Overgrown lawns happen to everyone. Maybe you were away for a trip, or the weather simply didn’t cooperate. Before you know it, you’re facing knee-high grass.
Here’s the mistake most people make: They try to mow it all at once. That’s how you damage your lawn and ruin your mower.
Instead, trim the top layer with a string trimmer to about 6 inches, let it recover for 3-4 days, then mow gradually using the one-third rule. For grass taller than 12 inches, you’ll need multiple sessions spaced several days apart.
In this article, I’ll walk you through how to cut long grass step by step so you can bring your yard back under control without damaging it.
| Key Takeaways |
|---|
| • Never remove more than one-third of the grass height in a single cut • String trimmer first for any grass over 6 inches tall • Wait 3-4 days between cuts for grass recovery • Total time: 10-14 days from overgrown to maintained • Mow only when dry to avoid clogging and tearing |
| Difficulty: Moderate Estimated time to complete: 14 days or more (includes multiple mowing sessions and recovery time) Project cost: $50 to $100 (if you already have a mower, string trimmer, and leaf blower) |
What you need
Here are all the tools and equipment you need to get started:
- String trimmer
- Lawn mower (self-propelled or riding mower for large lawns)
- Bag attachment for mower (optional)
- Rake
- Wheelbarrow
- Edger
- Leaf blower
There are plenty of things lurking in the tall grass, from trash to critters, so make sure to wear safety gear:
- Protective goggles
- Ear protection
- Fully covered clothing
- High-top work boots
- Gloves
Step 1: Clear obstacles and check conditions
Walk through your lawn slowly. Remove rocks, branches, toys, and any debris.
Use a wheelbarrow to collect everything. Large objects destroy mower blades instantly.
Press your hand into the grass. If it feels damp, wait for it to dry. Mowing wet grass clogs your mower, tears grass instead of cutting cleanly, and creates ruts in muddy soil.
There might also be some critters, like voles or moles, hiding in the tall grass, so give wildlife time to relocate. Walk through the area, make noise, and wait 15-30 minutes before starting.
Read more: Why You Shouldn’t Mow Wet Grass
Step 2: Trim the top layer (first cut)
Don’t use your mower yet. If grass is over 6 inches, your mower will struggle or stall. Start with a string trimmer.
Dr. Michael Goatley, turfgrass extension specialist at Virginia Tech, says not to just cut the grass down to a few inches.
“If the grass is overgrown, you still should follow the one-third rule whenever possible. Scalping will make the grass more susceptible to environmental or pest stressors.”
For grass 12+ inches tall:
- Trim to 8-10 inches on the first pass. Work methodically with overlapping passes.
- Rake up all clippings. Thick layers smother the grass underneath.
- Water with 1 inch early morning (5-9 a.m.) or early evening (around 6 p.m.). Then wait 3-4 days before cutting again.
For grass 6-12 inches tall:
Trim to 6 inches. Rake, water, and wait 3-4 days before cutting.
Cutting without a mower:
String trimmers work for small to medium lawns. Grass shears with long handles handle small areas. For large areas, rent a brush cutter ($50-$75/day).
Read more:
- When Is the Best Time to Water Your Grass
- How Long Should You Water Your Lawn?
- What’s the One-Third Rule of Mowing
- Best String Trimmers
- What Is Scalping a LAwn and When Should You Do it?
Step 3: Second trim (if needed)
If grass was 15+ inches, you need another trim after recovery.
Reduce grass to about 6 inches. Rake clippings, apply 1 inch of water, and wait another 3-4 days.
Best times to cut: 8-10 a.m. or 4-6 p.m. Grass is dry and temperatures are moderate.
Step 4: First mowing pass
Your grass should be around 6 inches now. Time to mow.
I recommend using a self-propelled mower, as it’s easier to control, but you can use a riding mower too if your lawn is over 20,000 square feet.
Set your deck to 4 inches. Make sure your blade is sharp—dull blades tear grass and create brown tips.
Bag all clippings on this first cut. Leaving them creates thick mats that smother grass.
Mowing technique:
- Move slowly—3 mph max. Speed causes clogging and uneven cutting.
- Mow in a back-and-forth pattern. Overlap each pass by 3-4 inches.
- Listen to your mower. If the engine strains, you’re moving too fast.
- Apply 1 inch of water after mowing. Wait 3-4 days before cutting again.
Read more:
- How to Mow a Lawn the Right Way
- When is the Best Time to Mow Your Lawn?
- Self-Propelled vs Push Mowers
- What is a Self-Propelled Mower and How Does it Work?
- How to Sharpen Lawn Mower Blades
Step 5: Address weeds
When you leave your lawn unattended for weeks, you create an ideal environment for weeds to thrive. If there are only a few, hand-pull them from the roots.
If there are too many, apply a targeted herbicide directly to the weeds. Targeted herbicides kill the weeds without harming your grass. Follow the instructions on the label for mixing and application.
Let the herbicides work for at least a week. Once the weeds die, rake them up to make mowing easier.
Read related:
- Common Types of Weeds
- How to Identify and Control Grassy Weeds
- How to Get Rid of Weeds in Grass
- How to Apply Post-Emergent Herbicides
- Types of Post-Emergent Herbicides
Step 6: Progressive mowing to target height
Mow every 3-4 days, lowering your deck by half an inch to 1 inch each time. Always follow the one-third rule.
Each grass type has an ideal mowing height because of differences in leaf structure, growth habits, and stress tolerance.
| Grass | Season | Recommended mowing height |
| Fine fescue | Cool-season | 2.5 to 3.5 inches |
| Tall fescue | Cool-season | 3 to 4 inches |
| Kentucky bluegrass | Cool-season | 2.5 to 3.5 inches |
| Perennial ryegrass | Cool-season | 2 to 3 inches |
| Bermudagrass | Warm-season | 2 inches |
| St. Augustinegrass | Warm-season | 2.5 to 3 inches |
| Centipedegrass | Warm-season | 2 to 2.5 inches |
| Bahiagrass | Warm-season | 3 inches |
| Buffalograss | Warm-season | 2 inches |
| Zoysiagrass | Warm-season | 2 inches |
Change mowing direction each session. This encourages straight grass growth and prevents soil compaction.
Once you reach the target height, leave grass clippings on the lawn. They’re natural fertilizer.
Read more:
- An Ultimate Guide to Grass Types
- Guide to Warm-Season Grasses
- Guide to Cool-Season Grasses
- The Best Height to Cut Your Grass
- What Is Grasscycling?
- Ways To Use Grass Clippings as Mulch
Step 7: Edge the lawn and clean up
Use an edger or a string trimmer held vertically along sidewalks, driveways, and flower beds to trim excess grass blades.
Break up any large grass clumps with your rake. They’ll smother grass underneath.
Blow all clippings off hardscapes with a leaf blower. Grass on concrete stains and becomes slippery when wet.
Read more:
Best tools for tall grass
For moderate overgrowth (6-12 inches):
- Gas or battery string trimmer (25cc or 40V+)
- Self-propelled push mower
- Mower with 160cc+ engine
For severe overgrowth (12+ inches):
- Heavy-duty string trimmer or brush cutter (30cc+)
- Riding mower for large areas (20,000+ sq, ft,)
- Commercial walk-behind mower
Hand tools for small areas:
- Long-handled grass shears
- Traditional scythe
- Manual reel mower (only after grass is under 4 inches)
Don’t own the right equipment? Rent brush cutters or commercial mowers for $50-$100/day.
When to cut overgrown grass
Best season:
Cut during active growth periods when grass can recover quickly.
Cool-season grasses (fescue, bluegrass, ryegrass): Spring and fall when temperatures hit 60-75°F
Warm-season grasses (Bermuda, St. Augustine, Zoysia): Late spring through summer at 70-85°F
Avoid:
- Winter dormancy
- Extreme heat above 85°F
- Drought conditions
Best time of day:
- Early morning (8-10 a.m.) after dew dries
- Late afternoon (4-6 p.m.)
- Never noon to 3 p.m.— too hot
How to cut 3-foot tall grass
Grass at 3 feet (36 inches) requires patience. Plan for 2-3 weeks minimum.
Week 1, Day 1: Trim from 36 inches to 12 inches. Rake, water, wait 4 days.
Week 1, Day 5: Trim from 12 inches to 6 inches. Rake, water, wait 4 days.
Week 2, Day 2: First mow at 4 inches. Bag clippings. Water, wait 3-4 days.
Week 2, Day 6: Mow at 3 inches (or target height). Continue every 3-4 days until you reach ideal height.
Total timeline: 14-21 days from start to finish.
FAQs on cutting tall grass
No. Grass over 6 inches should be trimmed first. Most residential mowers lack power for tall grass and will stall or sustain damage.
Scalping weakens grass, making it vulnerable to disease, weeds, and heat damage. Recovery takes 4-6 weeks or longer.
Every 3-4 days during recovery. Return to weekly mowing once grass reaches target height.
Yes, if done improperly. It can bend blades, clog the deck, overheat the engine, or damage belts. Always trim with a string trimmer first.
No. Manual reel mowers only work on grass 3 inches or shorter. Use a string trimmer and powered mower for overgrown lawns.
When to hire a professional
Consider professional help if:
- Grass has been neglected for months
- Grass exceeds 2 feet across large areas
- You lack appropriate equipment
- Physical limitations prevent safe operation
- You’re uncertain about grass type or technique
Professional lawn care companies have commercial-grade brush cutters, heavy-duty mowers, and proper disposal capabilities. They can complete in one day what takes homeowners multiple weekends.
Lawn Love pros handle overgrown lawns step by step, following proper recovery protocols. Our services include mowing, trimming, edging, aeration, fertilization, and weed control to get your lawn back on track.
Main Image: Man cutting grass using string grass trimmer. Image Credit: zphoto83 / Adobe Stock
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