In the past I have used a halts pre emergent. I did not have very good luck. Is this necessary in an organic program? Anyone out there on an organic program that does not use a pre emergent or CGM as a pre emergent? Will I regret it if I skip it. There are just so few options readily available and for the results I've gotten in the past, I can't justify the money. Thanks.

Erik

What are you trying to prevent? When did you apply the Halts? Halts has a shorter protection period than Prodiamine or Dimension, and I think costs more per sq. ft. too. Also, it does not have a post-emergent effect, and no pre emergent will be able to control weeds that germinated in the fall (if dropped in the Spring).

St Augustine, when watered only once a week and mowed at the highest setting, will have very few weeds. What weeds are we talking about? Post a picture if you don't know the weed types.

Crabgrass is what I am trying to control. There are a few areas where the st Augustine is a little thin and I'm trying to keep it away so the st Augustine will be able to spread. I did not apply the halts in fall only spring. It was feb 15 this particular year. I was watching soil temps in my area and applied accordingly.

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I am learning more about how to make St Aug spread and become dense. Here are the factors: water, mowing height, and fertilizer. I am convinced that more fertilizer is better as is more water. I am not as convinced that lowering the mowing height will help it spread.

I believe you are already watering 2x per week. Keep doing that and fertilize at least monthly, heavily, with some serious organic fertilizer (not just used coffee grounds). I have been using CGM monthly at 20 pounds per 1,000 square feet and my lawn has never looked better. After you see it getting more dense, then bring the mowing height back up. When the grass is dense and tall, you will not need to worry about crabgrass.

Dchall, Am I understanding this correctly? Watering 2x/week is best for getting the grass to spread. 1x/week is best for root depth and weed prevention. So I should water 1x/week in my mature established areas of the lawn and 2x/week in the areas where the lawn is thin? I have started fertilizing with Milorganite(easily available for a great price). Thanks.

Erik

2x per week is not what I'm saying. It might be every 5 days instead of every 7 days. Moisture seems to be key, though. When you let it go too dry, you definitely lose ground on the spreading.