3 images: Gaillardia planted with mulch near concrete border and a lush green lawn; a beautiful Arizona house with a variety of plants surrounded by mulch and large rocks; and cacti and desert flowers in a desert landscape with red rock mountains in the background

What You Need to Know About Pre-Emergents

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."

Dog on Lawn

Applying Pre-Emergents

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.

Over-Seeding Your LawnFall 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. Apply before the cooler temperatures of late fall, which promote the germination of weeds.

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.

Pulling a dandelion weed out of the soilSpring Applications of Pre-Emergents for Summer Weeds

To prevent late spring and summer weeds, we recommend applying pre-emergents in the late winter or early spring. This is usually around February or early March, before the temperatures consistently rise above 55-60 degrees Fahrenheit at night. This timing helps prevent the germination of common summer weeds.

Using Pre-Emergents Effectively

Grass meets rock

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. 
  • ProZone Weed Beater® Complete by Bonide - Provides both pre-emergent and post-emergent systemic control of weeds from the leaves to the roots. Works on cool and warm season grasses to control nutsedge, goosegrass, ground ivy, and other broadleaf and grass 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!

At SummerWinds, We Guarantee Success!