When to Apply Hi-Yield Pre-Emergent And Grass Stopper?

I hate weeding! Even with these excellent lawn-weeding tools, I still loathe the idea of spending my spring, summer, and fall fighting to free my lawn from unwanted plants. You can imagine my elation when I discovered pre-emergent herbicides.

Finally, a product I can apply to my lawn before the weeds ever have a chance to show their ugly heads. A solution like that would eliminate this back-breaking chore forever. The weed that plagues my turf is crabgrass, and the way I fight it is with Hi-Yield weed stopper.

Here’s how I use it.

When to Use Pre-Emergent?

Effective pre-emergent weed control happens before the weed seeds germinate. It is important that the treatment is applied at the correct time for it to be effective. If your application of pre-emergent is too early or too late, then there is a chance weeds will survive.

See, what happens if you apply pre-emergent too early is that it loses its potency before the weed seeds have germinated. By the time weed sprouts emerge, the herbicide is diluted, and the new plants can live on.

If you err to the other extreme, broadleaf weed killers like Hi-Yield only work on seeds as they sprout and will not affect mature or dormant weeds. If weeds are above the soil before you apply a pre-emergent, the effectiveness is heavily reduced.

Pre-emergent needs to be applied when soil temperatures reach a range that promotes weed seed germination. Hi-Yield is best used in spring and fall to prevent both warm and cool-season weeds from proliferating throughout your lawn. Some late summer and late winter applications may be needed in certain temperature settings.

Check out the table below to see when you should apply pre-emergent to your lawn.

SeasonLocation in USApply Pre-EmergentSoil Temperature Needed
SpringNorthLate Spring55℉ 2-3 days
SpringSouthEarly Spring55℉ 2-3 days
SummerNorthEarly Summer55℉ 2-3 days
SummerSouthLate Summer70℉ 2-3 days
FallNorthEarly Fall70℉ 2-3 days
FallSouthLate Fall70℉ 2-3 days
WinterSouthLate Winter55℉ 2-3 days

How to Apply Pre-Emergent?

Most herbicides can be applied via sprayer if a liquid product or with a spreader if granular. I find that spreading granular pre-emergent has given me a better return in regard to total weed control throughout my turf. When using granular weed killer, the herbicide must be watered in or applied shortly before it rains to adequately dissolve into the soil.

To apply pre-emergent, first follow these important steps:

  1. Follow the manufacturer’s instructions and use an approved applicator to evenly apply the correct amount of herbicide to your lawn.
  2. Wait for rain or water the lawn immediately to ensure all of the pre-emergent has dissolved into the soil.
  3. Avoid oversaturation of your lawn to prevent excess dilution and reduced efficiency of herbicide.
  4. Wait until the grass has dried completely, then mow to allow soil temperatures to stimulate weed seed germination.
  5. Avoid digging or disrupting the soil to prevent displacement of pre-emergent.
  6. Enjoy a weed-free lawn all year long

What Amount of Pre-Emergent is Needed to Protect My Lawn?

In order to properly protect your lawn, you will need to use the correct amount of pre-emergent. Think of this type of herbicide as a plastic barrier between the grass above your soil and the weed seeds below. In order to keep the barrier strong enough, pre-emergent must be applied to cover the whole yard satisfactorily. If there are spots with little coverage, weeds may grow there.

When using Hi-Yield to combat crabgrass, you have the option of protecting your lawn for 2-3 or 3-4 months. A heavier application is needed in southern climates than in the northern US. You will also need to apply different amounts for warm and cool-season grasses.


  • For 2-3 months of coverage, apply 2.4 lbs per 1,000 sq. ft
  • For 3-4 months of coverage, apply 3.2 lbs per 1,000 sq. ft
  • For cool-season grasses, apply 2.4 – 9.2 lbs. per 1,000 sq. ft
  • For warm-season grasses, apply 3.5 – 9.2 lbs. per 1,000 sq. ft


  • For 2-3 months of coverage, apply 3.5 lbs per 1,000 sq. ft
  • For 3-4 months of coverage, apply 4.0-4.7 lbs per 1,000 sq. ft
  • For cool-season grasses, apply 2.4 – 9.2 lbs. per 1,000 sq. ft
  • For warm-season grasses, apply 3.5 – 9.2 lbs. per 1,000 sq. ft

Never apply more than 9.2 lbs per 1,000 sq. ft. of Hi-Yield in one application.

Never use more than 27.6 lbs per 1,000 sq. ft. of pre-emergent in one year.

Hi-Yield Pre-Emergent Benefits

The active ingredient of Hi-Yield pre-emergent is Dithiopyr (Dimension). It’s an organic compound with low toxicity to humans and animals. It has been shown in lab studies to be non-carcinogenic, making it a safe and effective broadleaf weed killer for residential lawn owners.

Hi-Yield also lasts up to 4 months with proper application rates. Often, weed killers in this family only provide two months of protection, so these added months can give you peace of mind if you applied it a bit early.

Hi-Yield is synthesized with the ability to also target and eliminate newly-sprouted crabgrass as well as the germinating seeds. If you applied your pre-emergent just a tad too late, Hi-Yield can pick off the few newly-sprouted weeds and prevent you from having to apply a post-emergence herbicide as well.

How to Maximize Pre-Emergent Effectiveness?

I am confident that there is no better way to take care of pesky weed invasions than by using a pre-emergent herbicide. Hi-Yield gives me that extra satisfaction by working longer and killing new weed sprouts in addition to those just germinating. But there are ways to make it even more effective:

  1. Apply when the soil conditions are just right for your location and weeds to maximize the potency of herbicides.
  2. Always apply the correct amount of herbicide, too little will not properly cover the lawn, and too much can burn non-targeted plants.
  3. Water granular herbicides immediately to prevent the disbursement of herbicides. Once it is absorbed into the soil, it is stable and will not easily wash or blow away.
  4. Wait until the herbicide has been watered in and dried to prevent ruining the application when mowing. Mow after grass has completely dried.
  5. Do not disturb the soil through digging after pre-emergent is applied. Wait until after the weed threat is eliminated to plant or landscape.