• How To Prevent Crabgrass

    Read Now - Act Soon!

    We don't offer lawn care and landscaping services at Handyman Connection®, but we're often asked for advice about it and we've certainly spent our share of time with lawnmowers and spreaders.  One question has popped up so often we thought we'd address it in our March newsletter:  How to Prevent Crabgrass.  If you plan now and apply crabgrass controller when you see the natural indicator we'll tell you about in this article, you can have a beautiful lawn that's almost entirely free of this common, ugly but unwanted weed. 

    What is Crabgrass?

    Although crabgrass can seem like the plant that never dies, it is actually an "annual" plant, which means it doesn't survive the winter and instead dies off each year, with new plants sprouting from seeds.  If you see a plant in your lawn that has low, spreading stems that are very thin and "spindly" and broad, flat leaves that spread out from a center, it is probably crabgrass.  Crabgrass is one of the most despised invasive lawn plants, yet it is one of the most common weeds you are likely to encounter.  There are two main species of crabgrass in the U.S. and over 300 around the world.  The bad news is that if you see crabgrass, it often means your lawn needs some attention. 

    Crabgrass is a Symptom of a Potentially Bigger Problem

    A healthy lawn with dense grass can actually choke out crabgrass and prevent it from sprouting and taking root, but even a healthy lawn can have a few bare spots that leave a place for crabgrass to take root.  But if you have more than a few plants, it's time to get serious if you value a nice-looking lawn.  We won't go into all the things you should keep in mind for lawn care, but the biggest mistake we see is cutting the lawn too short.  We favor keeping lawns cut to 3" - 3.5" in the spring and fall and 4" - 4.5" in the summer, but find that most people cut their lawns much shorter.  And by the way, a lawn that's left longer actually grows slower than a short lawn, so you don't have to cut it quite as often.  If you aren't cutting your grass too short, large amounts of crabgrass are a sign of lawn problems that require your attention, but we don't have space to discuss those in this article.

    Use a "Pre-Emergent" Controller

    Back to what you need to do this spring...  The important thing to remember is that crabgrass can sprout before grass seed, and that it can keep sprouting for many weeks.  Crabgrass starts to sprout when the soil temperature is only 54 degrees, while most desirable grasses require temperatures in the low '60s.  This means that if seeds for lawn grass and crabgrass are both sitting in that bare spot in your lawn, the crabgrass gets a head start of at least a week or two, and sometimes longer.  This is why you need to act early in the year to control crabgrass, by applying a "pre-emergent" controller.

    The term pre-emergent simply means that it is used before the plant fully emerges, or starts to take root, instead of killing the plant once it starts to grow.  A single crabgrass plant can produce over 150,000 seeds, so stopping the seed from properly sprouting is one of the only ways to control a large amount of crabgrass.  There are a variety of pre-emergent controllers available, but we divide them into two main categories, which we'll discuss in a moment.  Think of a pre-emergent controller like a shield that goes over your lawn.  If you put that shield down early enough, you prevent the crabgrass from "infecting" your lawn.  But digging in or raking the lawn down to the soil will break this "shield", and make your pre-emergent controller  lose its value.  If you plan to dethatch or otherwise disturb the soil in your lawn, do so before your put down your pre-emergent crabgrass controller.

    WHEN to Apply the Crabgrass Controller

    This is very important!  If you don't apply the crabgrass controller early in the season, many seeds will already have sprouted and your prevention efforts are weakened or even doomed.  This is the biggest mistake people make in controlling crabgrass, but in our area of eastern Pennsylvania (and around much of the country) nature has provided a very simple reminder.  When you see forsythia start to bloom, put down the crabgrass controller!  Forsythia is the bush that produces those beautiful, bright yellow flowers all along its stem in early spring.  This is a very common plant in our area, so it's hard to miss this reminder.  And if you don't have your crabgrass controller down by the time the lilacs start to bloom, you're in for a season of crabgrass if your lawn isn't sufficiently healthy to otherwise choke it out.  So, for our area, plan on getting the spreader out in late March or early April.  You should also think about putting down another application later in the year to prevent later crabgrass seeds from sprouting.  Crabgrass controllers last about 90 days or so, which means we like to put down another application in late June.  That gives us protection until well into September, which is when we like to put down fresh grass seed (grass seed grows much better in autumn than in the spring, but that's another article).

    OK, So What Product Do I Apply to the Lawn?

    Here you have two main choices:  Chemical, or Organic / Natural crabgrass controllers.  Now, we don't want hate mail and this can be a controversial topic.  Personally, we admit to using chemicals in the past with great success but we are moving quickly away from this approach and plan to develop an organic lawn over the next few seasons.  But this is your choice!  All we ask is that you at least read the directions and follow the manufacturer's directions to avoid over-application of any chemical you put on your lawn.  There is growing evidence that over-use of chemical fertilizers and lawn treatments are having an effect on our environment, which is why we're personally going organic.  But again, it's your yard, and your choice.

    If you opt for a chemical (synthetic) crabgrass controller you can either purchase just the controller, or you can purchase a combination product that contains the fertilizer and the controller, commonly sold in home and garden centers and at your local hardware store.  Please make sure you are purchasing crabgrass controller, NOT a weed-control product designed for dandelions and other broadleaf plants.  These are different products, and many people confuse the two because home centers are notorious for putting weed control products out too early!  It may help them sell more weed controller, but those products won't help you control crabgrass, and they likely will have little benefit until a bit later in the year. 

    Chemical-type crabgrass controllers come in granular form and are applied using a lawn spreader according to the manufacturer's directions.  Unlike the weed killing products that are applied later in the year, the lawn can be dry when pre-emergent crabgrass controller is applied unless the manufacturer says otherwise.  Most crabgrass controllers should not be applied in areas where you intend to also plant grass seed within the next several weeks because most will also prevent grass seeds from sprouting.  There are controllers that affect crabgrass and not grass seed, but you must be certain that this is what you are applying unless you want to waste a lot of money and time.  Read the package!

    For natural / organic crabgrass control, use Corn Gluten Meal (CGM).  This is simply a byproduct of the milling process of wet-milled corn, so it is completely natural and considered very safe.  Just don't confuse it with cracked corn, which is not the same thing (we've seen it happen, and you wouldn't believe the birds and animals it will attract).  Corn Gluten Meal prevents crabgrass seeds from taking root as they sprout so it has a similar effect compared to chemical crabgrass controllers.  However, most people report that it takes a few seasons to get the full effect from this product.  Most sources report that you get about 60% control in the first year, 80% control in year 2, and almost 100% control of crabgrass in year 3 using CGM, but we confess that this will be our first year of using it.  Also, you will use more product by weight to cover the same area when using CGM.  It takes 20 - 25 pounds of CGM to cover 1,000 square feet of lawn, and using less than this seems to produce consistently poor results.  On the plus side, CGM helps to feed your lawn with nitrogen as it decomposes, so you get some slow-release fertilizer as an added benefit.

    Regardless of which option you choose, we can't over-emphasize the need to put down your controller when you see that forsythia start to bloom.  And remember, we don't offer lawn services, but we are happy to take care of almost any other home repair, maintenance and improvement job you have.  Go out and enjoy the fresh air and your lawn, and we'll handle those other tasks around the house.  That sounds like a great recipe to keep you from being crabby this spring!