Early Spring and Fall are the most effective times to apply pre-emergent herbicides. They can be applied throughout the year, and will still prevent new weeds that sprout, however most weeds sprout during spring and fall.
“If an applicator applies too much herbicide, not only is it not cost effective and a label violation, this may injure the desired turfgrass depending on the rate and product used. An excessive application may also prevent the proper establishment of grass seed later in the season.â€
Re: Siduron/Tupersan is being discontinuedIt is labeled to suppress bermuda in bentgrass. I am sad to hear this since it is the first weed killer I used in conjunction with seeding at my first house ages ago.
The Best Pre-Emergent Herbicides:
- Prodiamine (Barricade equivalent) is the longest-lasting, and most economical due to lowest application rates.
- Isoxaben (Gallery equivalent) prevents a very large list of Broadleaf Weeds.
- Oxadiazon (Ronstar equivalent) is a great granular option – safe in all turf and ornamentals.
Once some pre-emergents are applied, you only have to wait seven to 10 days before reseeding. The same is true of laying sod after pre-emergent. Rake over any bare spots and turn over the dirt. Topsoil can be added to any remaining bare spots, as this will enrich the soil.
Overseeding might help crowd out some of those weeds but most will just return without a pre emergent. Pre emergent planning should start in the Spring before weeds start germinating and the timing in NJ is roughly late March early April depending on the weather.
Apply pre-emergent herbicide and fertilizer at the same time in spring to kickstart your lawn. Pre-emergent and fertilizer work well together because both need to be watered into the soil to be effective. Plus, you only need to spread one product, reducing the amount of work required to launch your spring lawn.
Weeding is an effective, targeted way to kill weeds in a lawn.
- Dig weeds up by the root using garden tools such as a dandelion digger or sickle blade.
- Weed seeds can lie dormant for years, so avoid perennial weeds by not digging too deeply.
- Weed early and often.
- Hoe planting beds regularly with a dutch or push hoe.
When to Apply Post-Emergent HerbicidesPost-emergent herbicides work best in the late spring, when emerging weeds are small and actively growing. It is much easier to kill small weeds, and actively growing weeds are more likely to take the herbicide and move it through the entire weed, even down to its roots.
Since these weeds are already germinated, a pre-emergent has no effect on them. (But it will prevent any seeds they dropped the previous year from germinating. Call it a partial win.) Treat them with spot applications of post-emergent herbicide that targets roots, like Roundup.
Important: Pre-emergent is not designed to control existing weeds or weed seeds. The weed will only be killed when it begins to sprout from the seed and hits the herbicide barrier. It is possible for seeds to remain dormant and not be harmed by the pre-emergent herbicide application.
We recommend considering a pre-emergent application in the late winter to early spring to maximize its effectiveness. Every pre-emergent product is a bit different, but you can expect a single treatment to last approximately 3-5 months.
Any tricks for killing weeds in the lawn without killing grass? Pre-emergent and post-emergent herbicides are designed just for this. Both are made especially for weeds. So, the pre-emergent for crabgrass or post-emergent for dandelions were created just for those plants.
The best time to control lawn weeds is when they're actively growing, unless you're trying to prevent weeds from appearing. In that case, you must apply a pre-emergence weed killer before the weeds begin to grow. Post-emergent weed killers control weeds that are already visible in the lawn.
