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Naturally Weed-Resistant Lawn

by OCMGA Master Gardener Vicki Schilleman

Back Yard Vinyl Fence Outside Grass Lawn NatureEveryone wants the perfect sea of smooth green lawn with nary a hint of weed, bare spot, or discolored grass. Alas, easier said than done! However, here are 5 steps that will help create a beautiful and naturally weed-resistant lawn.

  1. Prepare the soil. Though they are seldom thought of that way, expanses of mown grass are actually very intensive gardens. Loose, fertile soil of the right pH is even more important for good lawns than it is for tasty tomatoes or lavishly blooming shrubs.
  2. Invest in the best seed, use enough of it, and plant it at the right time. The first defense against weeks is a turf that is thick enough to prevent them from getting the light they need to sprout and grow. The grass won’t be thick if you’re stingy with either quality of quantity, and it won’t fill in properly unless you give it a proper start.
  3. Think long term. Be sure the seed mixture comprises grasses that will be long lived, such as red fescues and bluegrasses. There should be only a very small amount of rye grass, if there is any at all. Rye grasses grow quickly, helping the lawn to look good fast and preventing the growth of some weeds. But because they are up so quickly, they steal nutrients, water, and light from slower-growing but more durable types. As a result, newly established turf has a lot of rye in it. This is fine for a short while. But even perennial rye dies out within a few years, and when it does it leaves a whole lot of room for weeds to move in. A sprinkling of rye can be used if you are the impatient type. But you’ll have better long-term weed control if you go for the slow stuff and hand-weed for the first year or so while the good grasses are settling in.
  4. Adjust the mower to the season. No matter what height you like your lawn, letting it get a bit shaggy in summer — a good 3 inches tall — will cut down on weeds. The taller gras provides more shade, keeping the grass roots cool and healthy while making it harder for weed seeds to sprout and find the light.
  5. Don’t water if there’s a drought. This may seem counterintuitive, and it isn’t entirely true: if you have an endless supply and can water the lawn thoroughly, by all means go ahead. But if water is limited, you’re much better off letter the lawn go dormant than trying to give it “just enough to stay alive.” Grasses naturally lie low and turn brown during droughts. They aren’t dead — they’re just sleeping. A small amount of water won’t be enough to keep grasses green, but it will keep the lawn green, because the watered weeds will thrive

Organic Weed & Feed

For those of us who become frustrated at the growth of weeds in our lawns when we’re using organic fertilizers, there is one help: corn gluten meal, a by-product of corn milling. It is quite high in nitrogen, which makes it a good fertilizer for grass. And it will prevent weed seeds from growing.

But — there’s always a but — that’s it. Corn gluten kills by drying up the baby sprouts as soon as the seed cracks open. It has no effect on perennial weeds (other than to encourage them) or on annual weeds that are already growing.

Furthermore, it must make good contact with the weed seeds in order to kill them, not a problem on bare soil but a tricky proposition if the grass is reasonably thick. It works best when the soil is warm, by which time many annual weeds have long since been up and about. And it lasts for only about six weeks, so you have to apply it frequently.

All that said, corn gluten is a relatively benign fertilizer, and it can help control annual weeds if you use it faithfully, from spring to fall, for a couple of years. It is nontoxic and, in home-garden quantities, safe for the environment.

Organic “weed and feed” for Lawns

Many gardeners are worried that the products being used to keep that beautiful lawn are, in fact, endangering the environment. With that in mind, then, there is a constant desire to use less damaging chemicals but, at the same time, retain a beautiful lawn. One solution may be corn gluten meal, a by-product of corn milling. It is quite high in nitrogen, which makes it a good fertilizer for grass, and it will prevent weed seeds from growing.

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Corn gluten meal being applied by a broadcast spreader

Corn gluten kills by drying up the baby sprouts as soon as the seed cracks open. However, it has no effect on perennial weeds or on annual weeds that are already growing. Furthermore, it must make good contact with the weed seeds in order to kill them — not a problem on bare soil but a tricky proposition if the grass is thick. It works best when the soil is warm, by which time many annual weeds have long since been up and about. And it lasts for only about six weeks, so you have to apply it regularly.

Corn gluten is a relatively benign fertilizer, and it can help control annual weeds if you use it faithfully, from spring to fall, for a couple of years. It is nontoxic and, in home-garden quantities, safe for the environment.

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One of my favorite hand tools for “popping” those weeds out of the lawn

There is no panacea, however — you cannot go totally organic and control 100% of weeds in your lawn unless you have some handy tools for digging out the weeds. There are a lot of really good hand tools to help you tackle those weeds, though, and maybe a cleaner environment for our kids and grandkids is worth the extra effort.

 

Crabgrass Prevention

by Lisa Johnson, Horticulture Educator for Dane County

Forsythia is one of the harbingers of spring. The bright yellow blooms indicate that spring has finally sprung! Forsythia’s bloom coincides roughly with soil temperatures at 55F at 1/2 inch depth — the conditions crabgrass seeds need to germinate. So, when forsythia blooms, it is time to apply pre-emergent crabgrass products.

The key to a pre-emergent is to apply and water in before crabgrass seeds germinate, but not too far before, because many products available to homeowners have a limited window of efficacy, usually about 90 days.

Products available to professional lawn care companies have a longer period of efficacy, so you often see companies applying these products earlier than when the forsythia blooms.

Pre-emergents don’t actually kill the seed; they create a chemical barrier that doesn’t allow seeds to germinate. If the soil is disturbed and the barrier disrupted, germination may still occur.

One problem with pre-emergents is that they will also prevent desirable lawn grass seed from germinating, if it is sown while the herbicide is still active. So, be careful when and where you apply the pre-emergent and where you seed later.

If you have dead patches of lawn in spring and want to reseed there, avoid using a pre-emergent in that area. The best time to sow lawn grass seed is actually late August or early September, but if you need to seed in spring, just make sure to keep the seed watered, if it is a dry spring (the same, if it is a dry fall). Wait until the seed has germinated and is about 2 inches tall before fertilizing. The lawn, in general, should not be fertilized until Memorial Day.

by Lisa Johnson, Horticulture Educator for Dane County

A Seedy Character

Written by Master Gardener Bev Kindschy

Crabgrass is one of the most common weed problems in lawns. Its gets its name because the leaves form a crab-shaped design.  Crabgrass seems to appear in close-mowed lawns and bare spots and in the fall it turns a brownish red color.  Seed heads show up in the summer and fall and stems will continue to spread unless they are stopped.  The best prevention is dense, healthy, thick turf, which prevents it from invading because crabgrass seeds need light to germinate.

Crabgrass

However if you haven’t had that success with your lawn, you may need to go on the offensive by treating your lawn with a preemergent herbicide in the spring, to prevent the crabgrass from germinating and spreading You will want to do this in mid to late April when the ground temperature is about 52 degrees.

To check the ground temperature in this area, you can reference www.greencastonine.com.  Click on Agronomic Tools, Soil Temperature Maps.  You’ll see the date in the upper left corner.  Click on Wisconsin, and zoom in to see the temperatures.  soil map

If you don’t get your preemergent down before the warm temperatures are here, you’ll need to wait until next spring.  FYI…One crabgrass plant is capable of giving off 100,000 crabgrass seeds.  All the more reason to get rid of this weed.