Fall Pre-emergent Time is Nearing

I understand how preachers feel on Sunday mornings. All you can do is pour out the message and hope someone is listening.

You get one chance to stop winter grasses from making your lawn look ugly. Only one chance, and it comes in the form of pre-emergent weedkiller granules.

With non-grassy (broadleafed) weeds you get a second opportunity in the form of broadleafed weedkiller sprays (containing 2,4-D) that can be applied to existing weeds.

Photo: Annual bluegrass (Poa annua) can only be prevented, not killed.

Here are the critical details…
“Pre-emergent” means you must apply these products before weed seeds germinate (“emerge”).

Grassy weeds that are almost ready to sprout: annual bluegrass (Poa annua), rescuegrass, ryegrass.

Broadleafed weeds that will germinate and start growing soon: clover, dandelions, henbit and chickweed.

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Products that will prevent germination of grassy weeds: Team, Dimension, Balan or Halts.

Product that stops sprouting of non-grassy (broadleafed) weeds: Gallery.

Photo: Germination of dandelions can be prevented by application of Gallery late this month.

These products are safe on any type of lawngrass as long as it is mature (has been through at least one winter). They will not cause damage to trees and shrubs.

Timing: Granules must be applied last week of August and no later than September 7. (Watch my Facebook page to see how many people ask “Neil, is it too late to apply pre-emergents….” weeks after those dates.)

If you intend to apply both types of pre-emergents you will have to do so in two passes across your lawn. Do not try to mix them. Mow your lawn first, then make the two treatments and water moderately to spread them across the soil surface.

Do not apply pre-emergent herbicides if you intend to overseed your lawn with ryegrass.

Posted by Neil Sperry
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