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Organically speaking....what to do with a weed outbreak?

Posted by rutgers1 6NJ (My Page) on
Sat, Apr 12, 08 at 11:11

I am transitioning to organics, but the main thing that keeps me dabbling in the synthetics is a weed that I think is spurge. It took over at points last year and it appears to rearing its ugly head all over again this year. The grass has yet to start growing to crowd it out, yet I see these little white flowers popping up all around. Last year, it found a way to exist no matter what I did (spot spray, mow high, water infrequently). I spent half of my summer pulling it out, only to find it return shortly thereafter.

I worked really hard last year to build up the soil, and I have gotten off on the right foot this year, but part of me wants to round up the entire lawn in the fall - zapping anything that grows for weeks prior to reseeding - hoping that I can finally kill off every last remnant of this weed.

I think part of the problem is that I have rye/fescue/kbg mix lawn that tends to grow in bunches and leave some bare spots here and there, thus opening it up to this weed. However, even in the absence of a bare spot, it seems to creep in.

Any ideas?


Follow-Up Postings:

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RE: Organically speaking....what to do with a weed outbreak?

If you increase the percentage of KBG in your lawn, you won't have as many problems with bunching. Spurge is easy to pull, but it wouldn't be so easy to pull with a weed hound, so you'd need to get down on hands and knees. If you pull it when you see it and let the grass grow thick and fairly tall, you'll see it diminish over time.


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RE: Organically speaking....what to do with a weed outbreak?

Spurge must be pulled by hand. If the soil is at all moist, it pulls easily with its weak root system. Keep after it and you will get it all. Then the watering and mowing will keep it out.


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RE: Organically speaking....what to do with a weed outbreak?

Hate to say it but sometimes I think it is best to break the cycle and use synthetic pre-emergents from spring through fall. In the past, I have found spurge difficult to pull in it's entirety and it can go to seed relatively quickly, insuring a new crop next year. It produces ungodly amounts of seed. Since you have not yet committed to organics, might I suggest a full year of pre-emergent coverage and killing off as many perennial weeds as possible with 2,4-D...and then going organic. Of course, if your weed problem is not that bad, this would be overkill. For me, a year of spring-summer pre-emergent coverage resulted in never having seen spurge again.


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RE: Organically speaking....what to do with a weed outbreak?

Yes to all of the above and I'll add....

Fire!! If weed issues are keeping you from making the jump get yourself a flamer. You don't have to drop money on something from Rittenhouse, you can just get a little
plumbers torch from a hardware store that only uses smaller propane cannisters. There are lots of models out there, some that don't have exposed flame at all but use a heating element instead for greater safety. I wouldn't use a flamer in every situation but in the right spot there is no better tool imo.


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RE: Organically speaking....what to do with a weed outbreak?

Thank you for the suggestions. Today I mowed a bit low with the bag on to catch all of the flowers that keep popping up wherever this weed (which I think is spurge) is. Normally I mulch mow, but today I wanted to decapitate the weeds. I think that my amended "hybrid" approach this year will be:
1) organic feedings...which I have been doing since last year
2) preemergent....which I didn't do last year and paid the price for it
3) spot spraying
4) no weed-n-feed or large scale spraying

But I think I am going to wait it out a wee bit longer before deciding on any spraying at all. I think I will let the grass grow high, spend one day pulling the spurge, put down a bit extra preemergent, and then hope, hope, hope that nothing grows back.

My big decision will take place in the fall. I really want to renovate with an elite kbg, but I don't know if my wife will let me. Plus, I can't stomach the thought of spraying Roundup all over the lawn. The only thing that makes spraying the Roundup palatable is that a healthier stand of an elite kbg will be a better guard against weeds and will, therefore, require less spot spraying.


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RE: Organically speaking....what to do with a weed outbreak?

The more you use the organic and cultural practices, consistently, the less you will need to weed.

I got to a point where the only thing I even needed to think about using pre-m for was poa annua. But, frankly, the amount of success I had with using pre-m on it caused me to just quit using chemical pre-m. My trees had done so well I had to switch off from any idea of one elite KBG monoculture anyway to several varieties of cool season grasses that might do better in the shade and then KBG in the areas still getting sun.

I just carry a small weed spade when I mow and get rid of anything that sticks out. After the first couple of mows in the spring, that might mean stopping two or three times a mow to none later on.


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RE: Organically speaking....what to do with a weed outbreak?

You need to understand that weeds thrive in the soil where nitrate level is high. When you have right set of organism in the soil and spraying molasses will help suck up excess nitrate in the soil making it harder for weeds to thrive.

This reminds me. I need to apply molasses that I was supposed to do 6 weeks ago!


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RE: Organically speaking....what to do with a weed outbreak?

Lou,

Can you add an explanation/how to - for this?

"spraying molasses will help suck up excess nitrate in the soil making it harder for weeds to thrive."


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RE: Organically speaking....what to do with a weed outbreak?

"spraying molasses will help suck up excess nitrate in the soil making it harder for weeds to thrive."

Molasses is sugar (plus crud), very high in carbon and with negligible nitrogen. Bacteria, with nitrogen ratios themselves of 4:1 to 9:1, suck up the sugars and burn them for energy, plus use that to reproduce.

For every 4 to 9 atoms of carbon incorporated into their structure, 1 atom of nitrogen has to be incorporated to hold the balance.

Bacteria have variable lifespans, but upon death they tend to burst, releasing the resources for either plant absorption or consumption by another bacteria.

Other critters eat the bacteria, but have higher ratios, releasing the nitrogen back into the environment. That cycles it back into the soil for either bacteria or your plants.

Eventually any nitrogen you drop will cycle in regardless of what you do, but this gives it some time to attenuate a bit. Some goes to outgassing (as nitrogen gas or nitrous oxide), some washes out, and so on.


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