[Bacon117]

Hello Everyone: I'm trying to understand the application rates for my 30gal tow behind sprayer. As an example, I am looking at the concentration for Spectracide Weed Stop (dimethylamine salt) and it calls for 32oz of product with 32 gallons of water to treat 8,000 square feet. That works out to ~173 gallons per acre. :shock:

If I set my application rates (speed/ nozzle size, etc) to, say, 30 gallons/acre, but put in 32 oz. of product into my sprayer, I will get the same amount of active ingredient per acre, but just with less water.

So, I guess my question is, what are the side effects of applying chemicals to my lawn with less water than the directions call for? Will it simply not absorb into the soil as well? Should I simply select a chemical that can be applied at higher concentration percentages?

Thanks for any advice.

 

[Turfguy93]

It's more of a coverage issue, the more carrier the better coverage to an extent. Lots of products recommend 88 gallons per acre

 

[Bacon117]

But no matter how much carrier there is, i'm still applying the same amount of active ingredient, right?

 

[gene_stl]

Your logic is correct. But you should think about it for each different active ingredient. Sometimes in addition to amount of active ingredient per acre and the amount of carrier coverage you may need to think of the concentration of potent active ingredient per unit of volume. There may be ai s where they specify a particular amount of water for a good reason.

Right now here in St. Louis it is raining good. I am waiting to see whether the hot sulfentrazone solution I was spraying on Dallis grass killed or just bleached my northern mix. The sulfentrazone was there because I was also going after sedges.
The solution was too hot to use Grass Factor's terminology. I included spreader sticker which makes it hotter.

 

[Delmarva Keith]

Hello Everyone: I'm trying to understand the application rates for my 30gal tow behind sprayer. As an example, I am looking at the concentration for Spectracide Weed Stop (dimethylamine salt) and it calls for 32oz of product with 32 gallons of water to treat 8,000 square feet. That works out to ~173 gallons per acre. :shock:

If I set my application rates (speed/ nozzle size, etc) to, say, 30 gallons/acre, but put in 32 oz. of product into my sprayer, I will get the same amount of active ingredient per acre, but just with less water.

So, I guess my question is, what are the side effects of applying chemicals to my lawn with less water than the directions call for? Will it simply not absorb into the soil as well? Should I simply select a chemical that can be applied at higher concentration percentages?

Thanks for any advice.

Dimethalamine salt is the chemical form, not the active ingredient. Spectrocide weed stop is a typical 3-way post-emergent. They (almost certainly) specify that much water to ensure the weeds are actively growing and take up the herbicide. If the weeds are healthy and actively growing, just spray it like any other 3-way using volume of herbicide per acre of ground.

If I'm reading the label right, you need to apply 4 oz. per 1,000 sq ft. for your grass type. That is 174 oz. per acre. If you spray 30 gal of water to cover an acre, you would need to add 174 oz. of that product to the 30 gal. tank for the label rate. Remember that generally, the more water per acre, the better the coverage of the weed with chemical. 30 gal should be fine.

With a lawn the size of yours, you should get to know your local ag or landscape supply and buy pro strength chemicals. It will end up costing a lot less per app.

 

[g-man]

^ +1

Most product call for a 1gallon/ksqft carrier rate. Could you go lower? Sometimes. It depends on the risk to benefit. While the total amount of ai over the total area will be correct, the individual drops will be at a higher concentration. This presents a couple of risks: 1) there are a total of less drops (since there is less water), so some leafs might not get a drop, 2) the drops that do land on the leafs will have higher concentration. Herbicide on the weeds, not that big of a deal, but on the desired grass, it could cause some damage. I dont think the risk is worth it with herbicides application (foliar); PreM maybe (soil).

Using the using tractor supply / rural king /site one for your herbicides will save you some money at above one acre.

Im assuming this will be your first time using the 30 gallon tow behind. I would suggest you split the lawn in 2 areas and apply 30gallons to each. If you still want to use a single 30 gallon for the 1.3 acres, please do a practice run with just water to ensure you cover the entire area.