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 Lawn

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

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:

  • Weed Prevention Plus by Concern: 100% Natural Corn Gluten Pre-Emergent Herbicide. This one provides control of dandelions, crabgrass and other common lawn and garden weeds and is designed for use around roses, flowers, bulbs, vegetables, trees, shrubs and on lawns. It's also ideal for use under bird feeders. 
  • Weed Impede by Monterey: Pre-Emergent Herbicide for control of annual grasses and many broad-leaf weeds. Use it in landscape ornamentals and bulbs, rock gardens, ornamental bedding plants, ground cover and non-planted areas. 
  • 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. "100% Corn Gluten Meal by The Organic Garden Guy: This special Southwest formula prevents weed seeds from germinating. Use it in gravel areas, gardens and flowerbeds.  
  • Natural Pre-Emergent & Fertilizer Lawn Formula by the Organic Garden Guy: This 100% Corn Gluten Meal pre-emergent stops weeds before they start and feeds your lawn naturally.

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!


About SummerWinds Nursery

A leading high-end retailer of garden and nursery products. Headquartered in Boise, Idaho, SummerWinds Garden Centers, Inc. operates retail nurseries in the greater Phoenix, Arizona area, and in Silicon Valley, California, making it one of the largest independent retail nursery companies in the nation. SummerWinds appeals to both the serious and casual gardeners, with a broad selection of premium gardening products and a friendly and knowledgeable staff.