Prodiamine question on app rates

Kentucky bluegrass, Fescue, Rye and Bent, etc
Post Reply
kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Prodiamine question on app rates

Post by kentster » August 20th, 2018, 7:22 pm

I am trying to make sure I understand the label instructions. My goal is to do two applications, one now and one in the spring, for Poa Annual and Crabgrass control.

I read that the application rate is 0.185-0.55oz per K, but I'm unsure how to select a value in this range. I figured it was grass type specific, but not sure. Since I'm inpatient, I guessed and applied today at 0.3oz/k (I think anyhow). I calculated that .3 oz/k x 7,500k = 2.25 oz. = 4.5 tablespoons. I just noticed that the label, however, shows that the 0.37 oz/k is equivalent to 1 tablespoon/k which would be a much larger 7.5 tablespoons for my 7,500 example.

My questions are: Is this rate about right for my KBG mix yard for 2 apps? what is the correct amount for this rate and area? ...and, if I got it wrong on the low side, should I apply again in 3 months?

Thanks guys!
Kent

seiyafan
Posts: 1745
Joined: August 9th, 2015, 7:08 pm
Location: Orange County, NY
Grass Type: Bewitched mono and TTTF/KBG mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by seiyafan » August 20th, 2018, 8:54 pm

for KGB, annual limit is 0.55oz /k, so 2 apps at 0.3oz each will put you a little over the limit.

gardenpants
Posts: 140
Joined: September 15th, 2016, 5:16 pm
Location: Dallas, TX
Grass Type: Southern mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by gardenpants » August 20th, 2018, 8:56 pm

I'm guessing you're using the Prodiamine 65? That's only 65% prodiamine...the rest is fillers. Your math is correct, but not complete. You forgot to divide your 4.5 tablespoons by 0.65.

gardenpants
Posts: 140
Joined: September 15th, 2016, 5:16 pm
Location: Dallas, TX
Grass Type: Southern mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by gardenpants » August 20th, 2018, 9:01 pm

What you actually put on your yard: (.3 oz of powder / K) * (.65 prodiamine) = .195 oz / K of prodiamine

kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Re: Prodiamine question on app rates

Post by kentster » August 20th, 2018, 10:15 pm

Yes, it is Prodiamine 65. Now I understand... Thank you!

Any recommendations on next steps on the application plan?


seiyafan
Posts: 1745
Joined: August 9th, 2015, 7:08 pm
Location: Orange County, NY
Grass Type: Bewitched mono and TTTF/KBG mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by seiyafan » August 20th, 2018, 10:59 pm

The label says oz per product, so it's already factoring in the 65%.

gardenpants
Posts: 140
Joined: September 15th, 2016, 5:16 pm
Location: Dallas, TX
Grass Type: Southern mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by gardenpants » August 21st, 2018, 2:03 pm

Yes. The label accounts for that. However, when trying to calculate the rate by yourself, without looking at the label, you have to remember the 65%.

kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Re: Prodiamine question on app rates

Post by kentster » November 30th, 2018, 10:27 am

Ok, I finally have some time to figure this out. After carefully reading the specimen label a few times, I think that I had the application rate correct and the label takes into account the concentration. My plan this coming season is to put down 0.25oz/k in two applications giving 0.50oz for the calendar year since I have a good bit of crabgrass and poa that I am hoping to get under control.

Questions
  • Does anyone understand why they specify the range for maximum application rate (e.g. 0.185-0.55)? Is this just a conservative to aggressive? If so, what factors might drive your decision on the spectrum?
  • It looks like the label starts at lbs/acre, but gives different conversion rates to oz/k and then even tablespoons. Is this just sloppy label work or am I missing something?
Image

Image

Kent

User avatar
andy10917
Posts: 29739
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Prodiamine question on app rates

Post by andy10917 » November 30th, 2018, 2:16 pm

Sloppy? Hell no - it's one of the best labels out there.

There are a few things at play here. The largest is that you're not looking at a label that is intended to be read by homeowners - it's a professional product and you bought it. The labels are very different from what's on a product you'd find at Home Depot. There is a ton of flexibility in the provided label - everything from what length of time you want to control weeds for, weight measurement, volume measurement, climate zone and grass type.

You need to identify your zone ("North"), and how many months of control you want (from Figure 1) and stay under the maximum amount to your grass types (NoMix is generally KBG/PR/FF). The max rate for FF is lower than KBG or PR - you'll have to decide if you have enough FF in the lawn to use the lower maximum.

Be careful not to use tables that are for landscape plants and ornamentals.

The amounts are correct for weight (lbs/acre or oz/K) or volume (teaspoons) - again, more flexibility.

This is exactly what happens when homeowners try to work with a professional product - the flexibility of the label can be overwhelming!!

seiyafan
Posts: 1745
Joined: August 9th, 2015, 7:08 pm
Location: Orange County, NY
Grass Type: Bewitched mono and TTTF/KBG mix
Lawn Size: Not Specified
Level: Not Specified

Re: Prodiamine question on app rates

Post by seiyafan » November 30th, 2018, 6:22 pm

oz is a unit of weight, tablespoon is volume, both would work but I found using a measuring spoon is easier than a weight scale.

Edit: conversion between weight and volume is not as straightforward because of the unknown density, they made things easier by including both on the label.

kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Re: Prodiamine question on app rates

Post by kentster » November 30th, 2018, 6:43 pm

seiyafan wrote:
November 30th, 2018, 6:22 pm
oz is a unit of weight, tablespoon is volume, both would work but I found using a measuring spoon is easier than a weight scale.

Edit: conversion between weight and volume is not as straightforward because of the unknown density, they made things easier by including both on the label.
Makes sense. Unfortunately, they convert differently on the same label. Thank you for reminding me about weight and volume though!

User avatar
andy10917
Posts: 29739
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Prodiamine question on app rates

Post by andy10917 » November 30th, 2018, 11:00 pm

I didn't see anything that was a bad conversion between weight and volume - can you point out the suspected problem?

kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Re: Prodiamine question on app rates

Post by kentster » December 1st, 2018, 7:27 pm

andy10917 wrote:
November 30th, 2018, 11:00 pm
I didn't see anything that was a bad conversion between weight and volume - can you point out the suspected problem?
The first screen shot shows 1lb/acre is 0.37oz/k and 1 teaspoon and the other shows 1lb/acre is 0.4oz/acre and 1.5 teaspoon.

kentster
Posts: 120
Joined: June 21st, 2018, 6:48 pm
Location: Lewisberry (South Central) Pennsylvania
Grass Type: Northern mix
Lawn Size: 10000-20000
Level: Some Experience

Re: Prodiamine question on app rates

Post by kentster » December 2nd, 2018, 9:24 am

kentster wrote:
December 1st, 2018, 7:27 pm
andy10917 wrote:
November 30th, 2018, 11:00 pm
I didn't see anything that was a bad conversion between weight and volume - can you point out the suspected problem?
The first screen shot shows 1lb/acre is 0.37oz/k and 1 teaspoon and the other shows 1lb/acre is 0.4oz/acre and 1.5 teaspoon.
Sorry, the first one actually says 1lb/acre is 0.37oz/k and 1 tablespoon

Post Reply

Who is online

Users browsing this forum: Dchall_San_Antonio and 19 guests