With more and more people getting back to vegetable gardening, there has been an increased interest in all types of organic gardening products. One aspect of our gardens that uses a lot of chemicals is lawn care. We really like lush green weed free lawns but weeds are actually a symptom of other problems not the cause. If we just changed a few things about how we care for our lawns, we could reduce our reliance on chemical controls.
The cheapest herbicide is simply raising the height of the mowing deck on our lawn mowers. This does two things: 1) Increases photosynthesis due to greater leaf surface area resulting in healthier plants with deeper and denser root systems and 2) Increases rhizome development which is how most grasses reproduce. Both of these things lead to reduced weed pressure in the lawn because there is now a lot less space for the weeds to get established.
The recommended mower height for blue grass, which is what most northern lawns are, is 2½ to 3 inches. It is also recommended that not more than ¼ to ⅓ of the blade length be cut at any one mowing. So if you happen to miss a week or the grass is growing faster than you can keep up with it, raise the mower deck and gradually bring it down so that you get to the desired height over time.
Another factor in weed control is soil fertility. Most weeds actually prefer less fertile soils while our lawns need lots of nitrogen to grow well. A good example of a “weed” that grows well in less fertile soils is clover. Clover is a legume or nitrogen fixing plant. It doesn’t need extra nitrogen because it makes its own. Creeping Charlie, another noxious weed tho not a legume, is also a plant that grows well in less fertile soil. The presence of these two plants are a symptom of low soil fertility. The University of Illinois recommends 3-4 pounds of nitrogen per 1000 square feet per year. You can actually add about 1 pound of nitrogen per 1000 sq. ft annually by not bagging your lawn clippings.
Will changing your lawn care practices get rid of weeds immediately? No, but you will notice the difference over time and will able to feel good about your lawn’s impact on the environment.