seed in future years.