What Pre-Emergent Does

A pre-emergent prevents weed seeds from germinating.

It does not kill the existing plant. It stops the new root and first leaves of a germinating weed seed. That is why it is so important to get the pre-emergent into the soil, where it forms a barrier.

It won’t kill weeds you can already see. For those, see our post-emergent guides, like our Bermuda post-emergent guide.

Timing

Timing matters more than anything.

Apply before weed seeds germinate.

Simple rule: apply in the first of February, the first of May, and the first of September.

Even Coverage Matters

Apply it evenly across the whole lawn.

Smaller Particles Work Better

The smaller the particle, the better it works.

Granular vs. Liquid

Pre-emergent comes in granular and liquid forms.

Which one you use depends on the application tools you have. Homeowners typically use a granular product. Liquid is the other option.

With liquid, pros can cover more square feet per tank, but it must be watered in with as much water as possible. A pump-up sprayer doesn’t do a very good job unless you can water it in with your irrigation system or an extra hose.

Split Applications

Split applications extend how long you’re covered.

In the springtime, split applications are typically spaced 30 days apart.

Water It In

Pre-emergent has to be watered in after application.

Don’t Disturb the Soil Surface

Don’t disturb the soil surface after application.

Selective vs. Non-Selective

Selective herbicides kill broadleaf weeds and leave your Zoysia alone.

Non-selective herbicides kill everything they touch, including your grass.

Mode of Action

Mode of action is how the chemical moves through the plant.

Treat Weeds While They’re Young

Spray weeds while they are young and tender, not after they are mature. Young weeds are much easier to control.

Mixing a One-Gallon Sprayer

1. Add a half gallon of fresh, good-quality water first.
2. Add the exact herbicide dose listed on the label.
3. Put the lid on and shake well.
4. Add the remaining water.

Always Add a Surfactant

A surfactant breaks the surface tension of water. That lets the spray spread out across the leaf instead of beading up and rolling off.

Spraying Technique

Hold the wand 12 to 18 inches off the ground and aim for about an 8-inch, dinner-plate-sized spray pattern.

Spray in the Morning

Spray in the morning, not the afternoon. At dawn the plant is drinking from its roots, which helps pull the herbicide into the plant.

Don’t Mow Right Before Spraying

Mow Saturday, spray Wednesday.

The goal is maximum leaf tissue on the plant, and keeping the herbicide on the plant as long as possible before the next mow.

Then return to your regular MWF (Mow, Water, Feed) routine and mow again.

Mow Zoysia at 2–3 inches.

Selective vs. Non-Selective

Selective herbicides kill broadleaf weeds and leave your St. Augustine alone.

Non-selective herbicides kill everything they touch, including your grass.

Mode of Action

Mode of action is how the chemical moves through the plant.

Treat Weeds While They’re Young

Spray weeds while they are young and tender, not after they are mature. Young weeds are much easier to control.

Mixing a One-Gallon Sprayer

1. Add a half gallon of fresh, good-quality water first.
2. Add the exact herbicide dose listed on the label.
3. Put the lid on and shake well.
4. Add the remaining water.

Always Add a Surfactant

A surfactant breaks the surface tension of water. That lets the spray spread out across the leaf instead of beading up and rolling off.

Spraying Technique

Hold the wand 12 to 18 inches off the ground and aim for about an 8-inch, dinner-plate-sized spray pattern.

Spray in the Morning

Spray in the morning, not the afternoon. At dawn the plant is drinking from its roots, which helps pull the herbicide into the plant.

Don’t Mow Right Before Spraying

Mow Saturday, spray Wednesday.

The goal is maximum leaf tissue on the plant, and keeping the herbicide on the plant as long as possible before the next mow.

Then return to your regular MWF (Mow, Water, Feed) routine and mow again.

Mow St. Augustine at 3–4 inches.

Selective vs. Non-Selective

Selective herbicides kill broadleaf weeds and leave your Bermuda alone.

Non-selective herbicides kill everything they touch, including your grass.

Mode of Action

Mode of action is how the chemical moves through the plant.

Treat Weeds While They’re Young

Spray weeds while they are young and tender, not after they are mature. Young weeds are much easier to control.

Mixing a One-Gallon Sprayer

1. Add a half gallon of fresh, good-quality water first.
2. Add the exact herbicide dose listed on the label.
3. Put the lid on and shake well.
4. Add the remaining water.

Always Add a Surfactant

A surfactant breaks the surface tension of water. That lets the spray spread out across the leaf instead of beading up and rolling off.

Spraying Technique

Hold the wand 12 to 18 inches off the ground and aim for about an 8-inch, dinner-plate-sized spray pattern.

Spray in the Morning

Spray in the morning, not the afternoon. At dawn the plant is drinking from its roots, which helps pull the herbicide into the plant.

Don’t Mow Right Before Spraying

Mow Saturday, spray Wednesday.

The goal is maximum leaf tissue on the plant, and keeping the herbicide on the plant as long as possible before the next mow.

Then return to your regular MWF (Mow, Water, Feed) routine and mow again.