Weed and feed is a convenient combination of fertilizer and herbicide, designed to kill broadleaf weeds while supplying nutrients to the turf. This dual-action product requires precise timing to be effective, especially in Ohio, where cool-season grasses are common. Success depends on applying the correct herbicide component—pre-emergent or post-emergent—at the exact stage of the weed’s life cycle. Applying the product incorrectly can render the treatment ineffective or damage the lawn. This guide provides timing principles and application techniques for Ohio homeowners.
Understanding Weed and Feed Timing Principles
The efficacy of weed and feed is determined by the specific type of herbicide it contains. Pre-emergent herbicides create a chemical barrier in the soil that prevents weed seeds from germinating. This barrier must be established before the target weed’s seeds activate in the spring, making soil temperature the ultimate trigger for application timing.
Post-emergent herbicides are designed to kill weeds already visible above the soil line, such as dandelions or clover. These herbicides are most effective when absorbed through the leaves of actively growing weeds. Application should occur when both the grass and the weeds are in a vigorous growth phase, typically after early spring green-up.
For crabgrass, germination begins when the soil temperature consistently reaches 50 to 55 degrees Fahrenheit at a depth of two to three inches. If a pre-emergent product is applied too early, the chemical barrier may break down before the seeds are ready to sprout. If applied too late, the seeds will have already germinated, rendering the pre-emergent component useless.
Ohio Seasonal Application Schedule
The first necessary application in Ohio is the spring pre-emergent treatment aimed at crabgrass prevention. Since soil temperatures warm faster in Southern Ohio, this application window opens earlier, typically in mid-to-late March. In Northern Ohio, the soil warms more slowly, pushing the ideal application time toward mid-April.
A simpler, natural indicator is the blooming of the forsythia shrub, which often coincides with the soil temperature reaching the 50-degree Fahrenheit threshold. The goal is to apply the pre-emergent just as the forsythia flowers are dropping their petals, establishing the chemical barrier before the weed seeds begin to stir.
The second application uses a post-emergent herbicide, targeting broadleaf weeds like clover and dandelions that emerge later in the spring. This application is best performed when the weeds are small and actively growing, usually from late April through early June. The product must be applied when daytime air temperatures are consistently between 60 and 75 degrees Fahrenheit to ensure the weeds actively absorb the herbicide.
Fall application focuses primarily on the “feed” component to strengthen the lawn’s root system before winter dormancy. A late-season fertilizer application, often called a “winterizer,” should occur between late October and early November. This timing allows the cool-season grass to store carbohydrates in its roots, which improves spring green-up and overall resilience the following year.
Essential Application Techniques
Before applying granular weed and feed, the lawn should be mowed two to three days prior to the treatment. This allows the exposed leaf blades of the weeds to grow slightly, improving their ability to absorb the post-emergent herbicide. Leave the grass at its normal height, typically between 2.5 and 3.5 inches for cool-season varieties, to prevent undue stress.
Granular weed and feed products containing a post-emergent herbicide must be applied to a slightly damp lawn. The moisture allows the granules to stick to the foliage of the broadleaf weeds, ensuring the herbicide is absorbed. Avoid watering or mowing the lawn for 24 to 48 hours after application to give the herbicide time to work.
In contrast, a pre-emergent weed and feed must be watered into the soil to activate the chemical barrier. It should be watered with about a half-inch of irrigation within three days of application to dissolve the granules and move the product into the top layer of the soil. Always ensure the spreader setting matches the product and walk at a consistent pace to achieve uniform coverage and prevent fertilizer burn.
When to Avoid Using Weed and Feed
Applying weed and feed during high temperatures can severely damage the lawn. Avoid application when daytime temperatures consistently exceed 85 degrees Fahrenheit, which is common in Ohio summers. High heat stresses the cool-season grass, making it susceptible to chemical burn from the fertilizer component.
It is ineffective and potentially harmful to apply fertilizer when the lawn is dormant due to summer drought or extreme heat. Dormant grass cannot absorb the nutrients, leading to wasted product and increased risk of burn. Similarly, do not apply weed and feed immediately before or during a heavy rainstorm, as the product can be washed away into nearby storm drains or waterways, leading to environmental contamination.
Pre-emergent weed and feed should not be applied if you plan to overseed the lawn, as the herbicide will prevent the new grass seed from germinating. If seeding is necessary, wait at least 12 weeks after a spring application before planting new grass. Always sweep any stray granules off hard surfaces like driveways and sidewalks to prevent runoff and localized burning.