When and How To Apply Weed and Feed in March April and May

If you had crabgrass last year, apply a combination product, like Scotts Turf Builder Halts Crabgrass Preventer or Sta Green Crab-Ex. Both contain a pre-emergent to control crabgrass.

Weed and feed fertilizer, especially for crabgrass control, begins in the spring. Feeding your lawn in the spring strengthens roots and gets it off to a good start before the heavy growing season. Lowes weed and feed products from Scotts and Sta Green,  can be applied in the spring months of March, April and May.

They include pre-emergent herbicides, post emergent weed and feed, and crabgrass control. You will also need to know if you have a cool season, warm season or transitional grass type.  Learn more about grass types here.

When To Apply Weed And Feed

The major grasses in warm season are bahiagrass, bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass.  Cool season grasses include Kentucky bluegrass, perennial ryegrass, tall fescue, and fine fescue.   Transition grasses is grown in those overlap areas like Kentucky, Tennessee, North Carolina.

Warm-season grasses do well due to the hot, dry summers, and some cool-season grasses, like fescue, because of the cold winters. Bermudagrass, centipedegrass, and zoysiagrass are the main warm-season grasses grown in the Transition Zone.

Lets Get Started With Weed and Feed Basics

  • Pre-emergents.  Like crabgrass preventer, work by stopping the seeds from germinating and must be applied early in the season.
  • Post-emergents. Like Weed & feed is designed to strengthen existing grass and kill off most weeds, like dandelions, at the same time.  It also improves your lawn’s ability to absorb water and nutrients. Weed and feed will generally have a high percentage of nitrogen to help “green up” your lawn. It also has a weed killer that will target broadleaf weeds like dandelions and many others.
  • Pre-emergents like Scotts Halts or Sta Green Crab Ex are not effective against weeds that have already begun to grow, so you must apply them before germination to gain any benefit. Crabgrass, the primary target of many lawn weed preventers, normally germinates just after forsythia blooms.
  • When you notice forsythia bushes blooming (March to early May, depending on your region), its time to apply a  crabgrass preventer.

The two main types of spring weed and feed are:

scottshalts21.  Weed and feed products for early spring usually contain pre-emergent herbicides.  They work by preventing weed seeds from sprouting, and they can be an effective way to control crabgrass and some broadleaf weeds. Except for crabgrass, most weeds don’t sprout in the early spring. They need the heat of late spring to early summer to begin growing.  Start with Scotts Halts Crabgrass Preventer or Sta-Green Crabgrass Crab-Ex Preventer and Fertilizer.

Apply in early spring to prevent crabgrass all season long. Most crabgrass preventers will also contain fertilizer so you are preventing weeds and giving your lawn its first application of fertilzer.

All fertilizers with crabgrass preventer are pre-emergent, which means they must be applied before the grass starts growing.

lowes sta green weed feed2. Other weed and feed products are designed for late-spring application and contain post emergent herbicides.  They contain herbicides designed to kill actively growing broadleaf weeds like dandelions.  This would include Scotts Turfbuilder with Plus 2, or Sta-Green Weed and Feed. These fertilizers can also be applied in the fall as weeds are storing up reserves for winter and moving nutrients from the leaves to the roots.  Weed and feed products will not stop crabgrass.

Spring time application of weed and feed strengthens the lawns roots and gets it off to a good start before the heavy growing season. If you had a crabgrass problem last year, apply a combination fertilizer with a pre-emergent to control it.  Used properly, weed killers are highly effective, but will fail when conditions aren’t optimal. For example, the granules of weed-and-feed products, must stick to the leaves of the weeds to be effective.

The perfect time to apply is early morning when there’s a heavy dew on the lawn.  If the grass isn’t wet, you’re just wasting time and money.  The weeds must be well wet and actively growing for the chemical to work.  Treating during a hot, dry spell in summer may yield disappointing results. Spring and fall, when temperatures are moderate and moisture plentiful, are ideal times.

Caution must be used when applying weed and feed on warm season grasses in southern states like Florida, Louisiana,  Texas, Georgia, South Carolina and surrounding areas.  Some weed & feed products can kill St. Augustine grass.

Find a weed and feed product formulated for the needs of St. Augustine grass, floratam, zoysiagrass, centipedegrass and carpetgrass lawns.  Scotts Bonus S Southern Weed & Feed and Sta-Green Southern Weed and Feed are both available at Lowes.  Here’s my article on southern lawns.

Crabgrass Control with Weed Preventers.  Pre Emergents
Pre-emergent herbicides, or weed preventers, control crabgrass and other weeds by stopping the seeds from germinating.  An application early in the growing season will give you a weed free lawn all summer.  Most crabgrass preventors will also help control goose grass, foxtail, dollarweed, creeping charlie, stinkgrass, yellow nutsedge, clover and spurge.

forsythiaWhen to Apply: Apply crabgrass preventer early in the season. This can be from mid-March to late April depending on the region and weather conditions.  As a general rule of thumb, it must be applied before your lawn starts growing or when the forsythia shrub blooms. Why forsythia?  Forsythia is the first plant that blooms each spring.  It is very recognizable by its gold leaves.

When forsythia blooms, it means temperatures are warm enough for grass to grow.  If the grass is growing, so is the crabgrass. And if the crabgrass is growing its too late to apply a pre-emergent.

Why timing matters: Weed preventers are not effective against weeds that have already begun to grow, so you must apply them before germination to gain any benefit. Crabgrass, the primary target of lawn weed preventers, germinates just as forsythia blooms, so take your cue from Mother Nature. When you notice forsythia blossoms in late March to early May, depending on your region, apply weed preventer. You will only have about a 3 week window each spring to apply.

Check your local soil temperature here.

Weed Control with Lowes Weed and Feed Products.  Post Emergent
Post-emergent herbicides, or weed control products control actively growing weeds.  These weed control products will not control or kill crabgrass. It is best to apply this herbicide as soon as you see signs of weed growth in late spring, generally from May to mid-June.

Apply a post-emergent weed and feed if the pre-emergent did not work, or if you did not apply a pre-emergent. Kills dandelions and other major lawn weeds like aster, buckhorn, thistle, chickweed, ground ivy, pigweed, ragweed,  wild carrot and yellow rocket.

When to Apply: Apply to grass when daytime temperatures are between 60°F-90°F anytime weeds are present and growing. Make sure that the grass is wet from dew or sprinkling before application. This helps particles adhere to weed leaves to produce best results. A spreader set to the indicated label setting is recommend for best results.  Do not apply if rain is expected within 24 hours.

Why timing matters:  Weed control in the product enters the weeds through the leaves and is taken to all parts of the weed including the roots. Then within a few days, the weeds will begin to wither and die.

After the Spring Application of Fertilizer

Always follow the directions on the package when applying fertilizer and lawn and garden chemicals.  An over application  of weed killer or fertilizer can damage desirable plants as well as the targeted weeds. Feeding your lawn just once a year will help improve its condition. Feeding it 4 times a year will make it a lot healthier.

Always allow 4-6 weeks in between applications. You can also use the summer holidays as a guideline by applying your second application of weed and feed on Memorial Day and your last application on Labor Day.  And you can use July 4th to apply an insect preventer only.

For more information, read our article on when to apply weed and feed for best results.

If you place your lawn on a regular feeding schedule, it can look lush and green.  When it comes to lawn care, many don’t know where to start.  Weed and feed fertilizers can be one of the most confusing lawn care products. Healthy lawns with a few patches of weeds do not need to be treated as much with a weed and feed product and can just be spot-treated for weeds.

The best way to control dandelions and other weeds in your yard is to grow a thick and green lawn.  Weeds will that take root wherever they can find the space and catch some sunlight. They stand little chance of growing in healthy grass. That’s why a sensible lawn care plan will help stop weed problems before they have a chance to start.

Applying A Summer Weed and Feed

Summer is tough on your lawn. Heat, foot traffic, and insects stress it out. Feeding your lawn in the summer protects and strengthens it against these problems, but use weed and feed cautiously.  If you don’t have a weed problem, we recommend using a product for insects like Scotts Summerguard or Ortho Bug B Gon.

Fall Weed and Feed Applications

Late summer to mid fall, treat your lawn with another round of weed and feed. The best fall option is one that has some phosphorus, which promotes root development and will help the grass bounce back in the spring. However, it may be difficult to find fertilizer with phosphorus, as many states have limited or banned phosphorus in fertilizers.  If that is the case in your area, try Scotts Fall Lawn food which is 32-0-12 or Sta Green Spring and Fall which is 28-0-04.

Update March 2015: The only fertilizer that Lowes carries that contains phosphorus is the Scotts and Sta Green Starter Fertilizers.  Analysis is 24-25-4 for Scotts and 18-24-06 for Sta Green. This is generally only used on new lawns to help establish the root system.  I have seen mixed results when used on existing lawns and would be cautious if using on your existing lawn.  It is high in nitrogen and phosphorus and could easily over fertilize your lawn.

Like all fertilizers, misuse can result in greater damage to your lawn. Weed and feed is a handy product for lawns that need added nutrition and weeds that need to be killed. However, not all weed and feed products will work for your lawn, and some are designed for specific regions of the country.

If you live in the southern states, you will probably need to use a regional or southern weed and feed to be used on St. Augustine grass,  floratam, centipede, zoysia, and carpet grass lawns.  Check the details on the weed and feed label to find the best product for your needs.

Ever wonder why you have crabgrass in summer even though you put down crabgrass preventer in spring? Most weed and crabgrass prevention problems relate to applying too late to prevent  crabgrass seeds from germinating. You have a short window to stop crabgrass before it starts.  In early spring, before the new seeds germinate, a pre-emergent  can be applied to the soil.  The result is less crabgrass grows during the season.  And, since less crabgrass grows, there are fewer plants next year.

Apply too early and  natural processes in the soil break down the herbicide. By the time it’s needed, much of the product has lost its potency. Apply too late and you’ve missed the early stage of germination when the herbicide works. There is nothing in preemergence herbicide that kills crabgrass seedlings once they’ve sprouted.  Back to timing… be sure to apply your preemergent weed control before crabgrass and other annual weeds germinate.

By Victoria Stone

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  1. Jerry March 23, 2016

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