The best time to apply weed and feed is in the spring and/or fall when the temperature is just right. This is when grass is primed to absorb nutrients, and weeds are vulnerable to herbicides.
The perfect temperature to apply weed and feed is between 60 and 90 degrees. The ideal window of spring and fall weeks for applying weed and feeds will vary based on your grass type.
This article details when to apply weed and feed to your lawn, with expert insights.
When to Apply Weed and Feed by Region and Grass Type
The chart below details the approximate time intervals to apply a weed and feed with a post-emergent or a mix of post- and pre-emergent herbicides by grass zone.
Note: Ideal timing to apply a weed and feed varies based on your local climate. Ask your local Extension office specialists for the best month to apply weed and feed in your area.
| When to Apply Weed and Feed in Cool-Season Grass Regions | Spring: Mid-April to early June |
| Fall: Late August to mid-October | |
| When to Apply Weed and Feed in the Transition Zone | Spring: Cool-season grasses – Early April to mid-May Warm-season grasses – Mid-April to early June |
| Fall: Cool-season grasses – Mid-September to early November Warm-season grasses – September (before dormancy) | |
| When to Apply Weed and Feed in Warm-Season Grass Regions | Spring: March to early June |
| Fall: September through early October |
When to Apply Weed and Feed in the Fall
Fall is a good time to treat perennial weeds like dandelion and field bindweed, says Ron Honig, extension educator at the Kansas State University Extension. Why? As weeds store nutrients in their roots, they’ll also carry herbicides deeper through their structure. Use a weed and feed with only a post-emergent.
Early Fall
Choose a weed and feed that combines post-emergent with pre-emergent herbicides. Early fall is a good time to prevent winter annuals (e.g., poa annua, henbit) and cool-season perennials (dandelions) from germinating.
Ideal temperatures: Daily air temperature drops below 80 degrees.
From September to early October, lawns recover from the summer stresses of heat and drought. This is:
- The best time to feed cool-season grasses
- The last window for fertilizing warm-season grasses with nitrogen.
Note: For the pre-emergent to work, you need to apply the product when soil temperatures drop below 70 degrees (air temperature is below 80 degrees).
Late Fall
Ideal temperatures: Apply weed and feed only when daytime temperatures top 60 degrees.
By mid-October to early November, warm-season lawns are dormant or entering dormancy and should not be treated with a weed and feed. However, you might still have a small window to treat cool-season lawns in the transition zone.
Here’s what to do:
- Choose a fertilizer higher in potassium and lower in nitrogen (e.g., 15-5-10) to improve cold hardiness and avoid triggering a late green-up when the first frost is approaching.
Note: Applying nitrogen too late in the season can delay dormancy and expose the grass to early frost.
See Related:
— How to Apply Weed and Feed
— When to Water After Applying Weed and Feed
— Fertilizer Numbers: What They Mean and How to Use Them
When to Apply Weed and Feed in the Spring
If you live in the southern half of the country, you can start planning the weed and feed in late March or early April. The warm climate allows grass to green up early.
Note: According to University of Georgia experts, warm-season grasses have the highest risk of herbicide damage when transitioning from winter dormancy to active growth, so avoid applying weed and feed before the lawn greens-up in spring.
Early Spring
Ideal temperatures: Air temperatures above 60 degrees for at least 4 consecutive days.
Here’s what to do:
- Look for a weed and feed formula with post-emergent and pre-emergent herbicides (e.g., Scotts Turf Builder Bonus S Southern Weed & Feed2) so it can kill existing weeds and also prevent new weeds from growing.
- The best weed and feed is a low-nitrogen or slow-release product that doesn’t force leaf growth.
- Apply only when the grass is actively growing (after the second mow of the season).
Late Spring
Ideal temperatures: Daytime temperatures stay under 90 degrees (85 degrees for Bermuda).
Mid-April to early June is a good time to apply weed and feed on cool-season grasses in the northern half of the country.
- Avoid feeding Kentucky bluegrass, ryegrass, or fescues later than the first week of June to allow your cool-season lawn to enter summer dormancy.
- Potassium improves drought stress resistance. If a soil test indicates a deficiency, look for a weed and feed high in potassium, like The Andersons Premium Weed and Feed 24-0-16.
If you haven’t treated your warm-season lawn in March or early April, you can apply a weed and feed formula until early June. Warm-season grasses prepare for their peak growing season and welcome the added nutrients.
Best Time to Apply Weed and Feed Checklist
Here is a quick checklist noting the best season, temperature range, weather conditions, and best time of day to apply weed and feed.
| Best Season | Spring and/or fall |
| Ideal Temperature | Daytime temperatures consistently between 60 and 90 |
| Plant Activity | Grass is actively growing |
| Weather Conditions | Mild, windless day No rain in the 24- to 72-hour forecast (depending on product) |
| Best Time of Day | Early morning or early in the evening *If the product requires a wet application, the best time is early morning on a dewy lawn or after a light rain. |
| Newly Seeded Lawn | Wait until you mow at least 3 times (about 2 months). |
Why Weed and Feed Timing Can Be Tricky
Grass experts are not big fans of weed and feed products because they prevent optimal timing and dosage for the fertilizer and herbicide.
As Pawel Petelewicz, assistant professor in the Agronomy Department at the University of Florida, notes, the time gap is especially large for pre-emergent treatments.
“For example, in North Florida, the ideal timing for applying a pre-emergent herbicide is March 1, but the first recommended fertilizer application isn’t until April 15,” Petelewicz says.
You can get around this problem by:
- Applying a regular pre-emergent (like a crabgrass preventer) in early spring.
- Using a weed and feed with a post-emergent herbicide to kill any remaining weeds later in the season.
See Related:
— Is Weed and Feed Bad for Your Lawn?
— How Long After Applying Weed and Feed Can You Plant Seed?
Why You Shouldn’t Apply Weed and Feed in Summer
Summer is the worst time to apply weed and feed on your lawn because of high heat and drought. During this time, weeds and grass slow their growth, so herbicides and fertilizers are less effective and may even be harmful.
During summer:
- Weeds are less efficient in moving systemic herbicides inside their structure and are harder to kill.
- Turf is more sensitive to the salts in weed and feed and can suffer from fertilizer burn during drought times — many products are high in quick-release nitrogen.
FAQ About When to Apply a Weed and Feed
The benefits of applying a weed and feed on your lawn are:
• Thicker turf
• Healthier, more resilient grass
• Effective weed control
• Time-saving application (combines two lawn care tasks into one)
It’s too late for a spring application when midday temperatures rise above 90 degrees (85 degrees for Bermuda). In the fall, it’s too late to apply weed and feed when temperatures drop below 60 degrees; the date varies by location, but a good rule of thumb is to consider mid-October as the end of weed and feed season.
Yes, you can apply a weed and feed after a lot of rain, but you must wait until the lawn and soil dry out a bit. You want moist soil (not waterlogged) and damp grass leaves, so the weed killer granules can stick and dissolve without being washed out.
When to Hire a Lawn Treatment Professional
Timing a weed and feed application can be tricky, and these products work only if applied at the right moment. It’s easier and more effective to leave the scheduling to a lawn treatment professional.
Find a skilled lawn treatment pro near you with LawnStarter and reap all the benefits of weed and feed with zero effort from your part.
Sources:
- “It’s Warm Outside! Is it Time to Put Weed Control on my Lawn?” By Jeremy Kichler. University of Georgia.
- “Fall is the Best Time to Control Dandelions and Perennial Weeds.” By Ron Honig, extension educator. Kansas State Research and Extension.
- “Fall Lawn Weed Control.” By Paul O. Johnson, SDSU extension weed science coordinator. South Dakota State University Extension.
- Pawel Petelewicz, PhD., assistant professor in the Agronomy Department at the University of Florida, Gainesville, FL. Personal interview.
- “Temperature and Herbicide Application Questions.” North Dakota State University.
- “The Dilemma With Weed-and-Feed Lawn Products.” By Christopher Enroth, horticulture educator. University of Illinois.
- “Weed Control in Home Lawns.” By Patrick E McCullough, professor of Crop & Soil Sciences and Clint Waltz, extension specialist. University of Georgia.
Main Image Credit: Andrey Popov / Adobe Stock
