Step 8 - Organic Weed Control
What is the best way to deal with weeds in your lawn?
A. Chemical herbicide sprays
B. Pre-emergent weed and feed dry product
C. Pull the weeds by hand
D. Establish healthy turf conditions that prevent or discourage weeds from growing in the first place
The organic approach to lawn care is rooted in the strategy of preventing problems before they occur by first establishing the fundamentals for healthy turf. Therefore, choice "D" is the best answer to the question above. Rather than killing weeds after they appear, it is best to avoid using any chemical poisons and instead, establish the conditions that prevent weeds from germinating in the first place. Since the goal is to establish healthy turf conditions, it is important to follow what we call in this 12 Step educational series, the Organic Lawn Care Fundamentals, which include: mowing high, leaving grass clippings, choosing low-maintenance seed, over-seeding thin and bare spots, and following the Goldilocks Rule of avoiding over-doing it or under-doing it with the application of fertilizers, watering and balancing soil pH.
According to a Long Island-based organic landscaper with over 20 years of experience, "Weeds in your lawn are messengers. They are telling you the story of what is wrong in your soil." Eric Pomisel, the owner of Gro-Kind Organics in Bellmore, who is a frequent speaker at seminars on organic land care, and has been featured on News 12 and in Newsday continued, "Mow tall to keep weeds from multiplying. Mowing low stresses grass, and encourages weeds to come back stronger. Don't over fertilize, or over water, that helps grow weeds, much more than it helps the grass."
So the best way to fight weeds is to establish healthy turf by following the organic lawn care fundamentals. Taller grass shades out weed seeds, so remember to cut grass high, at 3.5 inches. Too much fertilizer, especially with fast release nitrogen, can end up feeding opportunistic weeds that take advantage of the abundance of nitrogen. However other weeds grow better than grass in soil with too low nitrogen. If you leave grass clippings on the lawn and have clover mixed in with your grass, you will establish a self-sustaining system and won't need to add much if any fertilizer. If you do still have thin and bare spots, use slow-release, organic fertilizers in the proper amount, no more than 1 lb of nitrogen per 1,000 square feet per year. Over-seed, especially in the fall, this will give your grass a "head start" ahead of the weeds the following spring. Test your soil pH and keep it balanced at between 6.0 and 6.5; many weeds prefer more acidic soil. Apply good quality compost to add organic matter, beneficial microbes, and to improve soil structure. In many respects, the fundamentals are basic; grow longer, thicker turf and it will keep the weeds out.
If you follow these fundamentals, every year you should see fewer weeds in your lawn. During the transition from chemical-lawn care to organics, especially if you have been using weed and feed products, or herbicides, you may see weeds pop up that used to be suppressed by chemicals. During major repairs to the lawn, opportunistic weeds will often establish themselves in bare and thin spots. Be patient, it can take some time to remediate the underlying problems that encourage weeds. If you panic and use a chemical herbicide, you will undo much of the progress you have made toward building a healthy soil ecosystem that supports your organic lawn.
The difference between a plant and a weed is in the eyes of the beholder. In fact, the Pilgrims brought over dandelions from the Middle East for their medicinal properties. With more vitamin C than tomatoes and more vitamin A than oranges, these 'weeds' used to be incredibly important and dandelion salads can still be found on better restaurant menus.
Of course, every lawn has the chance for the occasional dandelion to pop up. To control sporadic weeds, you can pull them by hand, or with a tool like a weed fork or a 'weed hound'. Always cover the bare soil left behind from pulling a weed by spreading compost, then apply grass seed on top of the compost. If only the top is removed or a small part is left, dandelions will re-sprout. Remember dandelions spread through windborne seeds. Mow off, or pick off the yellow blossoms of dandelions before they go to seed to prevent more dandelions next year. If you mow them after they have their big white head of puffy seeds, you will just spread them. At that point you have to pick them carefully and place them into a bag immediately to try to contain the seeds.
For larger patches of annual weeds, like chickweed, rake the patch down and cover it with compost. Seed grass over the compost. This will smother the weeds and establish new grass in the spot.
When you apply lime to adjust the pH of you lawn, it will not only reduce crabgrass, moss, and plantain, which all prefer more acidic soil, it also adds calcium to your soil, which will help reduce dandelions, which thrive in lower calcium conditions than turfgrass prefers. Lime, which can be applied anytime, can therefore help prevent three different types of weeds.
Research shows that in two years, proper mowing and fertilization can control crabgrass as well effectively as chemical herbicides. If you have areas in your lawn where you have not been able to get crabgrass under control, corn-gluten can be used as a pre-emergent measure to prevent crabgrass. Timing is critical. Apply corn gluten when forsythia first shows color. Spread it on areas where you know you have had trouble controlling crab grass in the past. Corn gluten will stop turfgrass from germinating too, so if you are re-seeding, wait at least 6 weeks after you apply corn gluten. Therefore, to plan things out optimally, seed in the early spring at least 2-3 weeks before applying corn gluten so that the grass seed has germinated and is not effected by the corn gluten.
Clover: A Friend Becomes a Weed
Is clover our friend or foe? Clover is ideal for a lawn. It reduces or eliminates the need for fertilizer because it 'fixes' nitrogen (taking it from the atmosphere and incorporating it into a form that plants can use). Clover is highly resistant to disease, drought, and turf insects; it will keep your lawn green, even when turfgrass is highly stressed. So why has this beneficial plant been unfairly labeled a weed?
We have all read books and watched movies about alleged conspiracy theories throughout history, such as the Kennedy assassination, or whether oil interests sabotaged the electric car, but you may not have heard about the 'conspiracy' to turn clover into a weed.
The evidence of the conspiracy starts with the fact that clover helps turf to fix nitrogen, it was always a part of lawns, and was even listed on the grass seed bag as one of the seeds intentionally mixed with other lawn seeds-until the discovery that a powerful herbicide could kill broad-leaf clover without killing turfgrass. (The pesticide was the highly toxic 2,4-D, which was one of the chemicals in Agent Orange, used to defoliate jungles in Vietnam.) Since the toxic formula killed the clover along with weeds, advertisers solved the problem by classifying clover as a weed rather than grass. This was achieved primarily through advertisements that told mothers that clover attracted bees that could sting children and fathers that clover lawns were unkempt.Suddenly, nobody wanted a neighbor to look over the fence and find the dreaded clover in your lawn, as TV ads portrayed. Due to the power of influential advertising, the benefits of clover were effectively forgotten within only a few years.
The conspiracy was ingenious not only in convincing people to buy a highly toxic pesticide to kill something that was actually beneficial to the lawn, but by eliminating clover, homeowners were now also urged to buy more fertilizer to make up for the nitrogen that clover used to pull from the air into your lawn-for free.
Yet despite the desire of pesticide and fertilizer companies to label clover a weed, it still has inherent value and should be part of your organically maintained lawn.
Weeds in Pavement
Some organic weed killer products do exist, they contain vinegar, citrus, or some combination and they can be effective on weeds that are young and not well established. They work best in hot, dry days with full sunlight and are often used for weeds growing in cracks in pavement. Although it is good to know these tools exist, generally speaking, organic landscapers do not rely on these products much as their strategy is to prevent weeds by establishing good lawn care fundamentals.
Is this the right place for grass?
Lastly, in areas where you have significant, recurring problems growing thick turf, you may want to consider other landscaping options. In his book, The Chemical-Free Lawn, Warren Schultz advises, "Don't try to put a lawn where grass won't grow; pave traffic areas and paths, and plant groundcovers in heavy shade."
- Read Your Weeds. This pdf will help you figure out the messages weeds are sending about your lawn's soil conditions.
- Handbook of a Successful Ecological Lawn Care by Paul D. Sachs
- Chapter 7 of Chemical-Free Lawn is an informative resource for organically managing many types of weeds. The Chemical-Free Lawn by Warren Schultz
- Managing Weeds Video
- 5 Steps to a Better Back Yard (Clover)
- 6 Reasons not to kill clover
- Weed Management on Organic Farms
- Removing Weeds without chemicals
- Vinegar and Citrus based weed killers
- Killing Dandelions Organically
Long Island Organic Landscapers
Although it's easy for the average homeowner to maintain their lawn organically, some may too busy and wish to hire a professional. In that case there are thousands of landscapers on Long Island to choose from, but only a small but growing number of experts who can maintain your lawn and landscape without the use of chemical pesticides. They can be found here.