Success With Pre-Emergent Herbicide – Avoid Common Misconceptions to Ensure Success

Success with Pre-Emergents
There may be snow on the ground – but we all know it won’t be there for long! Our very own Mike Frank from our CPS Longmont branch has taken the time to remind us of all the Myths and Facts surrounding Pre-Emergents. Take a look!

7 Common Myths & Facts Concerning Pre-Emergents:

1. There were no prior issues so really no need for a pre-emergent application this year.

Weed seed travels great distances by wind, birds, rodents etc. It is guaranteed that there is weed seed lurking in the turf just waiting to sprout and ruin your day.

2. Thick healthy turf won’t need to be treated.

While it is true that a good healthy lawn makes it difficult for weeds to survive, there is no guarantee that the turf will hold that vigor through the heat of the season. Weeds love heat and drought stressed turf. It is their opportunity to shine through. A pre emergent application will make sure they don’t succeed and that your turf returns to glory when the heat subsides.

3. Soil aeration breaks the control barrier if done post application.

The jury is still out on this one. There are several published reports that say there is no declination in control if aeration is done after the pre-app. These reports come from highly controlled settings. In a real world setting it would be best to apply after aeration. However, if you have to apply pre aeration you should be “OK”.

4. Spot treating is as effective as blanket treatments.

You may feel that you are saving money by only treating hot spots along drives and sidewalks. However, the general consensus says, that’s not so. Consider the cost of return visits to address complaints of weed break through beyond the original “spot” treatment. This is a financial cost to you as well as a customer satisfaction consideration.

5. Post emergence is better and cheaper than pre-emergent applications.

Early applications with pre-emergence allows for turf grass to achieve a fuller canopy. Later season post emergent applications can stress your turf. And leave voids in the grass where weeds had taken over. In addition, waiting for weeds to emerge can create a rush on your part to treat before a customer complains. There are also customer considerations to think about, customer dissatisfaction can last longer than you would like.

6. Pre-emergent applications must be applied at an exact time.

There are several factors that people go by such as Mother’s Day, the right month or the blooming of the forsythia. While these are a general rule of thumb, crabgrass seed begins to germinate when soil temperatures hit a constant 50 degrees F. You will want to have your application down just before this happens even if your application is a little early. It is important to understand that a pre-emergent does not prevent a seed from germinating. It inhibits shoot development through enzyme inhibitors which breaks the branched chain amino acids thus killing the shoot.

7. Pre-emergent is the same as a ground sterilant.

This statement is nowhere close to being correct. Pre-emergents work on the chemistry of the sprout starting to come out of its seed shell. See number 6 above. Ground strerilants do just what they say. They kill all vegetation and some formulas can be active for up to 10 years. Ground sterilants have no business in the landscape or garden as they easily leach and run off target. These chemicals are responsible for hundreds of unintended tree and other vegetation deaths each year!

Also important for success is that a correct amount of precipitation be applied through irrigation or natural rain/snow fall to wash the product into its protective layer within the soil. You must also apply per label instructions at the correct rates for successful applications. All of this holds true for any type of pre-emergent herbicide application.

Happy Pre-emerging!