Weed and Feed is a multi-purpose lawn product, combining a fertilizer to nourish grass with an herbicide to control weeds. This dual-action approach simplifies lawn care, but its effectiveness hinges entirely on precise timing. The proper application window depends on two major biological factors: the temperature of the soil, which dictates weed germination, and the active growth cycle of the specific grass type. Applying this product at the wrong time can either waste the material, fail to control weeds, or damage the lawn.
The Critical Timing: Pre-Emergent Application
The most effective use of the weed control component is through a pre-emergent application, which targets weed seeds before they have a chance to sprout. This timing is determined not by the air temperature or the calendar date, but by the soil temperature. For pre-emergent herbicides to successfully prevent summer annual weeds like crabgrass and goosegrass, they must be applied before the soil temperature consistently reaches 55 degrees Fahrenheit at a depth of four inches.
In Georgia, this window varies significantly from south to north. Homeowners in South Georgia may need to apply their pre-emergent as early as late February or the first week of March. For Central Georgia, including the Atlanta area, the window shifts to mid-March, while North Georgia residents apply from mid-March to early April. Applying too late means the weed seeds have already germinated, rendering the pre-emergent barrier ineffective.
A second pre-emergent application is often necessary in the fall to prevent winter annual weeds, such as annual bluegrass and chickweed. This fall application should occur before soil temperatures drop below 70 degrees Fahrenheit, typically from mid-August to mid-September, with the North Georgia mountains starting earlier than the coast. This dual-season approach establishes two protective barriers, maximizing annual weed control.
Timing for Active Weeds: Post-Emergent Application
When weeds are already visible and actively growing, a post-emergent herbicide is required. This application is generally less preventative and more reactionary, working best when the target broadleaf weeds, such as dandelion and clover, are young. For the herbicide to be absorbed properly, the weeds must be healthy and not under stress from drought or extreme heat.
The ideal time for post-emergent application is during the late spring or early fall when temperatures are moderate. Applying the product when air temperatures are above 90 degrees Fahrenheit can cause the grass to become intolerant to the herbicide, leading to turf damage. The fertilizer component also requires the grass to be actively growing to utilize the nutrients and avoid injury.
Tailoring the Schedule to Georgia Grass Types
The “Feed” component of the product must be timed to coincide with the grass’s active growth period. This requirement creates a conflict with pre-emergent timing, especially for warm-season grasses. Warm-season grasses, which include Bermuda, Zoysia, and Centipede, are dormant during the early spring pre-emergent window.
For these grasses, fertilization should be delayed until the grass has fully emerged from dormancy and the soil temperature consistently reaches 65 degrees Fahrenheit, typically late April or early May. Applying a nitrogen-heavy Weed and Feed product too early to dormant warm-season turf can cause chemical burn and weaken the grass. Centipedegrass should only be fertilized once or twice during the summer growing season.
Cool-season grasses, such as Tall Fescue, have a different growth cycle and are primarily found in North Georgia. These grasses are actively growing in the early spring, making them the only turf type that aligns well with an early spring Weed and Feed application. Tall Fescue can be fertilized in early spring, around March or April, and again in the fall.
Application Best Practices and Follow-Up
Granular products work best when applied to a slightly moist lawn, allowing the herbicide granules to stick to the weed leaves for effective absorption. This moisture can be provided by morning dew or a light misting of water prior to application.
Application Rules
- Avoid mowing the lawn for at least two to four days after application.
- The herbicide requires 24 to 48 hours before it should be washed off by rain or watering.
- Do not apply Weed and Feed when air temperatures exceed 85 to 90 degrees Fahrenheit, as heat can stress the grass and increase the risk of chemical damage.
- Apply the product no more than twice per year, with a waiting period of at least six to eight weeks between treatments.
- Use a calibrated spreader and sweep up stray granules from sidewalks and driveways to prevent runoff.