I know you guys appreciate when I walk you through the timing and thinking behind “when to apply fall pre-emergent” so I figured today would be a good time for that.
Fall pre-emergents are driven by soil temperatures. Coming out of summer and heading into fall, soil temperatures are on the downswing. We want to get down a pre-emergent herbicide that will create a barrier in the soil that stops certain weeds from growing. This is important because these weeds are called “winter annuals” which means they germinate now, in fall time, hibernate over winter, rage in spring and drop seeds in early summer, then die. Then in fall, the cycle starts all over.
(also praying for you folks as you have one hitting you right now as I type this!!!)
So before we go any further, if you are going to seed your lawn, you should NOT apply pre-emergents. Many folks ask “what about after I seed, how long do I have to wait to apply a pre-emergent then?” I answered that in my podcast:
Now if you have not seeded, or you have any of the warm season grasses, here is who is ready to apply anytime between now and the next 10-14 days or so. I got these soil temperatures from the Greencast tool, but you can get yours for your exact house using our free lawn care app.
Ready to Throw Down Now
Least Expensive Option
Prodiamine WDG - this is the water dispersible granule formulation. You mix it in water and spray it. It’s not as difficult as it may seem and I have full training for you if you are new.
- Get Prodiamine WDG
- Get full instructions on How To Apply Prodiamine.
- Learn to How To Spray with TeeJet Tips and Using Sprayer Tips to Expand Your Liquid Application Strategy.
Prodiamine WDG Cost: $19.99
Bottle Size: 5oz or 142g
Application Rate Fall App: 13g per 1,000 sq ft
Total Product Needed for 5,000 sq ft lawn: 65g
65/142 = .45
This means you will use 45% of the bottle to get this one application completed.
.45 x $19.99 = $9.15
Your fall app on a 5,000 sq ft lawn costs under $10 !!
Aren’t you glad that you paid attention in 8th grade math class? Now you can see just how affordable DIY lawn care is!
Easier For Most - Granular
I’ve been doing this for a long time and I know that a good majority of you prefer granular applications. I feel that way sometimes too and often will choose granular options for products. The good news here is we have a prodiamine granular option that comes in a 45lb bag. Let’s look at that next. Same deal here, let’s look at a 5,000 sq ft lawn. Pretty much all grass types are going to use the 3lbs/1000 rate here which will give you 90 days of pre-emergence control (last until just before Christmas - plenty of time for most of you)
Prodiamine Granular Cost: $49.99
Bag Size: 45 lbs
Application Rate Fall App: 3lbs/1,000 sq ft
Total Product Needed for 5,000 sq ft lawn: 15lbs
15/45 = .33
This means you will use 33% of the bag to get this one application completed.
.33 x $49.99 = $16.50
Your fall app on a 5,000 sq ft lawn costs $16.50
We have one other option, granular dithiopyr, for those of you who may have used up your calendar year allotment of prodiamine. There is a max amount you are permitted to use. Others of you may just prefer dithiopyr. You can get that here in granular.