Northwest Ohio - IS IT or ISNT it time to put down crabgrass preventer??

Im hearing all kinds of answers from the lesco rep, the co-op rep, toledo turf rep, and guys on here.. some companies are out and about, some are waiting... with the mild spring we've had in NW ohio, is it too early to put down crabgrass preventer or not... too many varied opinions out there - need some fact... if i can get this done now, i wanty to get it done.. but ive always been told APRIL 1st to APRIL 15 - no exceptions...

educated help please...

 

The question is when is it too late. Your extension agent can help you with that. If the ground is not frozen you should be fine putting it down now. The product (whichever you use) will only be effective for a certain number of days. The later you put it down, the later it will be effective, which is helpful to your customers. The larger companies are driven by the volume of customers they have. If they don't start early they will not get every client done in time. In this part of Michigan (near Ann Arbor) the first week of May sees temps where they need to be for crabgrass germination. If I have customers sign up in that window, I still sell them the first application, but I switch to Dimension which has post-emergent control on very young crabgrass.

 

right out of the Ohio Lawn Care Association newsletter I just got. Northern Ohio 4-1 to 5-1 is best and southern ohio 3-1 to 4-1 is best. Of course it will very with weather a little.

 

University studies years ago showed that late fall applications of pre-em were effective the following season. Timing of late fall apps depends on your temperatures in your area.

Pre-ems are basically broken down by microbal activity, and in northern climates, as temperatures cool down for winter, microbal activity comes to a halt. In my area, any pre-em applied on Dec 1 would still all be there on April 1. Most all of a Nov. 1 app will still be there next spring.

Bottom line, with most pre-ems, you never need to worry about being too early. But too late can often be a problem.

 

Groundkprs,

I'm not second guessing your statement. I'm just wondering if there is any information on results with large snow fall conditions or heavy spring rain with frost still in the ground? Would this have any effect on a late fall or early spring pre-em applications?

 

2 man, I don't have time to research an exact answer for you. That would be a good question to ask your state turfgrass extension people next time you see them.

I would not apply to frozen ground, because it could likely wash off, or get concentrated in low spots, stressing the turf in those areas. But as long as ground is not frozen, and temps are low - therefore no microbal activity - you can apply. But once applied and watered in, pre-ems by their nature bond in the first 1/8" to 1/4" of soil. Rain or snow will not move them, but I think excess rain at more elevated temps can help increase active microbe populations, therefore speeding the degradation of the chemical.

Here last year we had excessive rain in late spring, and my Snapshot in parking lot gravel beds was not as effective as long as normal. I don't think the rain itself caused this, but the rain enhanced environmental conditions for a quicker breakdown of the barrier.

 

Use the tried and true methods as when to apply your preemerge's. Apply when the petals the forsythia begin to fall.

Crabgrass will begin to germinate when the soil is 50 degrees or above measured in the upper half inch of the soil. It is best to take your reading in the morning.

 

thanks guys - your help is greatly appreciated !!

 

Saw in one of the trade mag that crab will germinate when soil temps is between 50 and 55 degrees at the 2 inch depth. I believe that info was from penn state or ohio state

In early 80's, I saw some research where crabgrass needs minimum of 3 consecutive days of 55 degree soil temp at the 3 inch depth. I have used this method for @ 20 years, and have never been burned! I always chech the soil temp at sunrise in normal turf density!

Now must of the time I used this on gc turf, so I could water in immediately, didn't have the problem with soil warming up quicker along walks and driveways!

Goosegrass needs @ another 5 degrees to germinate. Again, this method will give you a few days to apply, and is the drop dead date to prevent crabgrass!

I basically agree with groundkeepers about late fall application of pre emerge, except I believe it slightly reduces the length of control! You must take into account what product and rate applied to determine the length of control!

 

I tell everyone up here in Northeast OHIO
it must be done by the last week of March.
Last year it got warmer earlier and I noticed crabgrass germinating on some of the new accounts we started in April.
2nd or 3rd week of march would be ideal.