Controlling Crabgrass and other Summer weeds require very early prevention methods. Using a pre-emergent herbicide in early Spring is the most time-proven method to prevent weed seed from germinating later in the season. Here we talk about pre-emergents mode of action, and compare two of the most important weed prevention products available to consumers.
How Pre-Emergent Herbicides Work
Annual weeds, like Crabgrass & Nutsedge, spread seed during the end of Fall, and are moved by wind, raking, and snow runoff. These seeds remain in the thatch layer and attempt to germinate once the tempuature reaches a suitable level.
Pre-emergent herbicides are formulated to prevent these seeds from being able to perform this initial germination process. Timing is very important as too early poses the risk of herbicide deactivation, and too late poses the risk of missing the germination window.
Prodiamine, also known as Barricade, is one of the two most widely used lawn pre-emergents for weed control. It is most commonly found in soluble granular form, which are bright yellow in color.
This herbicide is known to have a shorter window of protection than Dimension. It is however known to work a bit better on pre-emergent control of crabgrass, and less so on Sedges.
Prodiamine can be made into a very easy to use spray formula for a lower cost than Dimension in most cases. However there aren’t many pre-mixed fertilizer pre-emergent combinations available as in the case of Dimension.
Labeling allows for 2 full strength treatments per year, as opposed to one full, or two split, treatments per year with Dimension.
Dythipyr, also known as Dimension, is held with high regard in the lawn care community. This is due to it’s high level of flexibility. It is most commonly founf for consumers in pellet form, pre-mixed with some sort of Fall Fertilizer. It is found in liquid concentrate, but is restricted for licensed companes in most states.
Dimension has a longer window of effectiveness. It’s pre-emergent properties can last up to 90 days. It also has post-emergent properties for very early Crabgrass and Nutsedge growth. Keeping in mind the initial investment of a spreader or sprayer.
Dimension can be easier to use with store bought pre-blends, and use of a broadcast spreader. It usually does end up being more costly than Prodiamine due to markup from these conveniences.
I often find that homeowners have better results with Prodiamine because a pre-mixed granular formula can make it difficult to apply a high enough concentration of the required herbicide. However, in my experience, professional applicators seem to have better results with Dimension overall compared to Prodiamine. This may be due to their ability to adjust application rates, safely mix with other chemicals, and to customize blends for unique lawn conditions.
It is important to remember that no one chemical controls every weed. Formulations have their strengths and weakness when compared to others. You will have to do your due diligence and decide which product will provide the best results for your specific conditions.