How To Use Weed And Seed

When to apply pre-emergent? This is one of the most frequent questions you hear each spring. Here's what you need to know! Weed & Feed Application Instructions. A fertilizer and herbicide combination better known as "weed and feed" is applied to the entire lawn, regardless of the number of weeds and where they are located. While fertilizer contains nitrogen, phosphorus and potassium, the herbicide is a toxic substance designed …

Solved! When to Apply Pre-Emergent to Prevent a Weedy Lawn and Garden

Stop weeds before they get a foothold by applying a pre-emergent herbicide at the right time.

By Glenda Taylor | Updated Oct 25, 2021 11:04 AM

Q: When should I apply pre-emergent weed control?

A: Knowing when to apply pre-emergent herbicide can mean the difference between having a lush, weed-free lawn or a yard riddled with dandelions and other unwanted plants.

Pre-emergent weed killers fit into a particular group of herbicides that don’t kill unwanted plants. Instead, they stop the seeds of unwanted plants from sprouting in the first place. Various pre-emergent products are available for lawns, vegetable gardens, and flower beds. However, applying them too early can keep beneficial seeds from sprouting, and applying them too late won’t do any good. Ahead, learn when to use pre-emergent and when not to.

Early spring and fall are the most effective times to apply pre-emergent herbicides.

Applying a pre-emergent herbicide will prevent seeds from sprouting, but the most effective times to use it are in the spring and again in the fall.

  • Early spring application: By treating lawns and perennial flower beds in early spring, gardeners can drastically reduce the number of annual summer weeds such as crabgrass, foxtail, and sandbur, which germinate in late spring. However, this is not the time to treat the soil in a garden or annual flower bed where beneficial seeds, such as flowers, corn, cucumbers, or squash, will be sown. Pre-emergents don’t keep just unwanted seeds from sprouting—they keep all seeds from germinating, so hold off on using the product in a garden or flower bed until the desired plants sprout and begin to grow.
  • Fall application: A lawn might appear virtually weed-free going into fall but then weeds suddenly appear. The pre-emergent applied in spring is no longer protecting the yard by this time, and a few invasive weed seed varieties, such as henbit and chickweed, are lying in wait for cooler temps before sprouting. After sprouting, these hardy weeds will remain small, perhaps even unnoticeable, throughout the winter. Still, next year, they’ll revive in spring and grow with a vengeance. By then, it’s too late to use a pre-emergent—a post-emergent herbicide is necessary at that point.
See also  Exotic Weed Runtz Seeds

Some jobs are better left to the pros. Receive free, no-commitment estimate from licensed lawn service professionals near you.

Apply spring pre-emergent when the soil temperature is around 55 degrees or above.

Rather than setting a specific date for applying a pre-emergent, a good rule of thumb is to use pre-emergent when spring soil temperatures are around 55 degrees for at least 48 hours. Directions don’t always apply, because the climate varies from region to region. In southern USDA growing zones, such as Louisiana, this means around the first of March, while the temps will be more conducive to applying a pre-emergent in North Dakota when June arrives.

In the fall, it’s also a good idea to apply a pre-emergent when the soil temp cools to around 55 degrees. This usually corresponds with daytime temperatures that range from the mid-60s to the mid-70s, indicating the soil is cooling to the temps at which cold weather seeds prepare to sprout.

Granules or liquid formulations are the two primary types of pre-emergent herbicides.

Both types of pre-emergent herbicides, liquid and granular, work in the same way to keep weed seeds from sprouting, and choosing one is often more about personal preference.

  • Liquid: Easy to apply with a pump-type garden sprayer, liquid pre-emergent herbicides are available either in full-strength products or as concentrates that require diluting in water before using.
  • Granular: Resembling tiny grains, granular pre-emergent products are applied using a drop spreader, a broadcast spreader, or even by shaking the granules onto the soil with a cup. Using a spreader works best for even coverage on large areas, such as lawns. Still, gardeners might prefer sprinkling the granules around established plants in a vegetable or flower garden using a cup, and then working the granules into the soil’s surface.
See also  How Long Do Weed Seeds Stay Good

Reseeding a lawn too soon after applying a pre-emergent herbicide may keep the grass seeds from sprouting.

A typical step in keeping a lawn lush involves reseeding in late spring or early summer to add more grass to the turf and create a denser yard. Unfortunately, overseeding while a pre-emergent herbicide is still effective will prevent the grass seeds from sprouting. When overseeding, wait a minimum of 8 weeks after applying a pre-emergent.

If waiting isn’t an option because the grass species, such as fescue, needs cooler temps to sprout, consider skipping the fall application of pre-emergent and overseed the lawn at that time instead. This might result in needing to apply both a pre-emergent in early spring of the following year, followed by a post-emergent lawn herbicide a few weeks later to control both weed seeds and weeds that might have germinated over the winter.

Some jobs are better left to the pros. Receive free, no-commitment estimate from licensed lawn service professionals near you.

Weed & Feed Application Instructions

A fertilizer and herbicide combination better known as “weed and feed” is applied to the entire lawn, regardless of the number of weeds and where they are located. While fertilizer contains nitrogen, phosphorus and potassium, the herbicide is a toxic substance designed to kill the existing weeds while preventing new ones from growing. This combination is available in pellets, powder and liquid form. It is most often applied any time weeds are visible and generally lasts for up to six weeks.

Details and Usage

Weed and feed formulas is applied to a wet lawn and the lawn is not mowed or watered for at least 24 hours. Application is best in spring or fall when the weeds are actively growing. It is not applied to lawns that are near water supplies, storm drains or drainage ditches. Most weed and feed combos actively kill dandelions and other major weeds that have strong, deep root systems. Each weed and feed package provides a list of exactly what plants it kills, along with application and frequency instructions.

See also  Weed And Seed

Herbicides in Weed and Feed

Weed control products are available in several forms: selective, non-selective, contact and systemic. Selective herbicides knock down certain weed species without affecting the growth of other plants and most weed and feed combinations contain selective herbicides. Non-selective herbicides wipe out everything it touches. Contact herbicides will also kill plants on contact, but often leave the rhizomes intact to re-grow later. Systemic herbicides are absorbed and spread throughout the plant, killing it completely. Knowing what weeds you have is helpful when selecting the correct herbicides in your weed and feed product.

Fertilizers in Weed and Feed

Fertilizers are vitamins for your lawn and when properly applied, will enhance the look and growth of your grass or plants. Slow-release fertilizers feed plants gradually over a certain period. The essential elements of fertilizer are nitrogen, phosphorus and potassium, or N-P-K. Nitrogen promotes the green color and can be fast-acting, slow release or both. Phosphorus promotes root growth, while potassium helps the grass survive temperature extremes. Knowing your soil condition is helpful when selecting the correct fertilizer needed. A soil test kit, available at most large garden centers, can give you this information.

Weed and Feed Combinations

Weed and Feed products contain slow-release water soluble mixtures of dry lawn fertilizer and selective slow-release weed control formulas. Weed and feed is most often used on established lawns, as this mixture can easily overwhelm young grass. Weed and feed products should only be used when you actually have a weed problem, otherwise a fertilizer is all you need.