Fall Pre-emergent Time is Here
You have the chance in the next 10 days to do something that will pay dividends clear into late spring. Make your applications of pre-emergent herbicides before September 7. Winter weeds are set to start sprouting. It’s better to be a week too early with the preventive treatment than one day too late.
Pre-emergent weedkillers are applied before weed seeds germinate. They disperse across the surface of the soil, forming a layer of protection that kills the small seedlings just as they try to get started.
Facts You Need to Know
• Weeds controlled: winter weeds that germinate in fall, grow over the winter, and become unsightly from late winter through spring.
• Grassy winter annual weeds: annual bluegrass, rescuegrass and ryegrass.
• Broadleafed (non-grassy) annual winter weeds: dandelions, clover, chickweed and henbit.
• Products to use for grassy weeds: Halts (available from national chains), Dimension (available at local independent retail garden centers).
• NOTE! These products will be labeled as “crabgrass preventers.” That’s because their prime sales come in spring, when you’d be applying them to prevent germination of crabgrass and grassburs. The same products prevent winter grasses if applied at this time.
• Product to use for broadleafed weeds: Gallery (available from local independent retail garden centers).
• You must make two passes over the lawn, one with each type of pre-emergent. (That assumes you decide to use both types.) Do not try to mix them before application. Granule size variations will prevent uniform mixing.
• Sequence of fall lawn care:
1. Mow grass.
2. Fertilize with an all-nitrogen lawn food that has half or more of its nitrogen in slow-release form.
3. Water deeply.
4. Wait two days.
5. Apply pre-emergent weedkiller(s).
6. Water lightly to disperse herbicide(s) across surface of soil.
• You must not use pre-emergent weedkillers if you intend to overseed your lawn with ryegrass. Do one or the other.
• Do not apply pre-emergent weedkillers where you intend to sow wildflower seeds.
• Do not apply pre-emergent granules if lawn is less than four months old. It will inhibit good rooting of new sod and seed.
• Pre-emergent weedkillers are safe around trees and shrubs when used according to label directions.