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How do I get rid of crabgrass at this time of the year??

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Joined: 6/12/2008
Location: Alabama
Posts: 3
Posted: Jun/12/2008 5:30 PM PST

I planted a new lawn about a month and a half ago with Rebel Exeda Tall Fescue.. I seem to have as much or more weeds coming up than grass.. From pics I have seen on the internet, I think the main one might be smooth crabgrass.. I live in Birmingham, Alabama so at this time of the year what is the best way to get rid of it? I have about an acre so pulling them by hand would be impossible.. I also noticed that some of the dirt is turning green.. Does this mean too much water? I have attached 3 pics, 2 of the main weeds and 1 of the green dirt.. Any help or suggestions would be greatly appreciated.. Thanks!


Kate photos
Joined: 4/05/2006
Location: northeast Nebraska
Posts: 101
Posted: Jun/12/2008 7:16 PM PST

Yup, yup, you have crabgrass. The second one is the never ending RAG-weed. My nemesis, and the bane of all autumn allergy sufferers.

Up here in NE we buy a product called TRIMEC Nutsedge and Crabgrass killer. It works fairly well. But, be warned, the grass has to be old enough to withstand the herbicide. Read the label carefully.

The last photo of the "green" dirt, was this a shady spot? Areas that get a decent amount of shade will look like this. If not shade, then cut back on the water a bit.

Hope this helps! Kate
Joined: 6/12/2008
Location: Alabama
Posts: 3
Posted: Jun/12/2008 7:51 PM PST

So the TRIMEC Nutsedge and Crabgrass killer works on the crabgrass and the rag-weed? Does it matter what time of the year you use it? The green dirt seems to be in shady and sunny spots.. I will try cutting back on the water.. I really appreciate this info and any more that anyone wants to give.. Thank you!
felicia photos
Joined: 4/21/2008
Location: Statesboro Georgia
Posts: 139
Posted: Jun/13/2008 6:39 PM PST

The crabgrass and ragweed are terribly invasive. I suggest the treatment as Kate did. I hate to tell you, but they will probably return next year still. They are horrible, horrible nuisances. If you planted seed and not sod and the seed was not planted heavy enough, the weeds will really have their way in your lawn. The weeds are also loving all the water and will grow faster than your seed will. I see u are in Alabama so it is hot like me in Georgia. I still would not water every day, or even every other day until you figure out what to do about your weeds. Good luck!
Kate photos
Joined: 4/05/2006
Location: northeast Nebraska
Posts: 101
Posted: Jun/13/2008 7:29 PM PST

I sold grass seed and lawn treatment programs for years at a regional nursery, and my best advice always used to be to plant grass in the fall, (in our zone 4, anyway!) The annual grasses are winding down by then and the new grass won't have to compete with the weeds.

Since you already have the grass in place, you're going to have to deal with it. When the grass is mature enough, apply the selective herbicide at recommended intervals through the summer. The next step is to then over-seed the lawn again at the time best for your zone in the fall.

Hope this helps, Kate
txrose blog photos
Joined: 3/04/2007
Location: Van, Tx
Posts: 2650
Posted: Jun/13/2008 8:54 PM PST

Conditions that promote crabgrass: any bare or thin spot on the lawn stressed by drought, insects or disease are especially susceptible.

In the spring pull plants before they go to seed. Bag clippings to avoid spreading seeds. Prevent crabgrass by keeping your lawn thick and healthy: water , mow, and fertilize.
Use a preemergence herbicide labeled for crabgrass in mid January: in cool climates apply it in March. In summer use a postemergence herbicide labeled for crabgrass. Apply when plants are still small;the larger plants become the harder thay are to control.

Almost straight from the lawn book I have...which has helped me more than I tell you!
Joined: 6/12/2008
Location: Alabama
Posts: 3
Posted: Jun/16/2008 2:45 PM PST

Thank you all for your suggestions.. I appreciate the help and now I'm going to go out and play in my weeds...I mean lawn.. :-)
Joined: 8/23/2008
Location: New York
Posts: 1
Posted: Aug/23/2008 11:36 AM PST

Don't waste your money and health on pesticides for crabgrass. It is annual, it will die by itself...As for seeds- one acre of land at any given time has from 4 to 40 pounds of weed seeds anyway. Post -emergent treatment does not really work well! Crabgrass has a purpose in nature:its roots loosen the compacted soil, it protects soil from erosion in dry conditions. To get rid of it, do the following:
-have the soil test done: grasses prefer nearly neutral conditions- the soil test results will include, which amendments needed, for example lime or otherwise. Costs 10$
-Aerate the compacted soil with core aerators in spring or fall, when SOIL temperature at least 50 degrees- the best period for grass roots growth, do not do it in hot or cold soil temperature. Costs 60-80$ for 24 hours rent
-Over seed yearly after aeration in fall with PREMIUM Brand Name, not Walmart or Home Depot seeds for your condition: shade or sun, heavy traffick or light. Check the test date on the bag of seeds , it is only good 6-9 month after the test date!!! Quality seeds will need diligent watering over 5-6 weeks, do not water every day, water 1-2 inch of water once a week or half that, twice a week.
Try not to save money on seeds, they are cheaper, than pesticides.
- if possible, top dress grass with 1/4 inch aged compost in early spring or fall, when soil is 50 degrees. In a couple of days, you won't see a mess and have a luxurious grass.
-Water less frequent, but DEEP. It will help to grow deep roots, which in turn demand less water in hot weather and help to keep the lawn green.
-Mow 3 and a half to up to 4 inches high. Taller grass grows 3-4 times deeper roots, than 1 and a half to 2 inch grass. Grass blades will shade all broadleaf and crabgrass seeds from germinating or suppress the one, which germinated
-Leave the clippings, when mow- it returns nutrients back into the soil.
-In drought conditions, do not waste water, let your lawn go dormant(brown)
You do not have to do aeration every year, unless your mowing equipment is heavy and compacts soil.Overseeding and mowing height is the most important to follow!
dimona photos
Joined: 1/28/2005
Location: Southwest Missouri
Posts: 162
Posted: Aug/23/2008 7:23 PM PST

SWEET!!! I have been asking this question for years as we are inundated with crabgrass!!! This year I heard Paul James say basically the same thing. Water deeply fertilize well and overseed. Seems to me a whole lot better than spreading a chemical that my chickens will eat up & die a horribly agonizing death! Diazanon is NOT there friends.
Joined: 8/25/2010
Location: new jersey
Posts: 8
Posted: Aug/25/2010 8:26 PM PST

crabgrass being useful is a far fetch. But all the suggestions will work.

the "green" in your photo is either light moss or fungus. usually found in more shady and overly wet sections, it CAN get into other areas weakened by drought and then watered too heavily and then left with poor drainage. I would bet you also have "brown spot" in there too...

if you are going to use chemicals, only use them DIRECTLY on the crabgrass, getting as many of the branches as possible. Be sure to follow the instructions whether they need to dry OR they need to be watered to work in. They generally will work best if they are allowed to work into the pores of the plant rather than dry onto the leaves... while mostly designed to work as labeled for the intended plant, they will kill almost anything they touch or at least give it a bad hangover.

crabgrass can be annual, semi-annual, or perennial, depending on conditions. This summer 2010 in the northeast has woken up every dormant seed possible especially crab and sedge. Both have to be treated as the separate plants they are.

But as for seeding, if the lawn is young and hasnt established or is weakened by drought, disease or even OVER watering, weeds win. If you maintain early pre-emergence treatments you stand a better chance with crab. Once its gotten to seed, it can seed 5 or 6 times a season with large amount of seed.

But once the heat has broken in your area, its time to get to work on them again. Its actually ambient temperature, or more correctly the GROUND temperature that controls growth. Grass stops growing in summertime for the most part about 85 degrees and weeds START, the reverse is true in fall, and thats when you can again overseed, aerate (mature lawns), and fertilize to prepare the lawn for winter dormancy.

What happened this year, was a lot of late snowfall, brief spring with a jump into the 90s (40+ days in new jersey) which cut into grass growth and gave weeds a jumpstart, with little rain in july and august its just been never ending.

now usually, we would be ending weed control, and preparing to aerate/seed. We are doing both and getting many many questions as to why...

(yes i work for a big lawn service company) but on my own lawn I avoid chemicals as much as possible, but this year is a Kill Em All mode.

watering remains the greatest asset for a lawn. Done right it brings the best results with or without treatments.

When you are watering, you arent actually watering the green bits, you are watering the ROOTS below ground, which is why people say "water 1 inch a week" but never explain WHY... you want to get the ground at root level or below to be where the plants feed from (this is also true with flowers) rather than on the surface. Water so that your soil on top is moist and that on days you dont water, you can still put your finger to the first joint into the ground with just a little bit of effort and it doesnt break up the soil, too much and your finger comes up noticebly wet. (if your feet make a squelchy noise, WAAAAY too much) too little and you hurt your finger... the soil should be dark, not sandy.

always water in morning, before sunrise and let the sun do the dry cycle. if you water at night, with humid conditions, the evaporation and dew point will just leave the grass like wet clothes sitting in the hamper. Mold and fungus.

(cripes i didnt mean to write such a long post) and a first one at that.

in any case, i hope my ramblings make sense...
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