Maui County, HI — Planting Guide
June in Maui County, Hawaii — your action list
A quick June briefing for Maui County, Hawaii gardeners — what's urgent, what's next, and what can wait.
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Survive, don't thrive
June-August is endurance gardening. Keep okra, peppers, sweet potatoes, and southern peas alive. Harvest everything daily before the heat damages produce on the vine.
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Start fall tomato seeds indoors
Yes, indoors — under lights or in AC. They'll be ready to transplant in August when temperatures briefly moderate.
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Add compost to empty beds
Empty beds get a thick layer of compost + mulch to suppress weeds and feed the soil for fall planting.
Maui County is in USDA Zone 12b. The average last spring frost is January 1 and the first fall frost is December 31, giving you a growing season of approximately 200 days.
At an elevation of 24 ft, Maui County receives approximately 75.9 in of rainfall annually. Summer highs average 91°F with winter lows around 71°F. The predominant soil type is Silty Clay.
🌡️ Zone
12b (55°F to 60°F min)
❄️ Last Frost
January 1
🍂 First Frost
December 31
📅 Growing Season
200 days
⛰️ Elevation
24 ft
🌧️ Annual Rainfall
75.9 in
Monthly Watering Calendar for Maui County
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
Quick context: The 1-inch-per-week rule applies to most vegetable crops. Maui County averages 76" a year — divide by 52 and compare to that 1" target. Some months are above, some below; that's where the calendar earns its keep.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 9.7 in | 12 days | — | Low |
| Feb | 8.8 in | 9 days | — | Low |
| Mar | 11.3 in | 10 days | — | Low |
| Apr | 6.9 in | 8 days | — | Low |
| May | 3.8 in | 9 days | 0.5 in | Low |
| Jun | 2.4 in | 5 days | 1.9 in | High |
| Jul | 1.8 in | 5 days | 2.5 in | High |
| Aug | 2.6 in | 5 days | 1.7 in | High |
| Sep | 3.3 in | 6 days | 1 in | Moderate |
| Oct | 6.7 in | 8 days | — | Low |
| Nov | 9 in | 11 days | — | Low |
| Dec | 9.6 in | 11 days | — | Low |
Annual total: 75.9 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.
Maui County Soil Profile
Soil Type
Silty Clay
Soil pH
5.4-6.5
Drainage
Well Drained
Gardening Difficulty Score
Maui County offers good growing conditions. A little planning around frost dates goes a long way.
No frost countdown needed. Frost is exceptional in this area — most years record zero frost days. Plan around heat and rainfall instead.
Local Gardening Help in Maui County
Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Maui County's climate and soil.
County Extension Office
Maui County University of Hawaii CTAHR Extension Extension Office
Phone: 808-956-8397
Visit Extension Office Website →
Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.
Master Gardener Program
Free gardening help from trained volunteers
Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.
Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.
Soil Testing
Available through your extension office
Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.
Services Available in Maui County
Finding local nurseries & garden centers in Maui County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Maui County's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.
How to Find Them
Search for "nurseries near Maui County HI" or "garden center Maui County" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.
Community gardens & gardening groups
Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Maui County HI" or check your extension office and local parks department. Facebook groups like "Maui County Gardeners" or "Hawaii Gardening" are also excellent for local advice and plant swaps.
What to Plant Next in Maui County
In a year-round growing climate, succession planning isn't about beating frost — it's about matching the next crop to the next season's heat.
Cool-season crops typically finish March–April as temperatures climb. Don't replant lettuce or brassicas now — they'll bolt within weeks. Switch to heat-lovers.
Spring tomato vines fade as summer humidity rises. Pull them by June and plant heat-survivors that thrive in the conditions tomatoes hate.
As humidity drops in September–October, the second growing season opens. Plant transplants of tomatoes, peppers, eggplant — they'll set fruit through fall and into winter.
Winter is your "spring" — direct-sow every 2 weeks for continuous lettuce, spinach, and radish harvests. Plant strawberries, garlic, and onions. Brassicas planted now finish in January–March.
Sunlight & Day Length in Maui County
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
What this means for you: Day length triggers flowering in many crops. Some need short days (sweet potatoes), some long (most flowers), and some are day-neutral (most modern tomatoes). Maui County's latitude determines which varieties fit your beds.
Longest Day
13.3 hours
Summer solstice daylight
Shortest Day
10.7 hours
Winter solstice daylight
Peak Sun Hours
9.2 hr/day peak (summer)
Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.
Onion tip: Your shorter days favor short-day onion varieties like Vidalia, Texas 1015, and Red Creole. Plant in fall for best results.
View detailed monthly data
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 10.9 hr | 5.9 hr | Short day |
| February | 11.3 hr | 6.6 hr | Short day |
| March | 11.9 hr | 6.7 hr | Short day |
| April | 12.5 hr | 6.4 hr | Neutral |
| May | 13 hr | 7.8 hr | Neutral |
| June | 13.3 hr | 8.3 hr | Neutral |
| July | 13.2 hr | 9.2 hr | Neutral |
| August | 12.7 hr | 8.3 hr | Neutral |
| September | 12.1 hr | 7.2 hr | Neutral |
| October | 11.5 hr | 6.6 hr | Short day |
| November | 11 hr | 5.8 hr | Short day |
| December | 10.7 hr | 5.8 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting in Maui County
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Quick context: Soil temperature is a leading indicator. A black plastic mulch can warm soil 5-10°F faster than bare ground — meaningful in Maui County's spring if you're trying to plant tomatoes earlier.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from Jan through Dec.
Best Month to Compost
Feb
Microbial activity peaks when soil is warm.
Active Composting
12 months
Nearly year-round composting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 65°F | 70°F | ♻️ Active | ~14 weeks |
| Feb | 67°F | 69°F | 🔥 Peak | ~8 weeks |
| Mar | 72°F | 71°F | 🔥 Peak | ~8 weeks |
| Apr | 77°F | 75°F | 🔥 Peak | ~8 weeks |
| May | 81°F | 83°F | 🔥 Peak | ~8 weeks |
| Jun | 91°F | 89°F | 🔥 Peak | ~8 weeks |
| Jul | 95°F | 92°F | 🔥 Peak | ~8 weeks |
| Aug | 98°F | 94°F | 🔥 Peak | ~8 weeks |
| Sep | 93°F | 92°F | 🔥 Peak | ~8 weeks |
| Oct | 85°F | 88°F | 🔥 Peak | ~8 weeks |
| Nov | 77°F | 81°F | 🔥 Peak | ~8 weeks |
| Dec | 67°F | 74°F | 🔥 Peak | ~8 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Maui County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
What this means for you: Two gardeners can grow identical seeds and get wildly different results based on pest pressure alone. Maui County's climate sets a floor on what's possible without intervention.
Insect Pest Pressure
High — expect multiple pest generations. Preventative measures essential.
Disease Risk
High fungal/bacterial risk. Space plants for airflow, water at soil level.
Seasonal Risk
View 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | High | Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec |
| Whiteflies | High | Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec |
| Spider mites | High | Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov |
| Thrips | Moderate | Mar, Apr, May, Jun, Jul, Aug, Sep |
| Scale insects | Moderate | Apr, May, Jun, Jul, Aug, Sep, Oct |
| Nematodes | Low | May, Jun, Jul, Aug, Sep |
Organic pest management tips
- Install physical barriers: floating row covers, copper tape for slugs, mesh netting
- Apply Bt (Bacillus thuringiensis) for caterpillar control — safe for beneficial insects
- Use kaolin clay spray to deter a wide range of insects on fruiting crops
- Release beneficial insects: ladybugs for aphids, parasitic wasps for caterpillars
- Apply neem oil weekly during high-pressure months
- Mulch heavily (3-4 inches) to reduce soil-borne disease splash
Cover Crops for Maui County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.
For new gardeners: Bare soil is wasted soil — it loses nutrients to rain, dries out, compacts, and gets taken over by weeds. Cover crops (clovers, ryegrass, vetch, peas) are the "between seasons" trick that makes soil better every year. In Maui County, you can fit a cover crop into the gaps.
Spring Cover Crops (1 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Cowpeas (southern peas) | Jan 6 | Oct 22 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
Wind & Microclimate in Maui County
Why it matters: Wind affects three things gardeners forget: how fast soil dries (more wind = more watering), whether pollinators can work (calm beats gusty), and whether your trellised crops stay upright. Maui County sees 14.1 mph on average — a forgiving baseline.
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 13 mph Summer: 14 mph
Fall: 13 mph Winter: 12 mph
Prevailing wind: NE. Windy area — plant a windbreak hedge on the NE side of your garden.
Windbreak Benefit
7.4/10
Strongly recommended — a windbreak (fence, hedge, or row of tall crops like corn or sunflowers) will significantly improve garden yields.
Frost Pocket Risk
Moderate
Some terrain variation (573 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.
Rainwater Harvesting in Maui County
How much water you can collect, when to collect it, and what size system you need for your garden.
The practical takeaway: Building a rainwater system is mostly about doing the math: roof area × annual rainfall × 0.6 = gallons you could realistically capture. For Maui County, that's your 76" times your roof.
Annual Collection
37,828 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
6 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 1,250 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
Jan, Mar, Nov, Dec
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Jun, Jul, Aug
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 75.9 inches of rain per year
- A 1,000 sq ft roof can collect roughly 37,828 gallons annually
- Rainwater harvesting is fully legal in your state
- Your area gets ample rainfall — even small barrels make a big difference
- Consider a rain garden to handle overflow during heavy rainfall months
Soil & Growing Conditions in Maui County
Soil Type
Silty Clay
Soil pH 5.4–6.5 · Well Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 1.5/10
Maui County has very low drought pressure. Natural rainfall usually meets garden needs — water only during extended dry spells.
Season Tips
200-day frost-free season
Plenty of time for warm-season crops. Start heat-lovers indoors 6–8 weeks before last frost to maximise your harvest window.
Your Free Printable Garden Planner
Plan every bed, every planting, every harvest — in one place. This 22-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.
Recommended for Your Garden
Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.
Cedar raised bed kit — ideal for poor soil, clay, or small-space gardening.
Improve drainage and aeration in heavy clay soils with horticultural perlite.
🥬 Vegetables to Grow in Maui County
4 vegetables that grow well in Zone 12b with planting dates for Maui County.
Show all 4 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Ginger | Nov 20 | Jan 1 | Jan 8 | — | Sep 10 – Nov 19 | 240–300 |
| Microgreens | Dec 4 | Dec 11 | Jan 1 | Nov 5 | Jan 8 – Feb 5 | 7–21 |
| Turmeric | Nov 20 | Jan 1 | Jan 8 | — | Sep 10 – Nov 19 | 240–300 |
| Yam | Nov 20 | Jan 1 | Jan 8 | — | Jul 9 – Dec 24 | 180–330 |
Monthly Planting Guide for Maui County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Maui County.
Frequently Asked Questions
What planting zone is Maui County, HI?
Maui County is in USDA Hardiness Zone 12b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.
When is the last frost in Maui County, HI?
Based on 1 years of NOAA weather station data, the median last spring frost in Maui County falls around January 1. Use April 15 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Maui County, HI?
The median first fall frost in Maui County arrives around December 31. In cold years it can arrive as early as April 15; in mild years as late as April 15. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Maui County?
Maui County has a frost-free growing season of approximately 200 days. This long season supports multiple succession plantings and warm-season crops that need extended heat, like sweet potatoes and melons.
What is the soil like in Maui County for gardening?
Maui County has predominantly Silty Clay soil with a pH range of 5.4–6.5 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Maui County?
Maui County has commercial agriculture that includes Cattle, Macadamia Nuts, Coffee, Tropical Fruits. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Maui County a good location for home gardening?
Maui County scores 76/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. This is an above-average location for home gardening with relatively predictable growing conditions.
Your Maui County Garden Planner — Free
A 22-page printable planner built for Maui County (Zone 12b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Seed Saving & Storage Guide
Most saved seeds go bad before next season. This shows exactly when to pick, how to dry, and where to store seeds from 200 plants so yours don't.
- 200 plants, step-by-step: life cycle, pollination type, isolation
- Exact temperature + humidity ranges that keep seeds viable
- Bonus: searchable Google Sheets tracker + custom GPT assistant
Composting Guide for Homesteaders
Turn kitchen scraps and yard waste into compost that actually feeds the garden — instead of a pile that smells, attracts pests, and never breaks down.
- 14 sections on composting methods, soil science, and troubleshooting
- The 7-step hot-compost system from start to finish
- Bonus tools: troubleshooting chart, safety guide, monitoring log