Managing Weeds in Warm Season Lawns (2023)

Managing Weeds in Warm Season Lawns (1)

Annual trampweed (Fecelis retusa) is a winter annual weed that becomes established in lawns that are mowed very low and not irrigated or fertilized adequately. The fluffy seeds will blow in the wind. For more information, see HGIC 2319, Annual Trampweed.
Joey Williamson, ©2015 HGIC, Clemson Extension

Bermudagrass, centipedegrass, zoysiagrass, and St. Augustinegrass are the most popular warm-season turfgrasses grown in South Carolina. Warm-season refers to the fact that they prefer the warm temperatures of spring and summer to grow. In the winter months, they do not actively grow, but become dormant and the foliage turns tan.

Disadvantages of Weeds

The main reason homeowners want to rid their lawn of weeds is that they are aesthetically disruptive. In other words, weeds are ugly and interrupt an otherwise uniform appearing lawn. Additionally, weeds are fierce competitors that will strongly compete with the turf for sunlight, nutrients, and moisture. Lastly, weeds have a tendency to spread rapidly. A few left uncontrolled can quickly become a problem.

Managing Weeds in Warm Season Lawns (2)

Annual bluegrass (Poa annua) is a winter annual weed. Here it is producing white seed heads during late spring. Also mixed in the lawn is white clover.
Joey Williamson, ©2015 HGIC, Clemson Extension

Types of Weeds

Grassy vs. Broadleaf: Grassy weeds emerge from seed as a single leaf. The leaf blades are longer than they are wide and have parallel veins. Examples are crabgrass, dallisgrass, and annual bluegrass.

For more information, see HGIC 2325, Annual Bluegrass Control.

Broadleaf weeds emerge from seed with two leaves. Leaves have netlike veins, and many, like dandelion or white clover, have showy flowers.

Annual vs. Perennial: Annuals germinate, grow, and die within a twelve-month period. Summer annuals, such as goosegrass or crabgrass, germinate in the spring, grow through the summer, set seed, and die at the onset of cold weather. Winter annuals, such as chickweed, henbit, purple deadnettle, or annual bluegrass, germinate in the fall, grow through the winter, set seed, and die as temperatures rise in early summer

(Video) Prevent Weeds in Your Cool and Warm Season Lawn

Perennials grow for two or more years. They reproduce from vegetative parts such as tubers, bulbs, rhizomes, or stolons, though some also spread by seed. Perennials tend to be the most difficult to control. Examples are dallisgrass, wild garlic, nutsedge, white clover, and plantains.

Managing Weeds in Warm Season Lawns (3)

Purple deadnettle (Lamium purpureum), like its close relative, henbit (Lamium amplexicaule), is a winter annual weed, and appears in dormant lawns in early spring. For more information, see: HGIC 2321 Henbit.
Joey Williamson, ©2015 HGIC, Clemson Extension

Managing Weeds in Warm Season Lawns (4)

Dandelion (Taraxacum officinale) is a perennial lawn weed that spreads by wind-blown seeds.
Joey Williamson, ©2015 HGIC, Clemson Extension

(Video) Fall Weed Control Options in Warm Season Lawns

Proper Management

Weed control begins with proper management practices, which encourage a dense, healthy turf. Healthy turf shades the soil so that less sunlight reaches the weed seeds, which need light to germinate. A thick turf minimizes the space available for weeds to become established.

Best management practices include proper:

  • mowing height & frequency,
  • watering rate & frequency,
  • proper fertilizer analysis, rate, & timing,
  • liming as recommended by a soil test,
  • core aeration to reduce soil compaction,
  • and de-thatching as needed.

Depending on the type, each warm-season grass should be mowed at its recommended mowing height and frequently enough so that no more than ⅓ of the blade is removed. For turfgrass in partial shade, the mowing heights may be raised slightly. Mowing at the proper heights for the particular turfgrass will encourage a dense, healthy lawn. For more information on proper lawn mowing, please see: HGIC 1205, Mowing Lawns.

When lawns show signs of drought stress, apply enough irrigation to deeply moisten the entire root zone. Typically, water lawns with 1 inch of irrigation water per week if there is inadequate rainfall. One inch of irrigation water will moisten the soil down to 6 inches deep and encourage a healthy, extensive root system. During hot, dry periods and on sandy soil, irrigation may be required every three to five days. Watering more frequently (three or more times per week) will keep the soil surface excessively wet and will promote weed seed germination and growth. For more information on proper watering of lawns, please see HGIC 1207, Watering Lawns.

Fertilize and lime at the proper time and according to a soil test. Proper lime application will help to maintain a soil pH where nutrients are optimally available to the turf. For more information on proper lawn fertilization, please see HGIC 1201, Fertilizing Lawns.

Core aeration helps relieve the soil compaction that prevents optimum root growth and favors many weeds. Core aeration is superior to spike aeration and is best performed during May after the lawn has fully greened and is actively growing. For more information about lawn aeration, please see HGIC 1200, Aerating Lawns.

De-thatching removes the layers of dead roots and stolons between the soil surface and the living, growing grass. Improper fertilization and irrigation practices may increase the thatch layer, which, if greater than ½-inch thick, needs to be removed for best turfgrass growth. De-thatching is best performed in May once the turfgrass is actively growing. For more information about de-thatching a lawn, please see HGIC 2360, Controlling Thatch in Lawns.

Control with Herbicides

Even when all cultural practices are employed, weeds may still appear. If the number of weeds reaches an unacceptable level and pulling by hand is out of the question, one may need to apply herbicides. At this point, it is important to know what weed you are trying to control. Local Extension offices, the Clemson Home & Garden Information Center, the Clemson Plant & Pest Diagnostic Clinic, and state Extension publications can aid in identification.

Preemergence Herbicides: Preemergence herbicides are applied to the soil prior to weed seed germination. They provide good control of many annual grassy weeds and are the best weapon against crabgrass and annual bluegrass. They also control some annual broadleaf weeds. Most are in a granular formulation, but some are applied as a liquid spray.

Most granular and liquid preemergence herbicides should be watered into the soil with about ½ inch of irrigation immediately following application. This activates the herbicide, which is absorbed by the young roots of weeds as they begin to grow.

In the spring, preemergence herbicides should be applied when air temperatures reach 65-70° F for four consecutive days. On average, this is March 1 for the coastal and central regions and March 15 to 30 for the piedmont and mountains. In the fall, to control winter annuals, apply preemergence herbicides when nighttime lows reach 55 to 60° F for four consecutive days. On average, this is September 15 thru October 1 for the coastal and central regions and September 1 to 15 for the piedmont and mountains.

Preemergence herbicides are generally effective for six to 12 weeks, depending on the product. For season-long control, make a second application eight or nine weeks after the first. See Table 1 for examples of herbicides and products.

(Video) Killing Weeds in Warm-Season Lawns | Celsius WG | Chamberbitter, Spurge, Doveweed, Dandelion, & More

Postemergence Herbicides: Postemergence herbicides target visible weeds. They are used primarily against broadleaf weeds, perennial grasses, and sedges. The chemicals 2,4-D, dicamba, mecoprop (MCPP), carfentrazone, and sulfentrazone are very common broadleaf herbicides for use in warm-season turfgrass lawns. They have been combined in many products that control most broadleaf weeds. Often products will contain one or more of these broadleaf herbicides mixed with additional herbicides for control of grass weeds and/or sedges.

Bentazon, imazaquin, and halosulfuron are sedge killers. Sethoxydim, quinclorac, fluazifop, and fenoxaprop are selective grass weed killers. Sulfentrazone and carfentrazone kill broadleaf weeds and sedges. MCPA controls a wide range of broadleaf weeds but is less commonly found in lawn herbicide mixes. Atrazine is both a broadleaf weed and grass weed killer.

Most of these postemergence herbicides can only be used on certain species of turfgrass. Read the product label to be sure it can be used safely on the type of turfgrass in the lawn. See Table 2 for examples of herbicides and products.

Guidelines for Using Postemergence Herbicides

When choosing an herbicide, be sure that it will control the targeted weed and that it is recommended for the specific turfgrass in the lawn. Before using, read the entire label and follow it precisely for rate and timing.

The following tips will help you achieve optimum control.

  • Most broadleaf weeds are best treated in the spring or fall when air temperatures are between 65 and 85° F. During hotter temperatures, turf damage is more likely to occur.
  • At the time of treatment, soil moisture should be adequate. When stressed by drought, weed control is poor and turf damage may occur.
  • Do not mow immediately prior to or after application. Mowing lessens the amount of herbicide that contacts weed leaf surface area.
  • Treat weeds when no rain is expected for at least 24 hours with spray applications.
  • Avoid treating on windy days because herbicide drift can injure ornamental plants.
  • Best results occur when weeds are young.
  • For acceptable control, repeat applications may be required. The product label will tell when to retreat the weeds.

Precautions for New Lawns

It is best not to apply any herbicides during the first year after seeding or sodding a lawn. Besides, during this first year, there may be no weeds that need controlling. Simply mow and bag the clippings for any minor weed problems.

However, if weeds have become significant, postemergence herbicides can be applied to newly seeded lawns at ½ the rate, but only after the lawn has been mowed four times. If the lawn is to be over-seeded after postemergence herbicide treatment, wait three to four weeks to reduce injury to the new seedlings, depending on the product. If seeding after applying a preemergence herbicide, wait at least nine weeks but read the product label for the exact amount of time to wait after application before seeding.

In recently sodded areas, preemergence herbicides can be applied following signs of new growth, at ½ the rate recommended for established grasses. Postemergence herbicides should not be applied until the turfgrass is visibly growing and spreading. Use ½ the recommended rate until after the turf has been mowed three times. For most postemergence herbicide products do not make applications to established warm-season lawns during the spring green-up period. Wait until the lawn is fully greened before treating.


February – March:

Preemergence: Apply a preemergence herbicide (see Table 1) according to the previously mentioned dates. If rain is not expected within 48 hours, apply ½-inch of irrigation. Many preemergence herbicides do not last more than 8 or 9 weeks, so a second application may be required 60 days later.

Postemergence: Before turfgrasses begin to green up for summer growth, apply a postemergence herbicide (see Table 2) to control winter broadleaf weeds or summer broadleaf weeds that have emerged. Turf damage may occur following some broadleaf herbicide applications if used during turfgrass green-up, especially in more sensitive turfgrasses, such as centipedegrass and St Augustinegrass. If the lawn has begun to come out of dormancy, then wait until the turfgrass is totally greened up before applying a postemergence weed killer. As with any pesticide, read the label to make sure that it is appropriate for your situation, and that it is being applied at the correct rate.

May – July:

(Video) Warm Season Grasses: A Lawn Care Guide

Preemergence: If making two spring applications, apply again 60 days following the first application

Postemergence: If annual grasses such as crabgrass, or perennial grasses such as dallisgrass have emerged, apply a postemergence grass herbicide. Two to three applications 14 to 21 days apart may be necessary for control. For broadleaf weeds, apply a three-way mixture, such as products containing 2,4-D, dicamba, and mecoprop. See Table 2 for examples.

August – October:

Preemergence: Make applications according to the previously mentioned schedule to control annual winter weeds. Most crabgrass preventers will stop most annual grass weeds from coming up in the lawn, including annual bluegrass (Poa annua). However, these preemergence herbicides may need to be reapplied again in the fall for season-long control, so check the product label (see Table 1).

Postemergence: Continue to treat grassy and broadleaf weeds. Best control is achieved when treating young plants. Typically, spray when temperatures are below 90 °F to reduce injury to the lawn. Be sure the lawn is not under drought stress.

November – January:

Postemergence: Treat winter broadleaf weeds with a postemergence herbicide on mild days. Wild onions and garlic are best treated during November and again during February using a three-way herbicide. If necessary, repeat spray application during the following November (see Table 2).

Non-selective herbicides, such as Roundup or Eraser, can be used safely on bermudagrass that is completely dormant. However, in SC, turfgrasses may not go completely dormant due to the mild winter, and glyphosate application may delay turfgrass green-up in the spots where sprayed.

Table 1. Preemergence Herbicides for Lawns.

TurfgrassWeeds PreventedActive IngredientsExamples of Brands & Products
Bermudagrass Centipedegrass
St. Augustinegrass Zoysiagrass
Annual grass weeds including crabgrass & annual bluegrass; also some broadleaf weedsbenefinPennington Crabgrass Preventer
Same as for benefin, plus goosegrassoryzalinSouthern Ag Surflan A.S.
Same as abovebenefin + oryzalinHelena XL2G
UPI Surflan XL2G
Green Light Amaze Grass & Weed Preventer
Summer annual grasses, annual bluegrass, some selected annual broadleaf weedsbenefin + trifluralinAnderson Turf Products Crabgrass Preventer with 2% Team Herbicide
Hi-Yield Crabgrass Control
Same as for benefin, plus oxalis & speedwell, goosegrass, sandbur, henbit, purslane, spurge, hopcloverpendimethalinScotts Halts Crabgrass & Grassy Weed Preventer
Same as for benefin, plus oxalis, lespedeza, bittercress, chickweed, henbit, & parsley-piertdithiopyrBonide Crabgrass & Weed Preventer for Lawns & Ornamental Beds
Hi Yield Turf & Ornamental Weed & Grass Stopper Containing Dimension
StaGreen CrabEx Crabgrass & Weed Preventer
broadleaf weeds, such as chickweed, clover, henbit, bittercress, spurge, plantain, & othersisoxabenFerti-lome Broadleaf Weed Control with Gallery
St. Augustinegrass
summer annual grasses, annual bluegrass, some selected weeds such as chickweed, spurge, goosegrass, henbit, crabgrassprodiamineHarrell’s with Barricade
Helena Pro-Mate Barracade & Fertilizer 0-0-7
Howard Johnson Crabgrass Control with Prodiamine & 0-0-7
Lebanon Pro Fertilizer (0-0-7) with Prodiamine
Lesco Barricade Plus Fertilizer (0-0-7)
Lesco Stonewall Plus Fertilizer (0-0-7)
Pro-Mate Barricade Plus Fertilizer (0-0-7)
Scotts Halts Pro 0-0-7 & Halts Pro
Southern States Pro-Turf 0-0-7 with Barricade
Notes: These preemergence herbicides should only be applied to well-established turfgrass lawns.

Typically, the optimum time for lawn fertilizer applications and pre-emergence herbicide applications do not coincide. However, the small amount of potash in the 0-0-7 blends is normally not a problem and may be useful on sandy soils with fall applications to improve cold weather hardiness of the lawn.

Table 2. Postemergence Herbicides for Warm-Season Lawns.

TurfgrassWeeds ControlledActive IngredientsExamples of Brands & Products
Centipedegrasscrabgrass, goosegrass & other annual grasses &
bahiagrass and
dallisgrass suppression
Arrest (Whitehall Institute)
Segment (BASF)
Arrest (Whitehall Institute)
Segment (BASF)
St. Augustinegrass
clover, lespedeza, spurge, oxalis, dollarweed, Florida betony & other broadleaf weeds, and crabgrass & annual grassesatrazineHi Yield Atrazine Weed Killer
Southern AG Atrazine St. Augustine Weed Killer
Zoysiagrass1annual & perennial grasses, such as crabgrass, foxtails, goosegrass,


bermudagrass suppression, quackgrass, torpedograss

fluazifopGordon’s Ornamec Over-The-Top Grass Herbicide
Gordon’s Ornamec 170 Grass Herbicide
Syngenta Fusilade II Turf & Ornamental2
St. Augustinegrass
wild garlic, wild onion, dandelion, clover, plantains, and most other broadleaf weeds2, 4-D + dicamba + mecoprop (MCPP)Bayer BioAdvanced Southern Weed Killer For Lawns Conc.; & RTS
Bonide Weed Beater Lawn Weed Killer with Trimec
Ferti-lome Weed Out Lawn Weed Killer with Trimec
Gordon’s Trimec Lawn Weed Killer Concentrate
Ortho Weed B-Gon Lawn Weed Killer Concentrate; & RTS
Ortho WeedClear Weed Killer for Lawns Concentrate
Southern Ag Lawn Weed Killer with Trimec Conc.
Spectracide Weed Stop Weed Killer for Lawns; & RTS
St. Augustinegrass
wild garlic, wild onion, dandelion, clover, plantains, and most other broadleaf weeds, plus sedges2,4-D + dicamba + mecoprop (MCPP) + sulfentrazoneGordon’s Trimec Nutsedge Plus Lawn Weed Killer Concentrate
Spectracide Weed Stop for Lawns Concentrate 2
St. Augustinegrass
wild garlic, wild onion, dandelion, clover, plantains, and most other broadleaf weeds; & moss suppression2,4-D + dicamba + mecoprop (MCPP) + carfentrazoneBonide Weed Beater Ultra Concentrate
Ferti-lome Weed Free Zone Concentrate; & RTS
Ortho WeedClear Lawn Weed Killer Concentrate 2 Concentrate; & RTS
Gordon’s Trimec Speed Lawn Weed Killer Concentrate; & RTS
crabgrass, foxtails, signalgrass; most broadleaf weeds, such as dollarweed, black medic, wild onion & garlic, speedwells, plantains, dandelion, white clover, violets, henbit, chickweed, star of Bethlehem2,4-D + dicamba + quincloracBonide Weed Beater Plus RTS
Bayer BioAdvanced All-in-One Lawn Weed & Crabgrass Killer Concentrate 1
Ferti-lome Weed Out with Crabgrass Killer Concentrate; & RTS
Monterey Crab-E-Rad Plus Concentrate; & RTS
Ortho Weed B Gon Max Plus Crabgrass Control Concentrate
Ortho WeedClear Kawn Weed Killer Concentrate; & RTS
Gordon’s Trimec Crabgrass Plus Lawn Weed Killer Concentrate; & RTS
crabgrass, foxtails, signalgrass; most broadleaf weeds, such as dollarweed, black medic, speedwells, plantains, dandelion, white clover, violets, henbit, chickweed, star of Bethlehem, & nutsedges.2,4-D +
dicamba +
quinclorac +
Spectracide Weed Stop for Lawns Plus Crabgrass Killer Concentrate
crabgrass, foxtails, signalgrass; some broadleaf weeds, such as dollarweed, black medic, speedwells, dandelion, white clover, violets, henbit, chickweed, star of Bethlehem, & nutsedges.sulfentrazone +
Image Kills Crabgrass Concentrate
many broadleaf weeds; partial bermudagrass suppressionMCPA +
dicamba +
Monterey Spurge Power Concentrate
Bonide Chickweed, Clover & Oxalis Killer Concentrate
St. Augustinegrass
yellow nutsedge, globe sedge, annual sedge, and many broadleaf weedsbentazonBASF Basagran T & O 4L
Lesco LescoGran Postemergence Herbicide
Southern Ag Basagran Sedge Control
St. Augustinegrass
yellow & purple nutsedge, annual sedges, common purslane, groundselhalosulfuronGowen SedgeHammer Plus2
Monterey Nutgrass Killer2
Hi-Yield Nutsedge & Horsetail Control2
Martin’s Nutgrass Eliminator
St. Augustinegrass1
purple nutsedge, annual sedges, sandspur, wild garlic, and some broadleaf weedsimazaquinImage Nutsedge Killer
St. Augustinegrass4
Many grass & broadleaf weeds, such as dallisgrass, sandspur, lawn burweed, henbit, dollarweed, annual lespedeza, Virginia buttonweed, violet, white clover, black medic, tall fescuethiencarbazone
Celsius WG Herbicide
Read the product label to be sure the herbicide is labelled for use on the specific turfgrass in the lawn!

Do not apply postemergence herbicides, except Celsius WG Herbicide, to lawns during the spring green-up of turfgrass.

RTS = Ready to Spray (a hose-end sprayer)

1Intermediate safety; use at reduced rates.

2These products require the addition of 2 teaspoons of a non-ionic surfactant (that is, a wetter-sticker agent to aid in weed control at 0.25% by volume) per gallon of water, such as Hi-Yield Spreader Sticker.

3Intermediate safety on bermudagrass. Do not treat weeds in bermudagrass if temperatures are above 85 degrees.

4 Spot treatments to St. Augustinegrass at temperatures above 90 degrees may cause temporary growth regulation.

Table 3. Preemergence & Postemergence Herbicide Combination Products for Warm-Season Lawns.

Turfgrass Weeds ControlledActive IngredientsExamples of Brands & Products
St. Augustinegrass
Preemergence: summer annual grasses (such as crabgrass & goosegrass), annual bluegrass, & some broadleaf weeds, such as chickweed & spurge.

Postemergence: most perennial & annual sedges, many broadleaf weeds, crabgrass, & some annual bluegrass control.

prodiamine (pre)
+ sulfentrazone (post)
Bonide Prozone Weed Beater Complete Granules
Bonide Sedge Ender Concentrate; & RTS
St. Augustinegrass,
Preemergence: broadleaf weeds, such as chickweed, clover, henbit, bittercress, spurge, plantain & others.

Postemergence: most broadleaf weeds.

isoxaben (pre) + (post) 2,4-D + dicamba + mecoprop (MCPP)Bayer Advanced Season LongWeed Control for Lawns
Note: These preemergence herbicides should only be applied to well-established turfgrass lawns.

1 Application to St. Augustine may cause temporary discoloration.

Pesticides are updated annually. Last updates were done on 7/22 by Barbara Smith.

(Video) How to Get Rid of Crabgrass & Clover in the Lawn - Weed Control Like a Pro

Originally published 06/04

If this document didn’t answer your questions, please contact HGIC at or 1-888-656-9988.


What is the best time to kill weeds in lawn? ›

For the most effective control, apply in early fall (September 15 - October 15) or in spring (late April - early June). Fall is preferred over spring due to greater penetration of the herbicide down into the roots and the reduced possibility of damage to flowers and other vegetation.

At what temperature can you spray weeds? ›

Ideal temperatures for applying most POST herbicides are between 65 and 85 F. Weeds may be killed slowly below 60 F. Some herbicides may injure crops if applied above 85 F.

How do I get rid of weeds in my lawn permanently? ›

Glyphosate is the most widely used weed killer in the world and is strong, safe & reliably eliminates most weeds in one application. Kills right down to the roots so they don't grow back in one spray. Kills 99% of garden weeds including tough ones like brambles & ivy.

Does scarifying remove weeds? ›

Regular scarifying can keep down annual weeds too as well as helping to reduce the perennial ones. Weeding your lawn is something you can do either with a weed killing chemical which you put on the lawn, or manually. If you've only got a few weeds then it's not a huge chore to manually remove them.

Does mowing often kill weeds? ›

Most noxious weeds grow low to the ground after long-term repeated mowing. In these cases, periodic control through herbicides can remove plants that have acclimated to frequent mowing. Mowing will not eradicate noxious weeds.

Should I dig weeds out of lawn? ›

Once weeds are in your turf, you need to remove them. There are two ways to remove them: dig them out; or kill them with a herbicide. There is nothing wrong with digging them out, and it is good exercise and environmentally safe.

How do you get rid of weeds in hot weather? ›

Wait a few days for things to cool off to protect your corn from weeds and added stress. Avoid spraying herbicides, if possible, when temperatures surpass 90 degrees. During a heat wave, weeds shut down and can't uptake herbicides. Using multiple sites of action is especially important during a heat wave.

When should you not spray weeds? ›

Herbicides should not be applied to lawns when the temperature exceeds 85 °F or when the lawn is under moisture stress (wilted). The surfactant found in most herbicides can cause severe injury if applied during these conditions.

Does Roundup work better in hot weather? ›

Applying translocated herbicides, including Roundup® brand herbicides, in hot, dry conditions can result in delayed or reduced weed control.

What kills weeds down to the root? ›

White Vinegar:

For it to work, you have to wait for the vinegar to sit in the weeds from your garden for a few days. The vinegar will kill the weed's roots.

Should I Dethatch before killing weeds? ›

In general, we would recommend killing the undesirable plants and clearing out the dead plant debris before dethatching and then reseeding the lawn. Dethatching will be easier and you will get better germination with your new seed when the ground is better prepared for it.

Why is my lawn full of weeds? ›

Cause. Lawn weeds establish because they survive close, regular mowing. They spread by seed or creeping stems, and are usually problematic where the grass is sparse.

What month should you scarify a lawn? ›

When is the best time to scarify a lawn? Light scarification or removing the thatch can be done in spring, around the month of April, when it's getting warmer. In spring the growth and recovery rate of your lawn, and all your plants, is the highest.

What happens if you don't remove weeds? ›

They Can House Pests

Weeds can also house pests, which can further kill your plants. Pests use weeds as a home and shelter, so if you have weeds, you'll likely have pests. If you're gardening, if you don't weed and let the plants sit over the winter, then come spring, you might have an infestation of pests.

Can you kill weeds while growing grass? ›

I wouldn't worry too much about the weeds for now because most of them can be killed later by herbicides that don't harm grass. These are called broad-leafed weed-killers for lawns. The problem is that young grass is sensitive to this kind of herbicide.

Is it better to keep your lawn short or long? ›

Mowing too short or scalping results in stress to the grass plant. Weak grass plants will take longer to recover. To maintain a 3-inch lawn, mow before the grass reaches 4.5 inches tall. Mowing too short can allow weed seeds to get more sun and increase the chance of germination.

Can a lawn full of weeds be saved? ›

Reseeding Could Be a Solution

If you see plenty of healthy grass among the weeds or large areas of good grass throughout the lawn, you can save the existing grass and fill in the rest by planting new seeds. That calls for applying a broad leaf herbicide, which kills the weeds without harming the grass.

Does mowing over weeds spread them? ›

Mowing weeds that have already begun to produce seeds can spread the weeds. However, mowing weeds early—before they have the chance to mature—prevents them from producing seeds. It can also be helpful to spray weeds with herbicide several days before mowing, in order to ensure the weed dies.

Can you treat lawn for weeds in summer? ›

Killing Lawn Weeds in Summer

If it's summertime when you realize that crabgrass and other weeds have taken a stronghold of your lawn—and you never applied pre-emergent products—then you should still attempt post-emergent treatment.

Can you spray your lawn for weeds in summer? ›

It is not recommended you apply an herbicide at all when temperatures exceed 85 degrees as the herbicide will damage your grass. It is best to wait until it gets cooler and apply a post-emergent herbicide to any weeds that are currently in your yard.

Should you spray weeds in summer? ›

Warm Season Lawns

There is a very common weed control that you can get pretty much anywhere that works very well in summer and has NO heat restrictions. However, I still recommend you be smart and spray in the evenings when temps fall below 90 also.

Is it better to spray for weeds in the morning or evening? ›

Research shows PPO herbicides more effective at midday. Summary: Some herbicides are more effective when applied at noon compared to early morning or late evening applications, new research indicates. Researchers say the results have long-term implications for weed management.

Is it better to spray weeds before or after rain? ›

Most pre-emergent products actually perform better when applied just before a rain. Adequate rainfall assists this type with absorption to reach full effectiveness. Overly heavy storms, however, could result in excessive herbicide run-off with little to no result.

Is it better to dig up weeds or spray them? ›

Hand-weeding is better for removing a handful of weeds. Spraying weeds is better for handling large weed infestations. Pulling weeds by hand will not make future weeds harder to remove. Sprayed weeds still have to be pulled out of the ground once they die fully.

Does adding dish soap to Roundup help? ›

Dish soap is used as a surfactant, both when washing dishes and applying herbicide to plants. While it might effectively remove grease and food from plates, dish soap probably should not be the “go-to” surfactant for herbicides.

At what temperature should you not spray Roundup? ›

Glyphosate relies on translocation within plants for good activity, and herbicide movement within plants is greatly slowed during cool periods. The general recommendation is to avoid glyphosate applications when evening temperatures fall below 40°F.

Can I mix vinegar with Roundup? ›

Probably not a good idea. Roundup is only slowly taken up through the leaves and is easily washed off. There is a steady trade in surfactants and oils that are supposed to increase its speed of uptake and give better results. Since vinegar is likely to scorch the leaf, IMHO it would slow down the uptake of Roundup.

What is the easiest way to get rid of overgrown weeds? ›

How to Deal with Overgrown Weeds
  1. Weeds next to a curb or driveway. Mow down the crabgrass seeds. Aerate or use a dethatching machine. Add compost. Add fertilizer. Spread the grass seed. ...
  2. Weeds in flower beds.
  3. Weeds in the garden. Spray the weeds. Deprive them of sunlight. Weed eat the area. Torch the weeds.
  4. Overgrown “jungle lawn”
17 Jun 2022

What is the best method for you in controlling weeds? ›

Herbicides are considered the most effective and time-efficient method of weed control. Some herbicides are formulated so as not to cause harm to the surrounding plants of the weed. Chemical control is an effective way of controlling weeds.

Why you should not dethatch your lawn? ›

A thin thatch layer, less than 1/2-inch thick, is beneficial to lawn health. 1 It acts as an organic mulch to help conserve soil moisture and protect against big fluctuations in soil temperatures. A thin thatch layer allows water, nutrients and air to penetrate into soil and reach waiting plant roots.

Does power raking get rid of weeds? ›

A power rake is an aggressive tool that, when used, will rip through the grass on your lawn. When you power rake and tear out the crown of your grass, not only does your grass die, but the weeds in your lawn also now have the chance to take over.

Is dethatching or aerating better? ›

Aeration helps loosen the soil and helps decompose the excessive thatch layer at a faster rate. Both services accomplish a similar goal, but lawn aeration does so without the possibility of damaging your lawn in the way that dethatching would.

Can I scarify my lawn in March? ›

Generally, March is still too early to scarify your lawn. If you have a build-up of debris and moss it can be tempting to consider this task, but it's best left until April when the grass has a better recovery rate.

Do you reseed after scarifying? ›

For areas of your garden that have become bare during the scarification process, then you should consider reseeding these areas of your lawn. This is relevant if you are scarifying your lawn in the spring. March to April is the ideal time to begin growing grass from seeds.

Can I scarify my lawn in April? ›

If you've not already done so, April is the ideal time to tackle scarification. Scarifying pulls moss and dead matter out of the base of your lawn. It lets the air flow around the plant and helps with drainage. Just like a good spring clean.

What month Should I spray weeds? ›

The best time to treat weeds is when they are actively growing. This means you should start spraying and treating in the spring, usually sometime in April. You'll have to maintain your weed-killing regiment into late September/early October.

Is it better to kill weeds in fall or spring? ›

Fall is a good time to think about weed control in your lawn and garden. In fact, fall is actually the best time to control some difficult weeds. Many yards and gardens this spring had winter annual weeds such as henbit, deadnettle and common chickweed.

Is it better to spray weeds morning or night? ›

Research shows PPO herbicides more effective at midday. Summary: Some herbicides are more effective when applied at noon compared to early morning or late evening applications, new research indicates. Researchers say the results have long-term implications for weed management.

Whats better spraying weeds at night or day? ›

University studies show crop weed herbicide applications made early in the morning when the winds not blowing typically gives much less control than that same application later in the day.

Can you spray weeds in hot weather? ›

Temperatures in the low 90s or above can hinder herbicide uptake. Wait a few days for things to cool off to protect your corn from weeds and added stress. Avoid spraying herbicides, if possible, when temperatures surpass 90 degrees.

Can I spray for weeds in March? ›

If you start too early in March, you might find yourself out spraying for weeds when the air temperature is 65 degrees but the soil temperature is still too cold for the weed killer to work just yet. You might consider waiting a few more weeks and let that soil temperature warm up a little more.

Do you have to spray for weeds every year? ›

Year-Round is a Great Strategy For Killing Weeds

Obviously, you can't just target spring weeds and expect a great looking lawn all year if you neglect taking care of summer or fall weeds. As weeds germinate and grow, you have to have a process to target them.

Is it better to pull weeds when the soil is wet or dry? ›

Weed when the soil is wet and soft. Pull weeds soon after watering your plants or a rain shower; when the soil is moist, the whole weed is more likely to come out by the roots. It's perfectly fine to put pulled weeds in your compost bin, where the naturally hot temperatures will destroy any seeds.

How many times a year should you spray your lawn for weeds? ›

The frequency with which you can apply Ortho weed killers is typically limited to two applications per year – a primary application followed by a second application shortly thereafter to eradicate any stragglers or persistent weeds.

Should I spray weeds in the sun? ›

Herbicides in general tend to work best in warm sunny conditions when weeds are actively growing and cycling nutrients into their growing points. In these conditions, weeds will take in herbicides most efficiently.

Should I pull weeds after I spray them? ›

One of the questions we often get asked is - "do you have to pull up dead weeds after spraying them?" The short answer is yes, but it's important that you pull the dead weeds up in a very specific way to ensure that they don't come back to haunt you the following year...

How often should weeds be sprayed? ›

It works so well; one application is usually all you need to kill a weed. And some weeds can take as long as three weeks to die. If it's still hanging in there in two weeks, give it another spray.

Is spray or granules better for weeds? ›

According to Purdue University Turfgrass Science, liquid sprays tend to be more successful than their granular counterparts, simply because the liquid formulation is sprayed across the weed's leaf surface and does not rely on additional moisture to stick to the leaf.


1. How to Control Weeds on Your Lawn
2. Webinar: Managing Broadleaf & Grassy Weeds in Warm-Season Turf
(Landscape Management TV)
3. Best Summer Weed Control for Lawns
(Lawn Care Nut - Just Lawn Tips)
4. How To Get Rid of Weeds In Your Lawn This Fall // Lawn Weed Prevention
(The Lawn Care Nut)
5. Kill Weeds and NOT Your Grass with this POTENT Combo
(Ron Henry)
6. Organic tips to control weeds and improve your lawn
(Gardening Australia)
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