What You Need to Know About Pre-Emergents
Posted on: Tuesday, September 6, 2022
Pre-emergents Prevent the Germination of Seeds by Controlling a Key Enzyme in Weeds
According to The Dandelion King in the New York Times, "'Pre-emergent' herbicides are laid down more than once in the spring (mixed in with the fertilizer) to sabotage the germination of crabgrass, dandelions and other undesirables. If this fails, post-emergents may be applied en masse. And as the summer wears on, local pockets of resistance can be wiped out with a spray canister of poison."
Before you put down an application of pre-emergent, consider these tips rounded up by West Coast Turf:
1. Irrigate afterwards; water activates pre-emergent herbicides.
2. Measure your lawn surface area and calibrate your spreader properly prior to application. Applying more herbicide than is necessary could cause damage to your lawn and plants.
3. If you are starting to see a small emergence of crabgrass or poa annua after applying the product, it's okay to treat a second time over the missed areas. Make sure you consult the product's label for proper use prior to making a second application.
4. If you have installed your turf within the last 3 months, withhold all pre-emergent herbicide applications so you do not damage the root system.
Safety Tip - Be certain to follow the product instructions to ensure your turf is safe post-treatment for your children and pets.
Fall Applications of Pre-Emergent
Before you put down an application of pre-emergent in the fall, your Trusted Garden Advisors at SummerWinds Nursery recommend the following:
1. Apply the pre-emergent in September or October to control winter weeds that come with January rains.
2. Keep the pre-emergent away from your lawn area if you're over-seeding your lawn with winter rye seed. Be very careful not to get it in your lawn area, as it will prevent the rye seed from germinating.
3. However, do apply pre-emergent to rock and ornamental areas to prevent accidental germination of any rye seed that may have unintentionally made it into that area when you were over seeding.
4. Be certain to apply the pre-emergent according to directions and irrigate as indicated.
Using Pre-Emergents Effectively
As the University of Arizona explains, "Pre-emergent herbicides are only effective if they are incorporated into the soil using at least ½ inch of rainfall or irrigation water shortly after application. Pre-emergent herbicides applied to rock must be washed or carried through the rock mulch and into the soil in order to be effective. Pre-emergent herbicides cannot be washed off of organic mulches (e.g. wood chips) and should not be used on these types of mulches."
Pre-Emergents We Offer
Stop by your local SummerWinds store to pick up one of the following pre-emergents:
- Crabgrass & Weed Preventer for Lawns & Ornamental Beds by Bonide - For use on both cool and warm season turf grass. It provides control of crabgrass and many other weeds in established lawns and residential landscapes.
- Season Long Weed Control for Lawns by Bayer - For use on established lawns, this product kills and prevents weeds for up to 6 months; protects against 200+ weeds.
- Turf & Ornamental Weed & Grass Stopper by Hi-Yield - For control of crabgrass and control or suppression of other listed annual grasses and broadleaft weeds in ornamental landscape areas, established lawns and ornamental turf. Can be applied up to 4 weeks later than other preemergence crabgrass preventers - see package for details.
- Vegetable & Ornamental Weeder (Weed & Grass Preventer) by Monterey - Use in ornamental and vegetable gardens to control annual grasses and broadleaf weeds
Keep your garden weed free by using the above tips and advice for pre-emergents, and stop by one of our stores and pick up yours today! While you're there, don't be shy about asking one of our experts for additional insight; we're happy to help!