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Pre-emergents for Weed Control

The days are getting longer, and spring has finally sprung.

Weeds have become an increasingly frustrating sight, taking control of your beautiful yard and garden. Broadleaf weeds, such as dandelions, plantain, and clover, have reared their ugly heads. The broadleaf weeds will be treated with the Late Spring Application once the weeds start actively growing. It is important to get the pre-emergent crabgrass control down before the crabgrass germinates.

Understanding Crabgrass and Controlling it.

Crabgrass is a summer annual grassy weed. This means the plant itself only survives for a season. Towards the end of its growing season, usually July-August, it will produce seeds. The seeds will mature on the plant and fall off onto the ground. The seeds will remain in the soil until the following spring. Once soil temperatures reach 55-60 degrees and if there is adequate soil moisture and sunlight, the seeds will germinate to start the life cycle all over. To prevent the seeds from germinating, a pre-emergent should be applied before the seeds germinate. This is why it is important to apply the pre-emergent in the early spring.

Will the Pre-Emergent last all season?

Under normal conditions, a properly timed and applied pre-emergent application will last all season. There are a few factors that can impact the longevity and effectiveness of the pre-emergent. Probably the biggest factor is what material and at what rate it is being applied. Royal Greens only uses the top performing pre-emergent. This season we will be using Dimension. The application rate is also a major factor. We use the recommended rate for the Washington/Baltimore area. Another factor is the current condition of the lawn. If the lawn is thin and has bare spots, and had a lot of crabgrass in it the previous season, there is a good chance that 100% crabgrass control is not going to be achieved. Thickening up the lawn by proper fertilization and/or seeding will help greatly to control crabgrass.

Should I seed in the Spring?

In a word NO! There are several reasons why it’s not a good idea to seed in the spring. A pre-emergent cannot be applied if you put down grass seed. Grass seed, like crabgrass seed, will not germinate until soil temperatures reach 55-60 degrees. Typically that doesn’t happen until mid-end of April. By May, temperatures can reach the mid-high 80’s which will burn the new immature seedlings out leaving you nothing but a weed patch.

Japanese Stilt Grass.

In recent years Japanese stilt grass has become very prevalent in our area. It is another summer annual grassy weed. It differs from crabgrass in that it germinates earlier in the spring and it likes a more shaded environment. It commonly can be found encroaching into lawns from wooded areas. Control of Japanese stilt grass is more difficult than crabgrass. There are fewer materials labeled for its control and they are less effective. Applying the pre-emergent early and having a dense stand of grass are the best means of control.