Weed Control · Hawaii
Dollarweed: The Weed That Tells You About Your Water in Hawaii
UF calls dollarweed a reliable indicator of wet environments. Clemson's first control step is not a herbicide — it is checking how often you irrigate.
Regional Hub
Hawaii Lawn Care
Lawn care built for Hawaii: Bermuda maintenance, regional weed and disease control, and a season-by-season calendar for USDA zones 9a–13a.
Dominant Grass
Bermuda
USDA Zones
9a–13a
Soil
Volcanic soils throughout, of two very different kinds: Andisols formed in ash on the younger slopes (Hilo, the state soil, is one and covers about 21,000 acres of prime ground) and highly weathered Oxisols on the old windward slopes
Humidity
Humid year-round on the windward sides, drier on the leeward, with trade winds rather than seasons doing the work — and no winter dormancy at all, so growth and mowing never stop
Weed Control in Hawaii
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Weed Control · Hawaii
Dallisgrass vs Crabgrass: One Comes Back Every Year in Hawaii
Dallisgrass and crabgrass look alike and need opposite strategies: crabgrass dies at frost, dallisgrass comes back from the same crown for years.
Weed Control · Hawaii
How to Get Rid of Crabgrass: Timing Beats Chemicals in Hawaii
Crabgrass is a timing problem — but one pre-emergent pass is not a whole season. UF/IFAS: season-long control takes a second application 6–9 weeks later.
Weed Control · Hawaii
How to Get Rid of Nutsedge: One Pull Does Nothing in Hawaii
Nutsedge ignores ordinary weed killer because it is a sedge. UC IPM: one pull does nothing — but pulling every 2 to 3 weeks drains the tuber underneath it.
Weed Control · Hawaii
Kill Dandelions Without Killing Grass — For Good in Hawaii
Killing dandelions without killing grass comes down to the taproot: the selective herbicides that reach it, and the month they actually work.
Weed Control · Hawaii
Spring Weed Control: Soil Temp, Not the Calendar in Hawaii
Spring weed control is decided by soil temperature, not the calendar — a pre-emergent applied two weeks late does nothing at all. The trigger, and the plan.
Lawn Diseases in Hawaii
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Lawn Diseases · Hawaii
Lawn Disease After Flooding: What Follows the Water in Hawaii
Flooding moves the pathogen, stresses the plant and leaves the leaf wet. The hour thresholds that trigger Pythium and brown patch, and why nitrogen cuts both ways.
Lawn Diseases · Hawaii
Dollar Spot Treatment: The Disease Nitrogen Fixes in Hawaii
Dollar spot is the one lawn disease caused by too little nitrogen, not too much — the exception to every other fungus guide here. The hourglass lesion confirms it.
Lawn Diseases · Hawaii
Armyworms and Sod Webworms: Which Ate Your Lawn? in Hawaii
Green to brown in two days means armyworms; closely cropped patches mean sod webworms. Both are caterpillars — which rules out most grub products.
Lawn Diseases · Hawaii
Chinch Bugs: How to Confirm Them and What Kills Them in Hawaii
Chinch bugs: two species, two grass families, and a float test that confirms them in five minutes. Plus the documented resistance nobody prints on the bottle.
Lawn Diseases · Hawaii
Fire Ants in Lawns: Kill the Colony, Not the Mound in Hawaii
Treating fire ants in lawns by drenching the mound kills workers and moves the colony. Bait reaches the queen — that difference is why most attempts fail.
Lawn Diseases · Hawaii
Lawn Grubs: How and When to Kill Them in Hawaii
Most lawns never reach the grub treatment threshold, so count before you buy — and curative products only work from August through October.
Lawn Diseases · Hawaii
Brown Patch Treatment: Fungicide Alone Won't Fix It in Hawaii
Brown patch treatment needs two things: the right fungicide, and the summer nitrogen habit that caused it. Fungicide alone buys you a repeat next July.
Grass Types in Hawaii
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Grass Types · Hawaii
Centipede Grass Lawn Care: Dark Green Is a Symptom in Hawaii
UGA lists dark green foliage as a symptom of centipedegrass decline. The colour most people are aiming for is the first sign this grass is failing.
Grass Types · Hawaii
Perennial Ryegrass: The Fastest Grass, and Its Price in Hawaii
Penn State: it germinates in 5 to 7 days and is very competitive with other turfgrasses. Both halves decide what care this lawn costs you.
Grass Types · Hawaii
Zoysia Grass Care: The Grass Nobody Defaults To in Hawaii
Zoysia is a secondary grass in 25 states and the dominant one in none. You choose it deliberately — and three of its costs are never on the sod invoice.
Grass Types · Hawaii
Growing Grass in Shade: The Two-Hour Minimum in Hawaii
Growing grass in shade has a hard floor: fine fescue is the most shade-tolerant lawn grass and still needs two hours of direct sun. Below that, no seed works.
Grass Types · Hawaii
Bermuda Grass Care: Mow It Lower Than You Think in Hawaii
Bermuda grass care starts with mowing lower than feels right — 1 to 2 inches. Plus when to scalp, how much nitrogen it takes, and the schedule that works.
Grass Types · Hawaii
St. Augustine Care: Mow High, Watch for Chinch Bugs in Hawaii
St. Augustine grass care: mow high, watch for chinch bugs, and know it cannot be seeded — only sod, plugs or sprigs. Plus the herbicides that damage it.
Grass Types · Hawaii
St. Augustine vs Zoysia: Shade or Traffic Decides in Hawaii
St. Augustine vs zoysia comes down to two questions: how much shade, and how much foot traffic. One tolerates each — and they are not the same grass.
Fertilizer in Hawaii
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Fertilizer · Hawaii
Winterizer Fertilizer: Right Idea, Wrong Bag in Hawaii
Purdue backs late-fall nitrogen and faults the bags: rates run too low, the potassium needs a soil test to justify — and warm-season lawns should skip it entirely.
Fertilizer · Hawaii
Lawn Soil pH: When to Lime, When to Add Sulfur in Hawaii
Lawn soil pH decides whether lime or sulfur is the fix — and the right answer inverts between Georgia and Arizona. What the soil test number means.
Fertilizer · Hawaii
When to Weed and Feed: Two Bags Often Beat One in Hawaii
Weed and feed does two jobs on two different calendars, so one bag rarely times both right. The month it works, and the lawns the label forbids.
Fertilizer · Hawaii
When to Fertilize: Autumn Matters More Than Spring in Hawaii
When to fertilize a lawn: autumn matters more than spring for cool-season grass, the reverse for warm-season — plus the state laws that close the window.
Fertilizer · Hawaii
Why Is My Lawn Yellow? 9 Causes, Not Just Nitrogen in Hawaii
Your lawn is yellow and nitrogen is only one of nine causes — feeding the wrong one wastes a season. Diagnose by pattern, blade and timing first.
Lawn Care Guides in Hawaii
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Lawn Care Guides · Hawaii
Lawn Recovery After Flooding: The Clock Starts Underwater in Hawaii
How long turf survives underwater, why the damage shows up days later, the 1-inch silt rule, and the survival percentage at which replanting beats rescuing.
Lawn Care Guides · Hawaii
Lawn Ruts After Storm Cleanup: What Repairs, What Doesn't in Hawaii
Shallow ruts take a ¼-inch topdressing; deep subsoil compaction from heavy equipment on saturated ground is, in Penn State's words, practically permanent.
Lawn Care Guides · Hawaii
Waterlogged Lawn: Test It Before You Fix It in Hawaii
Water standing after every rain has four possible causes and they need different fixes. A 15-minute hole test tells you which one you have before you spend money.
Lawn Care Guides · Hawaii
When to Stop Mowing the Lawn: Watch 50°F, Not the Calendar in Hawaii
Cool-season grass stops growing when daytime highs stay below 50°F — that's the last-mow trigger. Too tall into winter invites disease; scalping is worse.
Lawn Care Guides · Hawaii
Winter Lawn Care: The Damage Happens in February in Hawaii
Penn State: crown hydration is the most common and destructive winter injury, and it happens in late winter after thawing and freezing — not in the deep cold.
Lawn Care Guides · Hawaii
Summer Lawn Care: What Helps and What Hurts in Hawaii
Summer lawn care inverts by grass type: feeding a warm-season lawn is routine; feeding a cool-season lawn is the classic mistake.
Lawn Care Guides · Hawaii
Fall Lawn Care: What to Do, and in What Order in Hawaii
Fall lawn care is the one season when doing more genuinely pays — for cool-season grass. On a warm-season lawn, autumn is mostly about stopping.
Lawn Care Guides · Hawaii
How to Aerate a Lawn: Spike Tools Make It Worse in Hawaii
How to aerate a lawn, and when not to: spike tools compact the soil they punch through, core aeration pulls plugs out, and most lawns need it rarely.
Lawn Care Guides · Hawaii
How to Fix Bare Spots in a Lawn — Or Leave Them in Hawaii
A bare spot smaller than your fist closes on its own. The bigger ones are a symptom — and the shape of the spot tells you which cause to fix first.
Lawn Care Guides · Hawaii
Lawn Mowing Height: Your Deck Setting Is Lying in Hawaii
Your deck setting is not your lawn mowing height — measure it once and most people find they cut lower than they think. The real number by species.
Lawn Care Guides · Hawaii
Should You Bag Grass Clippings? It Costs Nitrogen in Hawaii
Bagging grass clippings throws away up to a quarter of your lawn's nitrogen — and clippings do not cause thatch. The three times bagging is still right.
Lawn Care Guides · Hawaii
Spring Lawn Care: Do Less, and Do It Later in Hawaii
Most spring lawn damage is done in March by people being helpful. Spring lawn care runs on soil temperature, not the calendar — and the order matters.
Lawn Care Guides · Hawaii
When to Overseed Your Lawn — and When Not to Bother in Hawaii
When to overseed: late summer beats spring for cool-season lawns, most warm-season lawns should not be overseeded at all — and pre-emergent blocks your seed.
Lawn Care Guides · Hawaii
How Often to Water Your Lawn: Twice Beats Daily in Hawaii
How often to water a lawn: twice a week beats every morning, and one inch a week beats guessing. Measure your own sprinkler — the timer is not telling you.
Product Reviews in Hawaii
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Product Reviews · Hawaii
Best Weed Killer for Lawns: Match It to the Weed in Hawaii
There is no best weed killer for lawns, only the right one for your weed: the seven chemistries that matter, what each kills, and the one that kills grass too.
Product Reviews · Hawaii
Organic Weed Killer for Lawns: The One That Works in Hawaii
The organic weed killer that works on lawns is iron — it burns broadleaf weeds and moss in hours without harming grass. What it won't do: kill the roots.
Hawaii Lawn Calendar
What your Bermuda lawn needs, season by season.
Spring
- There is no green-up to wait for; treat this as a period of the year rather than a starting gun
- Set mowing height by species and hold it: seashore paspalum below an inch, and the others to their own range
- Feed light and often rather than heavily — leaching soils and non-stop growth both argue for it
- Survey for little fire ant with bait sticks before doing any work that moves mulch or soil around
Summer
- Watch the leeward and windward halves of your own property differently; the rainfall gradient can operate across a single lot
- Scout for lawn armyworm and grass webworm damage, which appears as scattered thinning rather than a defined patch
- Do not assume a thin, unresponsive area is a fertility problem — nematodes are a real candidate here and the diagnostic centre will test for them
- Expect warm-humid disease pressure on zoysia and St. Augustine to continue rather than peak and pass
Fall
- Nothing changes seasonally, so use this period for the jobs a mainland calendar would put in autumn: aeration, dethatching, renovation
- Take a soil test — ADSC drop-off is Mondays 9 to 3:30 and Tuesdays 9 to 11, so plan the trip
- Read the phosphorus figure as availability, not total: these soils fix it
- Adjust irrigation as the trades shift rather than as temperatures fall
Winter
- Growth slows but does not stop, and neither does mowing
- Windward rain increases, so pull back irrigation and watch for disease rather than drought
- Leeward lawns still need water through this period; there is no dormancy to hide behind
- Plan any soil amendment now, because the leached Oxisols need feeding little and often all year rather than corrected once
Official Hawaii resources
Three things every guide here eventually sends you to do — and all three answers are specific to Hawaii rather than national: test your soil, read your own land-grant programme, and check whether the state has added anything to a product's federal label.
Soil testing
The land-grant lab that tests soil for residents here:
Agricultural Diagnostic Service Center (ADSC), University of Hawaii at Manoa CTAHROne centre covers soil nutrients and pH, plant tissue analysis, insect identification and plant disease diagnosis including NEMATODES — which matters here, because a thin Hawaii lawn that will not respond to fertilizer is a plausible nematode problem and there is nowhere else local to confirm it. Sample drop-off is narrow: Mondays 9 a.m. to 3:30 p.m. and Tuesdays 9 to 11 a.m., with payment online beforehand.
Why the number matters more than the bag: soil pH in Hawaii.
Turfgrass research
Every guide here defers to your own land-grant programme somewhere. This is it:
CTAHR Extension and the UH Master Gardener programmeUniversity of Hawaii at Manoa, College of Tropical Agriculture and Human Resources
CTAHR's turf publications are the only body of work written for these species in this climate — its guidance on destructive turf caterpillars and on little fire ant has no mainland equivalent, and the state's lawn armyworm is a species that does not occur elsewhere in the country.
Where their advice and a national rule of thumb disagree, follow theirs — they trialled it in 9a–13a.
Pesticide regulation
Pesticide authority sits with the state department of agriculture:
Hawaii Department of AgriculturePesticides Branch, Plant Industry Division
Hawaii has legislated ahead of the federal position before — Act 45 of 2018 banned chlorpyrifos while it was still federally registered — so checking the state list rather than assuming a nationally sold product is usable here is a real step, not a formality.
Restrictions we found printed on labels: Hawaii product restrictions.
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