May in Texas is the last call before summer arrives in full force. By June, temperatures will be punishing, water restrictions may kick in, and your lawn will be locked into whatever condition you’ve set it up for. That makes May the single most important month for Texas lawn care—the window where smart action pays the biggest dividends. Here’s exactly what to do, week by week, to send your lawn into summer strong.

Why May Is the Critical Month

Warm-season grasses—Bermuda, St. Augustine, Zoysia, and Buffalo—are now in peak growth mode. Soil temperatures are solidly above 65°F, root systems are expanding rapidly, and the grass is hungry for nutrients. At the same time, weeds are germinating, pests are waking up, and the sun is getting intense. Everything is accelerating, and your lawn needs you to keep pace.

The decisions you make in May echo through September. A well-fed, properly watered, correctly mowed lawn in May becomes a resilient one in August. A neglected one becomes a brown, weedy mess that takes months to recover.

Week-by-Week May Lawn Calendar

Week 1 (Early May): Assess and Plan

Walk your entire yard and note:

  • Bare or thin patches from winter dormancy that haven’t filled in
  • Weed pressure — are you seeing crabgrass, dandelions, or dollarweed?
  • Irrigation coverage — run each zone and check for dry spots, broken heads, or uneven spray patterns
  • Pest signs — chinch bug damage (yellowing patches in St. Augustine near hot surfaces), fire ant mounds, armyworm chewing

This 20-minute walkthrough shapes your entire May game plan.

Week 2 (Mid-May): Fertilize

This is the prime fertilization window for warm-season Texas grasses. Here’s what to apply:

  • Slow-release nitrogen fertilizer at a rate of 1 lb of nitrogen per 1,000 sq ft. Look for a 15-5-10 or similar 3-1-2 ratio product.
  • Iron supplement if your lawn looks yellow-green despite adequate nitrogen. Texas alkaline soils (pH 7.5–8.5) lock up iron, and a foliar iron spray or granular iron sulfate greens things up fast without pushing excessive growth.
  • Skip phosphorus unless a soil test specifically shows a deficiency—most established Texas lawns have plenty.

Apply fertilizer to dry grass, then water it in with about ¼ inch of irrigation. Avoid fertilizing before heavy rain—the product will wash into storm drains.

Week 3 (Late May): Weed Control

By late May, you can see which weeds escaped your pre-emergent application (or remind yourself to apply pre-emergent earlier next year). For existing weeds:

  • Broadleaf weeds (dandelions, clover, henbit): Spot-treat with a selective post-emergent herbicide. Apply on a calm morning when temperatures are below 85°F to avoid damaging your grass.
  • Grassy weeds (crabgrass, dallisgrass): These are harder to control selectively. Hand-pull small patches; for large infestations, consult a local lawn care professional about targeted herbicides.
  • Dollarweed/pennywort: Usually a sign of overwatering. Reduce irrigation frequency before reaching for chemicals.

Important: Never apply broadleaf herbicide to the entire lawn in temperatures above 90°F. The combination of heat stress and herbicide stress can seriously damage even healthy turf.

Week 4 (End of May): Final Prep Before Summer

  • Raise mowing height by ½ inch from your current setting to prepare for summer heat
  • Check mulch depth in garden beds adjacent to the lawn—3 inches of mulch reduces heat radiation onto turf edges
  • Ensure your irrigation controller is set to summer schedule (see watering section below)
  • Apply a second round of fire ant bait if mounds are still appearing

Mowing: The Most Important Thing You Do

Mowing isn’t just maintenance—it’s the most frequent and impactful lawn care activity you perform. Getting it right in May sets your lawn up for summer success.

Correct Heights by Grass Type

  • Bermuda: 1.5–2 inches (common Bermuda); 0.5–1.5 inches (hybrid Bermuda with reel mower)
  • St. Augustine: 3–3.5 inches — this grass needs height for shade and moisture retention
  • Zoysia: 1.5–2.5 inches
  • Buffalo grass: 3–4 inches

Mowing Best Practices

  • Never remove more than one-third of the blade height at once. If your grass is 4 inches and target is 3, mow to 3—don’t jump from 6 to 3.
  • Mulch your clippings — they decompose fast in Texas heat and return nitrogen to the soil. It’s like a free light fertilization every mow.
  • Sharpen blades monthly during peak growing season. Dull blades tear grass, causing brown tips and increased disease risk.
  • Alternate mowing patterns each session to prevent soil compaction and grass grain.
  • Mow in the evening during hot weather—fresh-cut grass loses moisture, and you don’t want that happening under the midday sun.

In May, you’ll likely be mowing every 5–7 days for Bermuda and St. Augustine. By June, Bermuda may need mowing every 4–5 days.

Watering: Train Your Lawn for Summer

The goal of May watering is to transition your lawn from spring’s cooler, moister conditions to summer’s hot, dry reality. You want deep roots, not shallow dependence on daily sprinkles.

The Deep-and-Infrequent Method

  • Water 1 inch per week total (including any rain)
  • Apply in 2 sessions — for example, ½ inch on Tuesday and ½ inch on Friday
  • Water early morning (4 AM–8 AM) to minimize evaporation and reduce disease risk from overnight moisture
  • Use the catch-can test — place 5–6 empty tuna cans around your yard and run your sprinklers. Measure the water in each can after a session to verify uniformity and volume.

Signs Your Lawn Needs Water

  • Grass blades fold in half lengthwise (especially visible in St. Augustine)
  • Footprints remain visible for more than a few seconds after walking across the lawn
  • Grass takes on a blue-gray color instead of bright green

When you see these signs, water within 24 hours. But don’t panic-water every day—that creates shallow roots and invites fungal disease.

For a deeper dive on irrigation, our post on smart irrigation strategies by region covers advanced approaches.

Pest Watch: What’s Active in May

Texas lawns face a lineup of pests that become active in May:

  • Chinch bugs: The #1 St. Augustine pest. Look for yellowing patches that start near hot, sunny edges (driveways, sidewalks). Part the grass in the transition zone between healthy and damaged areas—you’ll see small black-and-white insects scurrying away.
  • Grubs: White C-shaped larvae of June bugs feed on grass roots. Pull back turf in suspicious areas; more than 5 per square foot warrants treatment with a granular insecticide.
  • Fire ants: Broadcast bait across your entire yard once in May and once in fall for season-long control. Drench individual mounds that appear between broadcast treatments.
  • Armyworms: Watch for rapidly expanding brown areas and small green caterpillars on the grass blades, especially after rainy periods.

For more on Texas pest management, check our guide to lawn watering and pest control in early summer Texas.

Filling In Bare Spots

If you have areas that didn’t recover from winter dormancy:

  • Bermuda and Buffalo grass: These spread aggressively on their own given adequate water and nutrients. Encourage lateral growth by keeping these areas well-watered and fertilized. Bermuda fills in remarkably fast in May—often 2–3 inches of lateral growth per week.
  • St. Augustine: Doesn’t come from seed reliably. Buy sod plugs or full sod pieces and plant them 12 inches apart. They’ll fill in within 6–8 weeks.
  • Zoysia: Slow to spread. Sod plugs work but expect 2–3 months for full coverage.

May Soil Care

If you haven’t had a soil test in the past two years, now’s a great time. Texas A&M AgriLife Extension offers comprehensive testing for about $12. The results tell you exactly what your soil needs—no more guessing at fertilizer ratios.

If your soil is compacted (common in new-construction homes with builder-grade clay), core aerate now. Warm-season grasses recover quickly from aeration during their peak growth period, and the improved root zone access pays dividends all summer.

Looking Ahead: The Summer Plan

Map out your next few months:

  • June: Monitor irrigation, scout for pests biweekly, mow on schedule
  • July: Light fertilization (½ lb nitrogen per 1,000 sq ft), watch for brown patch in St. Augustine
  • August: Maintain mowing and watering, begin thinking about fall transition
  • September: See our guide on transitioning your Texas lawn from summer to fall

Get the Full Texas Lawn Playbook

May is just one month in a year-round commitment to a great-looking Texas lawn. If you want the complete picture—every month, every grass type, every region of Texas—Lush Lawns gives you everything in one place. It’s the practical, no-nonsense guide for homeowners who want results without wasting time or money.

Your lawn is growing fast right now. Match its energy, and you’ll love what you see all summer.