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  • Writer's pictureLVHG

How Herbicides Work and How To Use Them Effectively

Herbicides are widely used in gardens, but their mechanism of action is not well understood. We know they act as our magic makers for deterring weed growth in the garden, but how do they do this? Herbicide science is a rabbit hole of knowledge. So, let's put this into terms we can all understand. This blog features pre-emergent and post-emergent herbicides, organic options, and more, explaining how they work and empowering you to choose the right type for your needs!

How Do Herbicides Work?

Herbicides have been used for many years to manage weeds in crops and landscapes. Herbicide performance is affected by various factors, including climate conditions, herbicide uptake, translocation, and metabolism.

A contact herbicide destroys only the plant tissues that are in contact with the substance. They are quick-working herbicides but less effective on perennial plants.

In contrast, systemic herbicides move through different parts of the plant. These are more effective at controlling perennial plants but act more slowly.

Pre-Emergent vs. Post-Emergent Herbicides & When To Apply Them

The main difference between these two groups is that post-emergent herbicides kill weeds after they emerge from the ground, while pre-emergent ones kill the weed seed as it germinates in the soil.

Pre-Emergent Herbicide

Pre-emergent formulas are less harsh than your typical weed killer; however, many factors can reduce the effectiveness of pre-emergent herbicides, such as soil, sun exposure, and water. Still, this type is excellent for giving you a head start on weed control and reducing what will come up through the season.

You will want to apply your pre-emergent herbicide from August to November to combat cool-weather weeds and apply around mid-March to get ahead of spring and summer weeds.

Post-Emergent Herbicide

Herbicides used post-emergently control weeds that have grown above ground. During early to late spring, just when the weeds have shown their ugly little heads and are still small but growing rapidly, is the best time to apply your post-emergent herbicides. As the germination process has already begun, pre-emergents are no longer effective at this time of the year.

Process of Selection

We know what you're likely thinking. If herbicides effectively remove weeds in your garden, what effect will they have on your other plants? Choosing an herbicide based on soil type, pH, and organic matter content is essential for minimizing crop injury and damage to the plants you want to protect.

You can also choose between selective and non-selective herbicides. Selective herbicides use certain chemicals to target weeds without harming your lawn, whereas herbicides that are not selective will kill all plants they come in contact with; you have to be careful applying non-selective types!

Extra Things to Consider

Here are some additional considerations for choosing the right herbicide for your garden:

1. Read the label. The herbicide label includes information on how much herbicide should be applied to each area, product handling guidelines, and what time of year/where you should apply it.

2. Ensure your herbicide rate aligns with your soil type and weed volume.

3. Be conscious of the nozzles you are using to apply the chemical herbicide. Ultimately, the amount of herbicide applied is determined by the nozzle and spray pressure, which determines the uniformity of the application and the coverage. Essentially, you want to ensure that your herbicide only goes where you want it to go!

4. Monitor the weather during the times you choose to apply your herbicide. A calm, cool day is the best time to apply your herbicides.

Visit us at Lehigh Valley Home and Garden in Allentown, Pennsylvania, to find the perfect herbicide to restore life to your garden. With our expert knowledge, we can help you with various garden solutions. Why wait until tomorrow when you can start saving your garden today?


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