Weeds are stubborn. Pull one today, and three pop up tomorrow. That’s because most lawn weed control fails by treating the surface, not the source. If you’re tired of fighting weeds on your own, contact Keystone Green Lawns today for a customized weed control plan and get a FREE ESTIMATE.
In this guide, we’ll cover the most common mistakes homeowners in Pennsylvania make, how to control weeds naturally, and when it’s time to use chemical treatments to keep your lawn healthy and weed-free.
Weed Identification.
You can’t control weeds if you don’t know what they are. Different weeds need different treatments, and using the wrong method can make the problem worse. The first step in any effective lawn weed control plan is simple: identify the type of weed you’re dealing with.
3 Main Types of Lawn Weeds
1. Broadleaf Weeds
These have wide, flat leaves and are easy to spot. Common ones include:
- Dandelion
- Clover
- Chickweed
- Plantain
These usually grow in thinner or stressed areas of your lawn and respond well to selective herbicides or manual removal.
2. Grassy Weeds
These look like grass but grow differently from your turf. Examples:
- Crabgrass
- Foxtail
- Annual bluegrass
They blend in easily and are harder to detect until they spread. Most grassy weeds require pre-emergent herbicides early in the season before they sprout.
3. Grass-Like Weeds
They look like grass but have tube-like or triangular stems. Examples:
- Nutsedge
- Wild onion
These weeds usually need a targeted herbicide. Regular weed killers often won’t touch them.
How to Identify Weeds in Your Lawn
- Step 1. Look at the leaf shape. Broadleaf weeds have wide, flat leaves (like clover or dandelion). Grassy weeds have narrow blades that resemble turf. Grass-like weeds (like nutsedge) have waxy, upright leaves.
- Step 2. Check the growth pattern. Does it grow in clumps, spread by runners, or pop up alone? Some weeds grow low and spread (creeping Charlie), others grow in clumps (crabgrass) or single stalks (dandelion). Growth style helps narrow down the type.
- Step 3: Time of year. Crabgrass thrives in summer, and chickweed in cool weather. The time of year you see the weed can help you identify it and apply treatments more effectively.
- Step 4. Examine the stem and root. Check the stem. Triangular stems point to nutsedge. Taproots (like dandelions) need full removal or they’ll grow back.
- Step 5. Take photos and compare them with online weed ID guides or better yet, use a lawn care app, or bring a sample to your local extension office or garden center for help.
Natural Weed Control Measures
You don’t always need to rely on chemicals to control weeds, especially if you’re proactive. Natural methods take more consistency but are safer for kids, pets, and the environment. Here’s what you can try to control your lawn weeds naturally:
1. Grow a Thicker Lawn
Weeds love bare spots and weak grass. The healthier and thicker your lawn is, the harder it is for weeds to break through.
- Mow high: Taller grass shades the soil, blocking weed seeds from getting sunlight. Keep your grass around 3–4 inches.
- Water deeply, not often: Shallow watering leads to shallow roots, which invite weed growth. Water once or twice a week, soaking the soil 6–8 inches deep.
- Overseed thin areas: Bare or patchy spots are open invitations for weeds. Overseed in the fall or spring to fill them in.
2. Hand Pulling
Still, the simplest and most effective option when done right.
- Pull weeds when the soil is moist (after rain or watering).
- Use a weed knife or trowel to loosen the soil and grab the root.
- Get the entire root, especially for taproot weeds like dandelions, or it’ll come back.
- It’s best for small lawns or spot weeding, not large-scale infestations.
3. Mulching
For garden beds and borders, not lawns.
- Apply 2–3 inches of organic mulch (like bark, wood chips, or straw) around plants.
- Mulch blocks sunlight and suppresses weed seeds.
- Don’t pile mulch against stems or tree trunks—it can trap moisture and cause rot.
- Mulch doesn’t work on grass, so don’t use it across your lawn.
4. Corn Gluten Meal
Corn gluten meal is a natural pre-emergent herbicide. It stops seeds from developing roots but doesn’t kill existing weeds.
- Works best on annual weeds like crabgrass.
- Must be applied before weed seeds germinate (early spring for crabgrass).
- Needs dry weather after application; rain can wash it away.
- Also adds nitrogen, so it helps fertilize your lawn too.
- Won’t work on perennials or well-established weeds.
5. Vinegar & Boiling Water
- Good for driveways, sidewalks, and gravel—not for lawns.
- Vinegar (acetic acid) burns leaves but won’t kill the roots. Most effective on small, young weeds.
- Boiling water kills everything it touches—use it on patios or cracks, not near grass or garden plants.
- These are non-selective and will harm anything green, so use with precision.
- Best for spot treatment in non-lawn areas.
6. Improve Soil Health
Healthy soil grows healthy grass, which naturally outcompetes weeds. Weeds often thrive in poor soil where grass struggles, so fix that first.
- Do a soil test to check pH and nutrient levels.
- Add compost to improve structure and microbial activity.
- Apply lime if the soil is too acidic, or sulfur if it’s too alkaline, based on test results.
- Fertilize based on what your lawn actually needs, not just a random mix from the store.
At Keystone, our Year-Round Lawn Care Program stops weeds before they start, without harming your lawn or the environment. Our approach uses targeted, low-impact treatments that are safe for kids, pets, and pollinators. If you have questions about our lawn care practices, our team is ready to answer your call. REQUEST A FREE LAWN ASSESSMENT HERE.
When to Use Chemical Weed Control
Sometimes, natural methods aren’t enough. If your lawn is overrun with weeds or you’ve tried pulling and overseeding without success, chemical weed control may be the best option.
When to Apply Weed Control to Your Lawn
- Widespread weed outbreaks: If your lawn is more weeds than grass, it’s time for stronger action.
- Persistent perennials: Weeds like nutsedge or bindweed have deep roots that keep coming back.
- Missed pre-emergent window: If you didn’t stop seeds early, post-emergent herbicides may be needed.
- Natural methods failed: If hand-pulling, overseeding, and soil fixes haven’t worked, it’s worth considering chemical support.
Choosing the Right Herbicides to Kill Weeds
There are two main categories of chemical weed killers: pre-emergent and post-emergent. Each works differently, and using the wrong type or using it at the wrong time won’t get you results.
1. Pre-Emergent Herbicides
Pre-emergents stop weed seeds from sprouting. They’re preventative, not curative, so timing is everything. Common active ingredients include prodiamine, dithiopyr, and pendimethalin.
- Best for: Preventing annual weeds like crabgrass, goosegrass, and annual bluegrass.
- When to apply: Early spring (before soil temps hit ~55°F) or early fall, depending on the target weed.
- How it works: Creates a barrier in the soil that disrupts seed germination. After spreading, water it right away to activate the barrier. If you wait too long, it won’t work.
- Important: It won’t kill existing weeds. Apply before you see them.
2. Post-Emergent Herbicides
Post-emergents are for weeds that are already up and growing. These come in two forms: selective and non-selective. Selective herbicides target specific types (broadleaf or grassy) without harming grass. Non-selective herbicides (like glyphosate) kill everything. It’s used only for spot treatment.
- Best for: Dandelions, clover, nutsedge, foxtail, and other visible weeds.
- When to apply: When weeds are actively growing—usually spring through fall.
- How it works: Spray when temps are between 60–85°F, no rain in the forecast, and minimal wind. Use a targeted nozzle to avoid overspray.
Common active ingredients:
- 2,4-D, Dicamba, MCPP – for broadleaf control
- Quinclorac – for crabgrass
- Sulfentrazone, Halosulfuron – for nutsedge
- Glyphosate – non-selective (total vegetation killer)
3. Systemic vs. Contact Herbicides
- Systemic: Absorbed into the plant and kills the root. Best for deep-rooted or perennial weeds like bindweed and nutsedge. Results take a few days to show.
- Contact: Kills only what it touches. It works fast but doesn’t affect the roots. It is good for small, young weeds or top-growth management.
4. Granular vs. Liquid Formulas
- Granular: Easier to apply with a spreader. Often used for pre-emergents or weed & feed combos. Needs watering to activate.
- Liquid: More precise and fast-acting. Best for post-emergent spot treatments. Use a pump sprayer or hose-end sprayer for targeted application, and follow label instructions to avoid harming your lawn.
How Much Does Lawn Weed Control Cost?
A professional lawn weed control service typically costs $50–$100 per visit, depending on your lawn size and the treatment used. Most companies offer seasonal programs (4–6 visits a year), which can range from $300 to $600 annually. This often includes pre- and post-emergent treatments and lawn fertilization.
Professional Weed Control for Lawns in PA
Still fighting the same weeds year after year? That’s a sign your lawn care plan isn’t working. At Keystone Green Lawns, we fix that. We don’t rely on generic products or broad solutions. We customize every treatment to what your lawn actually needs.
Get expert lawn weed control services in Pennsylvania. Call us to get a FREE, NO-OBLIGATION quote today. We serve customers in and around Pittsburg, PA, including Fox Chapel, Cranberry Township, Wexford, Sewickley, Franklin Park, Indiana Township, and Allison Park.