I keep reading the weed triangle approach to weed control, and have used it with good success, but
Is there a dumbed down version for understanding which preemergent to use? The yard is coming along nicely and the last thing I want to see is a weed explosion.

I read alot about Barricade/prodiamine; but what about the others. Turf files says "Common preemergent herbicides labeled for use in turfgrass areas include benefin, dithiopyr, oxadiazon, oryzalin, pendimethalin, prodiamine, and trifluralin (these are common names and are often sold under various trade names). Although each of these products offers acceptable control, one should consider the herbicide mode of action. Most of these products, including benefin, oryzalin, prodiamine, pendimethalin, and trifluralin are members of the dinitroaniline (DNA) herbicide family."

Do most people here use Barricade because it's long lasting? Organic? Broadest spectrum of weeds? The Best?

I have never used a preemergent before mostly because my yard has never been so nice, so I've been reading and will keep reading, but thought I would ask the forum "why" they use what they use.

A really simple list, with the trade names. The big three are the ones you'll most often see:

Tupersan/Siduron: For use when seeding. Short coverage. Expensive. Not all that effective, really, but it helps.

Dimension (dithiopyr)/Many other trade names: Short to moderate coverage depending on usage. Has some post-emergent effect on very young crabgrass, so a slightly late application still works. Pretty easy to find and pretty inexpensive all things considered.

Barricade (prodiamine)/Guardrail/Many other trade names: Moderate to long coverage depending on usage, the longest of the commonly-available pre-emergents (up to 9 months or so). Moderately easy to find. Not for use if you're planning on seeding in fall as long-term coverage can cause that to fail.

Personally, I use Barricade for the long-term protection. Both Dimension and Barricade target slightly different plants, so it depends on what you get, but both are generally good.

Another thing to consider is the vehicle of transmission for these pre-emergent products. You can find products with Halts or Dimension at any big-box store, but it will be bundled with a high N fertilizer. The time to drop your pre-emergent (March/April) is not the time to be dropping synthetic N (Note: for a fall application, these products are fine).

Back to spring applications, the ones I use are Guardrail (prodiamine), which is spread via sprayer, and Dimension (Lesco sells a 0-0-7 granular with Dimension that is sometimes hard to fine. They'll try to sell you their more common 19-0-0. Greenlight also has a straight Dimension bagged product).

likeasponge wrote:Do most people here use Barricade because it's long lasting? Organic? Broadest spectrum of weeds? The Best?

I like barricade.

Long lasting, safe for use around trees, and the broadest spectrum of weed control for weeds I've seen in MY lawn.

I have seen some write ups on the effect of pre-emergents on root growth, particularly on previous fall seedings. I remember seeing some study results indicating, by pre-emergent, the root growth impact. Does anyone have any info on that? I lost a lot of my links/files when I had a recent computer crash.

how about scotts halts...i have a few bags.
Active Ingredients
1.71% Pendimethalin

Nothing wrong with Halts, if you already have it, use it! Is it straight Halts, or mixed with high nitrogen fertilizer? If mixed, I would not use it in early Spring due to the unwanted accelerated growth from the nitrogen- use something else and save it for a Fall application.

no, i have bags of regular halts...how long does it last, 30, 60 days?

For a fescue based lawn, I prefer Dimension over Barricade only because of its shorter protection time period. I would rather apply Dimension every 3 months starting in March, because that way if a overseeding project is required due to a unusually hot/dry summer or an imposed watering ban,you can successfully do it in late summer/early fall.....if you dropped a single app of Barricade in mid March, your protection level would inhibit successful overseeding right thru til late October/November,much too late for optimal results.

nclawnguy wrote:no, i have bags of regular halts...how long does it last, 30, 60 days?

read the instructions on the bag, as its length of coverage is based on the amount you decide to apply.

nclawnguy wrote:how about scotts halts...i have a few bags.
Active Ingredients
1.71% Pendimethalin

I have a few bags of Halts in my shed as well. Until I wandered onto the BL forum, I had no idea anything else even existed out there. Halts works, but only for crabgrass and a few other grassy weeds (they are listed on the bag - I think there are 6 weeds listed) and only for I think about 60 days (that's a stretch in my opinion). I didn't have many weeds in my fescue, so I'll probably use the Halts on that since I may want to throw down more seed next fall. The front yard where I have zoysia has had an explosion of chickweed and other pesky weeds in the thin/bare areas, so I think I'm going to try one of the other ones out front come March. I may go with Dimension because you can get it in granular form, but I'm still reading up on what's available. Prodiamine sounds great, but I think it comes in liquid form only. I don't trust myself with a hose end sprayer (never used one before) and it would take me a very long time with my 1 gallon tank sprayer.

xapabwa wrote: Prodiamine sounds great, but I think it comes in liquid form only.

It comes in granular form, too.

Stonewall at Lesco. There is also a Barricade Dg Pro.

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If Halts is good for 6 grassy weeds and provides coverage for about 30 to 60 days; would it be safe to say that spot spraying for "other" weeds would be required?

Barricade seems expensive, how long does a 3 lb bottle last typically? Though I like the fact it's safe around tree (we have a lot).

I like the thought of Dimension (dithiopyr) for it's shorter span, based on reseeding areas that the renew didn't come in to well.

It sounds like I need to monitor and watch to see what kind of weeds start to invade, most importantly putting "something" down without added Nitrogen.

Thanks for breaking it down so I can understand

Michael Wise wrote:

xapabwa wrote: Prodiamine sounds great, but I think it comes in liquid form only.

It comes in granular form, too.

Stonewall at Lesco. There is also a Barricade Dg Pro.

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Awesome! Thanks, Michael. I'll check out the granular options. I might be able to muster up enough courage to to use the liquid forms by spring, but it's always good to know there are options available.

flo

Any recommendations for dealing with Japanese stiltgrass/microstegium?

MattPete wrote:Any recommendations for dealing with Japanese stiltgrass/microstegium?

Have you tried maintaining a year round pre emergent barrier?

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This yard is relatively new to me (moved in a little over 2 years ago), so 'no'. Having said that, I did try Halts in mid-April last spring, and I had stiltgrass starting to sprout by June 1st. The only thing I found that could kill it post-emergent was Bayer Crabgrass killer (Acclaim Extra).

MattPete wrote:This yard is relatively new to me (moved in a little over 2 years ago), so 'no'. Having said that, I did try Halts in mid-April last spring, and I had stiltgrass starting to sprout by June 1st. The only thing I found that could kill it post-emergent was Bayer Crabgrass killer (Acclaim Extra).

I don't know all the ins and outs of pre emergent 1/2 life and all that, but Halts(pendimethaline) is suppose to be on of the shorter lived pre emergents. Halts definitely isn't a one and done in the spring pre emergent.

I'd give something like prodiamine(barricade, gaurdrail, stonewall) or dithiopyr(dimension) a try this year. Use a split app to give year round protection.

Timing is going to be everything. Do you know what soil temp it germinates? Is it similar to crabgrass in germination times?

Michael Wise wrote:
Timing is going to be everything. Do you know what soil temp it germinates? Is it similar to crabgrass in germination times?

Google is saying it germinates a few weeks BEFORE crabgrass. I don't know how that equates into soil temps. You just have to make sure to get it out before germination.

Too late, and the weed has already germinated. Too early, and you risk not having a strong pre emergent barrier around when the weed wants to germinate. The latter is less of an issue when using a long lasting pre emergent like prodiamine or dithiopyr.

[ Post made via iPhone ]

Here's a question.

The winter has been anything but. It is freezing cold now and for the next few days, but I'm reading long term outlooks and there is a increasing chance that the east coast may torch 60's/70's toward the end of January & February (remember this is based on weather models, not my opinion. Anything can change) for a substantial amount of time. If in fact this is true, would one be prudent to drop their Pre-M as the conditions warrant in February, even if it is six weeks earlier than normal or just stay the course. Problem with the earlier drop is that the efficacy will lessen during the heart of spring/early summer.