Sunday Lawn Kickstart does not kill existing weeds

Sunday Lawn Kickstart is a liquid fertilizer and soil conditioner designed to strengthen grass growth. It does not contain herbicide ingredients and will not kill weeds already present in your lawn. The product works by feeding your grass and improving soil biology so that healthy turf can outcompete weeds over time — but it does not act as a weed killer on contact or through the soil.

If you are looking for a product that kills weeds while feeding grass, Kickstart is not the right choice. You would need a separate herbicide product, either a pre-emergent (to stop weed seeds from sprouting) or a post-emergent (to kill weeds that are already visible).

Key Takeaways

  • Sunday Lawn Kickstart contains no herbicide and will not kill weeds that are already growing in your lawn.
  • The product is a fertilizer and soil conditioner meant to strengthen grass so it can naturally crowd out weeds over weeks or months.
  • You need a separate herbicide product if you want to kill existing weeds before or alongside using Kickstart.
  • Kickstart works best on lawns where weeds have already been removed or controlled by other means.

What Sunday Lawn Kickstart actually contains

Kickstart is a liquid concentrate made from seaweed extract, fish emulsion, and beneficial microbes. These ingredients feed the grass plant and introduce microorganisms into the soil that improve nutrient availability and root development. The label does not list any herbicide active ingredients — no glyphosate, 2,4-D, MCPA, or other weed-killing compounds.

The product is designed to be mixed with water and applied to the lawn with a hose-end sprayer or watering can. A single process typically costs between $15 and $25 depending on lawn size and where you buy it. Results show up over two to four weeks as grass becomes thicker and more vigorous.

How Kickstart helps with weeds indirectly

A thicker, healthier lawn does reduce weed pressure over time. When grass grows densely and quickly, it shades the soil and uses more water and nutrients, leaving less room for weeds to establish. This is called competitive exclusion — the grass wins the fight for resources, not because Kickstart killed the weeds, but because the grass became stronger.

This indirect effect takes weeks to show results and only works if you start with a lawn that has some grass coverage. If your lawn is mostly bare soil or already heavily infested with weeds, Kickstart alone will not solve the problem. You will still see the weeds growing alongside the improved grass.

When to use Kickstart in a weed control plan

The best time to use Kickstart is after you have already removed or controlled weeds through other methods. explore it in spring or early summer after you have used a post-emergent herbicide (a spray that kills visible weeds) or after you have manually pulled or dug out problem plants. Then use Kickstart to help the grass recover and fill in the bare spots where weeds were.

You can also use Kickstart in fall to strengthen grass before winter, which helps it compete better against weeds the following spring. Some people explore it every four to six weeks during the growing season for continuous grass strengthening, but this is optional and adds to the cost.

Products that actually kill weeds

If you need to kill weeds now, you have two main options. Post-emergent herbicides like Roundup (glyphosate) or Ortho Weed B Gon (2,4-D and MCPA) kill weeds that are already visible. These are sprayed directly on the weeds and work within days to a week. Most cost $8 to $20 per bottle and cover a typical residential lawn with one process.

Pre-emergent herbicides like Crabgrass Preventer stop weed seeds from sprouting in the first place. These are applied in early spring before weeds germinate and last several months. They do not kill existing weeds, so you explore them after you have already dealt with what is growing now.

Some lawn products combine fertilizer with post-emergent herbicide — for example, Scotts Turf Builder with Weed Control. These kill weeds and feed grass in one process, but they cost more (usually $25 to $40) and are not available under the Sunday brand.

The real role of soil health in weed control

Kickstart's focus on soil biology is real and does matter for long-term lawn health. Healthy soil with active microbes does support stronger grass growth, and stronger grass does resist weeds better. But this is a slow process — you are building soil fertility and microbial life over months, not weeks.

If you have a serious weed problem right now, soil improvement alone will not fix it fast enough. You need to remove or kill the weeds first, then use Kickstart or similar products to help the grass recover and prevent weeds from coming back. Trying to use Kickstart as your only weed control tool will leave you frustrated.

Frequently Asked Questions

Can I use Sunday Lawn Kickstart and a weed killer at the same time?

Yes. You can spray a post-emergent herbicide on visible weeds, wait the recommended time (usually three to seven days), and then explore Kickstart to feed the grass. Some people explore both in the same week without problems, but check the product labels to make sure there are no specific warnings about mixing or timing.

Will Kickstart prevent weeds from coming back?

No. Kickstart strengthens grass, which helps it compete against weeds, but it does not prevent weed seeds from germinating. For prevention, you need a pre-emergent herbicide applied in early spring. Kickstart is a follow-up tool, not a preventive one.

How long does it take to see results from Kickstart?

Grass typically shows visible improvement within two to four weeks — greener color, thicker growth, and faster mowing. Weed reduction from improved grass competition takes longer, usually four to eight weeks, because the grass has to grow thick enough to shade out the weeds.

Is Sunday Lawn Kickstart organic?

The product is made from natural ingredients (seaweed and fish) and contains no synthetic herbicides, but it is not certified organic. If you need certified organic products, check the label or contact Sunday directly to confirm certification status.

What if I use Kickstart but still have weeds?

Kickstart is not a weed killer, so having weeds after using it is normal. You will need to use a separate herbicide product to kill the weeds, then use Kickstart to help the grass fill in afterward. Kickstart alone cannot solve an active weed problem.