Is the idea of applying pre-emergent before a warm-weather lawn care task enough to bring on a panic attack? You may not know how much coverage you need, when to apply it, or what other products should be mixed with it. What's worse is that even if you do everything just right and have an amazing looking lawn afterwards, your neighbor might not want to talk to you for days! But fear not! Here are some tips to help form a lawn care plan from one dedicated gardener about when and how to apply pre-emergent so your yard can stay healthy all summer long.
What is Pre-Emergent?
A pre-emergent herbicide is a chemical composition that is used to prevent the growth of weeds. Before the pre-emergent gets applied, you might have an ugly lawn with weeds popping up everywhere. Once their job has been completed, which can last for up to 90 days depending on the specific product being used, there will be no need for further actions unless another are chemicals that block or destroy certain plant seeds, stopping them from germinating. They work by preventing the development of the embryo within its protective seed coat. Pre-emergent herbicides are especially common in gardens and agricultural settings because they prevent weed growth on paths, sidewalks, around trees, along fence lines, etc. without requiring any action after they have been applied.
When to Apply Pre-Emergent
Pre-emergent need to be applied before the weed seedlings emerge in order for them to work correctly. It is essential to apply it before weed seeds begin to germinate, or produce young plants. Some weeds emerge early such as dandelions, while others such as star thistle can germinate in the fall. It is common for gardeners and farmers alike to use pre-emergent products when planning out areas such as gardens and lawns where a pre-emergent herbicide is an agricultural chemical that prevents weed growth when it has been applied. It can be used to preserve gardens, sidewalks, and other surfaces from the germination of weeds in them. In addition, they are often used in agricultural settings to prevent weeds from growing in between crops or trees without needing any further action after initial application. A common type of pre-emergent is a granule that contains both fertilizer and chemicals that destroy plants' embryos. Once these granules have been placed in a certain area, they must dissolve into the soil before their job has been completed to prevent anything from being destroyed by them. This will prevent them from working before their intended time. Pre-emergent herbicides are often used in agricultural settings to prevent weeds between crops, trees, and lawns; they are most often used in gardens to keep paths, sidewalks, and garden beds weed free throughout the year without additional actions after application.
Fall Pre-Emergent
A pre-emergent should be applied in early fall before any grassy or broadleaf weeds can germinate. There are several different types of herbicides, each with different application dates. Consult the label on the product you are using for specific instructions about how to apply it correctly and when to do so. Pre-emergents are intended to prevent annual weed growth during the winter months between fall and spring. It is important that they are applied before or at least at the same time as your first frost date in order to keep your lawn free from weeds all season long. You should apply a pre-emergent after Labor Day in areas where cool-season grasses will grow and before the first frost or freeze in areas where warm-season grasses will grow.
Liquid vs. Granular Pre-Emergent
Liquid Pre-Emergent Herbicide
Liquid pre-emergent is most effective when applied to moistened lawns or freshly watered landscapes where you want to kill newly germinating weeds, such as crabgrass and other yellow and green foxtails. A common active ingredient in most brands of liquid weed killers is pelargonic acid, a fatty acid found in plants. When applied, it penetrates the outer layer of a weed and destroys its ability to produce proteins, eventually killing it. Liquid pre-emergents are most effective when they are watered into the soil right after application . This allows them to spread throughout the lawn without being washed away before they have time to take effect. Liquid weed preventers can also be used on areas where you don't want an established lawn, such as driveways or walkways. Granules of pre-emergent herbicide do not provide coverage along building foundations, sidewalks or driveways well -- liquid weed killers do. However, liquids are usually cheaper than granular types that release chemicals over time because they are reapplied every few weeks.
Granular Pre-Emergent Herbicide
Granules are also made from pelargonic acid, but they release the chemical more slowly. To prevent weed seeds from germinating, granules are best applied to dry grass since any moisture will cause them to dissolve too quickly, defeating their purpose. Granular pre-emergent herbicides are most often used on established lawns that have already seeded themselves, or where the homeowner does not want a new growth of weeds. They can be put down before seeding your lawn as well. When using granular pre-emergents for lawn seeding, you should spread the granules in a pattern that is perpendicular to where your seed will be laid. This ensures that when new grass grows up through the pre-emergent, it will not block any of the chemicals from reaching and killing existing weed seeds. Granular pre-emergents release their chemical over time because they contain inert ingredients such as clay to provide slow release. They are therefore more expensive than liquid weed preventers, but are reusable -- simply water them down if they begin to dissolve too quickly. Regardless of which kind of pre-emergent herbicide you use, always read label instructions before application to ensure maximum results with minimum risk for yourself or your lawn.
Spring Pre-Emergent
Spring pre-emergent herbicide applications are made to lawns, turf sites and other non-crop areas. These products can be used to control many annual grassy and broadleaf weeds which could germinate from the soil over the winter period. Such species include: dandelions, chickweed, cutgrass or bent grass, henbit deadnettle, plantain and redroot pigweed. This application of herbicides needs to take place before these weed species emerge because it will have little effect on mature plants that have emerged from the soil already. This application of herbicides is best done during spring months as this is when most weed seeds would have germinated from the soil but before they develop into a fully mature plant. This prevents weed growth over the summer period and tillers, which are small weeds that arise from the roots of large weeds, from developing further in autumn so they can be more easily killed by pre-emergent herbicides before they produce seeds next spring. Pre-emergent herbicides should not be applied to lawns containing newly sown grass seed or recently established turf because it will prevent germination of weed seeds and cause damage to young plants. Also avoid spraying treated areas for a minimum period of 14 days to ensure that no damage occurs after a heavy rainfall event.
How Long Does Pre-Emergent Last?
Unfortunately this is not an exact science. Every type of pre-emerge product is different and designed for different climates, geographical areas, time of year purchased, etc. The average lifespan for most will range between 3 - 5 months once applied. However some can last up to 8 months or more depending on environmental factors such as amount of rain, type of soil it's in, etc.
Can I Use a Different Product to Extend Pre-Emergent?
It is generally not recommended that you mist a different product over the top of pre-emergent. This may help to prolong how long it lasts but will not help with effectiveness and will cause an issue for both your weed control and fertilizer applications later in the year when you want them applied!
How Long After Pre-Emergent Can I Seed?
Pre-emergents should be applied to your lawn before weed seeds germinate, therefore it is important that you do not apply a pre-emergent if there are plans to seed the area within 90 days of application. The pre-emergent herbicides must dissolve into the soil in order for them to work properly, and they can damage your new turf if applied incorrectly. If you plan on seeding after applying a pre-emergent, we suggest that you wait at least one month before doing so and then test an inconspicuous spot of sod with a soil test sample.
How to Apply Pre-Emergent
Everything considered
Pre-emergent is a fantastic product that has the potential to make your lawn look great in no time. Whether you are looking for an easier way to get rid of weeds, or simply want the best possible results when it comes to fertilizing and nourishing your land, pre-emergent can help in both cases! With these benefits combined with its long-lasting effects on soil health, this may be just what you need if you're not satisfied with how your yard looks now, because let’s face it, no one wants an ugly lawn!
