Pre-emergent herbicides, also known as crabgrass preventers, are effective at preventing undesirable weed from growing in your lawn. They don’t stop the weed seed from germinating but helps control it so that it does not sprout. They do so by inhibiting a key enzyme.
A good example is Dimension pre-emergent. The active ingredient in Dimension is Dithiopyr. It works both as a pre-emergent and post-emergent, and can thus be the best choice in areas with unpredictable weather. Being a water-based herbicide, it can be used established lawns, over the top of the field, landscape ornamentals, container-grown nurseries, and commercial sod farms among other places. It works on grasses such as barley, brome, barnyard grass, crabgrass, bluegrass, and broadleaf weeds like carpetweed, geranium, bittercress, mulberry weed, lespedeza and knotweed among others.
You never have to use a weed puller any more unless you love the manual labor.
The best time when to apply dimension pre-emergent is in the spring and fall. Here are other important things to note to help achieve desirable results:
- During the spring, apply when air temperatures reach 65-700F for four consecutive days.
- During the fall, apply when nighttime lows get to 55-600F for four consecutive nights.
For winter annuals, you should apply the pre-emergent in fall since that is when the seeds germinate. For summer annuals, the seeds germinate in spring and that is the best time to apply a pre-emergent.
Pre-emergent weed killers need water for activation and carry the chemical down to the root systems of newly-sprouted weeds. Dimension needs to be watered in with about 1/2 inch of water for it to be activated. Another option is to apply it before the rain and let the rainwater in. You can always use the sprinklers to make artificial rain.
Like any other pre-emergent herbicide, once you apply Dimension pre-emergent it can last up to 3-4 months. You will have to wait for at least this period before seeding your lawn. Before that, it will not allow your grass seeds to germinate. As for the shelf life of the product, it will depend on how well you store it. If properly sealed and stored away from direct sunlight and extreme temperatures, the shelf life is between 3-5 years.
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With the above pre-emergent weed control tips you can make the most use of your Dimension to get the results you are looking for. It is safe to use but always ensure you read the label and follow the given instructions for treatment programs.