When you think about lawn care, what comes to mind? One subject that likely popped into your head is weed control. Nobody wants to have a lawn full of weeds, so how can you prevent weeds from growing?
Whether you’re a devout lawn manager or a weekend warrior, you’re likely to engage in warfare against weeds at some point. Perhaps you can think of certain weeds that seem to rear their ugly heads year after year. This can be a royal pain in the you-know-what, but are those weeds in your lawn trying to tell you something? While they’re definitely not complimenting you on that new hairdo, they may be trying to tell you something much more beneficial.
Certain weeds can offer you a wealth of information about the flaws in your lawn management plan and insight into the health of your soil. And although ignorance is bliss, knowledge is also power. In this case, knowledge is in the form of advice given to you from the specific weeds growing in your yard.
What causes weeds in the lawn?
Chronic problems like under or over-fertilization, nutrient deficiency, too much or too little water, mowing at the wrong height or too infrequently, skewed soil pH, and too much shade can all be exposed if certain kinds of weeds seem to always be a problem in your yard. But it is important to also remember that just because you see these weeds in your lawn, doesn’t mean that you’re doing something wrong, but it’s worth a deeper look at your lawn care practices to see if there is an underlying issue causing their growth. You may also notice that you see the same weeds listed as indicators for different conditions. It’s typical for weeds to take advantage of more than one form of lawncare malpractice.
Naturally preventing weeds
Your lawn has a specific set of conditions that it would like to you provide, in order for it to perform its best. Performing its best includes choking out weeds and limiting their ability to establish in your lawn. When these conditions aren’t met, you may be giving the growth potential advantage to your lawn weeds simply by doing or refraining from doing certain things. Let’s take a look at some common operator errors and the weeds that may proliferate due to them.
Why Your Lawn Needs Fertilizer
Soils that lack overall nutrient content may have weeds such as clover (hop, red, white), lespedeza, plantain (buckhorn, broadleaf), timothy (timothy grass), and vetch (common, crown). A nitrogen deficiency may be the issue if you commonly see black medic, clover, and lespedeza. You may be putting out too much nitrogen if you commonly have problems with unwanted annual bluegrass, bentgrass bermudagrass, mallow (common), and purslane (common). Soils with excessive potassium may be dominated by dandelion. Try some Root Hume or Soil Hume to help increase your lawn’s soil nutrient availability.
Why Irrigation is Important
While there are some really drought-tolerant lawn grasses, the vast majority will require some form of supplemental irrigation at some point to get through the dog days of summer. If you’re one who is rather paranoid about inflicting drought stress on your lawn, maybe you’re guilty of overwatering. Additionally, maybe your lawn has very poor drainage and holds on to excess water. Too much moisture in the rootzone could be an issue if you commonly encounter annual bluegrass, barnyardgrass, bentgrass, chickweed (common, mouse-ear), crabgrass, goosegrass, ground ivy, kyllinga, moss, sedges, and speedwells. On the other end of the spectrum, if your lawn drains really quickly or you’re just not willing to run irrigation throughout the summer, dry soils are commonly inhabited by birdsfoot trefoil, black medic, field bindweed, plantain (buckhorn), sandbur, spurge, wild carrot, windmillgrass, yarrow, and yellow woodsorrel.
Soil Compaction Effects
If your lawn gets a lot of use and you’ve never aerified or it’s been a while since you’ve done an aerification, you may have compacted soil. Weeds that commonly grow in compacted soils include annual bluegrass, bermudagrass, chickweed (common, chickweed), goosegrass, knotweed, moss, puncturevine, speedwells, and spurge. If you are commonly battling any of the previously listed weeds, consider an application of Liquid Soil Loosener which can help relieve soil compaction.
The Importance of Soil pH
Depending on your location and the history of soil amendments that have been applied to your lawn, it’s possible that your soil pH could be out of the range required for a lawn growing vigorously enough to fend off weeds. The ideal pH range for turf is generally reported as 5.5 to 7. If your soil is below 5.5, meaning it’s on the acidic side you may see broomsedge, moss, and red sorrel. If your soil is basic or well above a pH of 7, you may be seeing a lot of plantain (broadleaf) or wild carrot.
How does Shade Effect Grass?
Shade is one of the most common issues in turfgrass management. Simply put, turfgrasses just need sun in order to thrive (well maybe not the fine fescues). Not only can too much shade negatively impact the growth of your lawn, but it can also give the following weeds an advantage over your turf. Annual bluegrass, Carolina geranium, chickweed (common), ground ivy, moss, nimblewill, pennywort, plantain (common), rough bluegrass, speedwells, star-of-Bethlehem, and yellow woodsorrel.
Mowing to Prevent Weeds
Properly mowing your lawn is one of the best things you can do to encourage a dense turf canopy capable of prohibiting weed germination and growth. All turfgrasses have a range of heights at which they should be mowed. Why is it bad to mow your lawn too short? If you’re consistently mowing below the recommended height, not only are you encouraging a shallow root system but you’re encouraging the growth of weeds like annual bluegrass, chickweed (common), crabgrass, and pearlwort. If you loathe the task of mowing your lawn and don’t get out there to mow as frequently as you should or you’re keeping your lawn tall, you may run into buckhorn plantain, chicory, common mullein, foxtails, hawkweed, johnsongrass, thistles, and wild carrot.
What should I do if I see weeds in my lawn? Remember as we said before, just because you see some of these weeds in your lawn, does not mean that you have issues with any of the aforementioned items. But if you notice that year after year, you can’t seem to get ahead in the battle against some of these weeds, take into consideration that there could be a problem, like the ones listed above, that is keeping your lawn from being at its competitive best.
Patton, A.J. 2019. Turfgrass Weed Control for Professionals. Purdue University Extension.
Jordan, J. 2018. Weeds as Indicators. Hot Topics. Clemson Cooperative Extension