When embarking on weed prevention, there are two primary types of weed killers, pre-emergent herbicides and post-emergent herbicides. Knowing the differences between these two types of weed killers and how to correctly use them during the year will make a huge difference in how effective your weed killing pursuits will be during the growing season.
This type of weed killer is used early in the spring, before plants really begin to grow and the weather turns warm. A pre-emergent herbicide creates a protective barrier seal around seeds, which prevents the seed from germinating and growing. In essence, the seed is suffocated and dies.
Pre-emergent herbicides are used early in the growing season. They are best applied when the temperature is lower than 60 degrees and the soil is just beginning to warm.
You can apply the herbicide to the soil either by spraying it in liquid form or by spreading it in granular form. The soil will absorb both forms. Water activates the granules. Either a spring rainfall or watering with a sprinkler system after the granules have been spread will be an effective way to activate the granules.
Pre-emergent herbicides are only effective on weeds, like crabgrass, that annually sprout from new seeds. These herbicides do not effectively treat perennial plants like established quack grass because they have a deep root system and simply reemerge every year as the weather warms.
The other type of weed killer is a post-emergent herbicide. This type of weed killer is used once the initial spring season has begun and plants have started to grow. Once a plant has started to grow it is too late to utilize the germination prevention of a pre-emergent herbicide and it is time for you to apply a post-emergent herbicide.
Post-emergent herbicides work by traveling down the plant stalk and into the root system. If you are using the liquid form of the herbicide, apply it directly to the weeds. It is better to apply the spray after the base of the plant has been cut or torn away because the plant structure will be open and the herbicide will go directly into the plant system.
If you are using the granular form, apply the herbicide to the lawn with a spreader and then activate it with the lawn sprinklers.
Post-emergent herbicides usually need to be applied several times throughout the growing season. Often, a thorough final application during late fall will help prevent new weeds from growing in the spring and prevent weeds from spreading seeds.
It is important to understand the difference between specific and non-specific herbicides. Specific herbicides are most commonly used for lawn care and other weed elimination efforts by homeowners. They specifically target weeds and do not usually harm other surrounding or adjacent plants. A non-specific herbicides, on the other hand, will kill all plants it comes into contact with. It is most commonly used by landscapers or developers who are clearing a lot or area for a new building or for landscaping purposes.
Should You Be Aerating Your Lawn?
One of the most common questions from homeowners is how to determine if they should be aerating their lawn. Your lawn is probably a good candidate for aeration if it:
Gets heavy use, such as serving as the neighborhood playground or racetrack. Children and pets running around the yard contribute to soil compaction.
Was established as part of a newly constructed home. Often, the topsoil of newly constructed lawns is stripped or buried, and the grass established on subsoil has been compacted by construction traffic.
Dries out easily and has a spongy feel. This might mean your lawn has an excessive thatch problem. Take a shovel and remove a slice of lawn about four inches deep. If the thatch layer is greater than one-half inch, aeration is recommended.
Was established by sod, and soil layering exists. Soil layering means that soil of finer texture, which comes with imported sod, is layered over the existing coarser soil. This layering disrupts drainage, as water is held in the finer-textured soil. This leads to compacted conditions and poor root development. Aerating breaks up the layering, allowing water to flow through the soil more easily and reach the roots.
When to Fertilize
When and how often you should apply fertilizer to your lawn depends on the type of grass you grow. Grasses need nitrogen and other nutrients during their seasons of active growth, and they grow best with an even supply. Fertilize grasses when it’s naturally dormant, and you’re wasting fertilizer. Space your applications too far apart, and your grass grows fine for a while, then slows down, and then speeds up again with the next application.
Warm-season grasses, like Bermuda grass and St. Augustine grass, grow rapidly in warm weather. Generally, you need to feed warm-season grasses from late spring to early fall. If you feed too early in spring the nitrogen likely promotes rapid growth of cool-season weeds. You don’t want that. If you fertilize too late in fall, the grass is likely to be less hardy as it enters cold weather and more susceptible to winter injury.