I think that pre emergences can work at any time, but do not kill what has already emerged. Around here people put Round Up over all their lawn. Since the Bermuda is obviously dormant, it will not hurt it, but will kill any weeds that are active. Then they put down pre emergence. Last year was my first year to use Preen, a pre emergence that can be used in rose beds. I say rose beds because I am not sure about its use in beds that expect the flowers to spread. Columbine always reseeds itself, so I wouldn't put it in with the Columbine.

Last year I did not do the Round Up thing or pre emergence and had weeds everywhere.

Thanks for the reminder.
Sammy

Yes! Of course you are right. Pre-emergents go out before weeds emerge. The problem in our wacky climate is that weeds emerge erratically--very early in some years and not as early in others.

The lawn care folks market more by "the calendar" than by what is really happening in people's lawns/gardens. Some (though certainly not all) are unscrupulous and will market products "out of season" just to sell the product, regardless of whether it will do anything for your lawn or garden at that point in time.

I garden 98% organically (I will use Round-Up on bermuda grass but that's about all), but before I gardened organically, I knew quite a lot about pre-emergents and post-emergents. You know, you have to understand how they work if you're going to use them, so you aren't at the mercy of the "marketing" people and ad campaigns.

Some gardening experts recommend that you apply pre-emergents at least 3 times a year: twice in the winter-spring time period, once in late winter to prevent those plants that emerge early/in cool weather and then later, in late spring, to prevent those plants that emerge in summer. The third application is usually recommended for early to mid-September to prevent the emergence of cool-season annual weeds (unless you are overseeding with rye or fescue and then you wouldn't use the pre-emergent).

Would it hurt to use a pre-emergent now that you see cool-season weeds already sprouting? I doubt it. Since they don't all sprout at the same time, using a pre-emergent now will probably stop anything that hasn't already sprouted.

If you decide to go ahead and use your pre-emergent after you've already seen the emergence of some weeds, please keep us all posted on whether you think it had any effect. That way, it will be a good learning experience for us all.

By the way, there's a company out of Ardmore that is marketing "Red River Crabbgrass" as grass that is "excellent grazing, hay and land cover". I saw their ad in the March/April 2005 issue of "Hobby Farm" magazine". Clever idea on their part--turning their crabgrass into a business (ha!) but WHO IN THE WORLD would deliberately buy crabgrass? They can come to our place and dig up all they want for free!

I like to put down Pendulum, Trimec 992, and Roundup mixed with a surfactant about this time of year. Wish I could afford to do the whole yard, but 4 acres can get a little expensive. We try to do most of the yard close to the house and greenhouse.

randy

Wow!
You folks sure do know a lot about lawns and weeds!
I have used Roundup before to kill out the crabgrass but ended up killing out the bermuda as well. I guess I'll check to see if any bermuda at all is greening up and try that followed by the Scotts in the shed.
I really hate the whole weed, feed, kill bugs, mow and so on of lawn care. Would just as soon get rid of the entire lawn and have nothing but sensible zone 4 plants and gravel and such. It takes a grand total of 20 minutes ot mow the front but about an hour to mow the back.

However, DH likes to gaze out across the verant savannah of our urban lot, watching no doubt for marauding predators such as the fierce cave bear, as he grills wooly mammoth over smouldering charcoal briquets. Gotta love him!

i would be very surprised if you had crabgrass right now, it is one that will start germinating at the same time that the forsythia starts to bloom.

I am a bermuda grass hater. I have to agree with OKC1 that my idea of a yard would be no grass, other than a teeny section to run barefoot through now and again. I would have the shrubs, a couple of flower beds, the veggie garden......and my fruit trees of course!

~Heidi (who hates, hates, hates bermuda grass)

I have a nice crabgrass infestation... Alas. I am in the process of planting columbines and with each shovel of dirt dug, I have to seperate out the crabrass. Needless to say this is a pain in the BACK...too.
I did spray twice with Roundup but when I dig out the plant I can see fresh growth on the root system.
Any ideas? Its killing me!!!!!!!!!!!

Hey, I'm the wrong person to ask. The pre and post emergent I put down hasn't put a dent in our lovely crop of crabgrass. I think it takes straight Halts in January, which we've done before, to kill those tough roots. I've been yanking up the stuff, roots and all, but some of that stuff is really stubborn.

For post-emergent control of crabgrass and other summer annual grassy weeds, you can apply post-emergent herbicides in May or June when the grassy weeds are young and actively growing. (These products work best when applied during the time that daytime temps are in the 80s and 90s.) At lower temps, the uptake of the chemical into the grass is lower and thus may not work. At higher temps, your lawn grass can be damaged. Keep in mind that the post-emergent herbicides for grasses are arsenticals (arsenic-based). Some of the commonly sold ones are MSMA and DSMA, and some are sold with the word 'crabgrass' in their names, like Crabgrass Killer. Check the label directions, though, to be sure the arsenical is safe for your lawn grass. I know the arsenicals can be used on Bermuda, but not sure about other lawn grasses. Remember that the chemical herbicides must be absorbed through the foliage, so don't use them immediately after mowing when the foliage is short. And, they must remain on the foliage for 24 to 48 hours following application, so don't mow during that time frame either.

To prevent the same problem with crabgrass next year, keep in mind that winter annual weeds actually BEGIN to germinate in late August to early September (they stay so small you often don't notice them then) if there is enough moisture in the soil at that time. So, to prevent that germination, you can apply a pre-emergent about two weeks prior to the expected germination time.

And, if you are trying to maintain your lawn organically, corn gluten meal is the best product available for weed control as a pre-emergent.

Hope this info helps!

Dawn

The notion of corn gluten meal is a great idea...I guess for next year?

Anyway, I've tried about everything and nothing halts the late winter weeds, it simply slows them down. I finally sigh heavily and inform Mrs. Oklahawg that I'll be beefing about a sore back for the next two days, and then head out to pull them by hand. Blech.

Oklahawg,

You know...at this time of the year, if it's not one thing, it's another!!!!

Happy hand pulling and don't hurt your back too much!

Dawn