Humboldt County, CA — Planting Guide
Humboldt County is in USDA Zone 9a. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 275 days.
At an elevation of 148 ft, Humboldt County receives approximately 22.1 in of rainfall annually. Summer highs average 87°F with winter lows around 57°F. The predominant soil type is Sandy Loam.
Based on 27 years of NOAA climate station data, the last frost date here varies by 81 days year to year — ranging from January 12 in warm years to April 2 in cold years. Humboldt County scores 68/100 (Good) on the Microclimate Index.
🌡️ Zone
9a (20°F to 25°F min)
❄️ Last Frost
February 27
🍂 First Frost
November 28
📅 Growing Season
275 days
⛰️ Elevation
148 ft
🌧️ Annual Rainfall
22.1 in
Monthly Watering Calendar
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 4.8 in | 8 days | — | None |
| Feb | 5 in | 9 days | — | Low |
| Mar | 3.3 in | 8 days | 1 in | Moderate |
| Apr | 1.7 in | 4 days | 2.6 in | High |
| May | 0.5 in | 1 days | 3.8 in | Critical |
| Jun | 0.1 in | 1 days | 4.2 in | Critical |
| Jul | 0 in | 0 days | 4.3 in | Critical |
| Aug | 0 in | 0 days | 4.3 in | Critical |
| Sep | 0.3 in | 0 days | 4 in | Critical |
| Oct | 0.8 in | 3 days | 3.5 in | Critical |
| Nov | 1.9 in | 5 days | 2.4 in | High |
| Dec | 3.7 in | 9 days | — | None |
Annual total: 22.1 in. Gardens typically need ~1 inch of water per week during the growing season. Months marked "None" for extra water are outside the active growing season for your zone — most gardens are dormant and don't need irrigation during those months.
Humboldt County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.2-6.8
Drainage
Well Drained
Frost Risk Probability
Based on 27 years of NOAA weather station data from 3 stations
Beginners: Plant frost-sensitive crops (tomatoes, peppers, squash) after the "Safe" date on the left. Harvest or cover them before the "Protect by" date on the right. Hardy crops (lettuce, peas, kale) can go in the yellow transition zones.
How to read this table: "Conservative" means you're safe from frost 9 out of 10 years — best for beginners and frost-sensitive crops. "Average year" is the typical date. "Aggressive" means only 1 in 10 years is that warm — experienced gardeners with frost protection can try these dates.
| Planting Strategy | Last Spring Frost | First Fall Frost | Frost-Free Days |
|---|---|---|---|
| Conservative (safest) | Apr 2 | Dec 18 | 260 days |
| Cautious | Mar 15 | Dec 7 | 267 days |
| Average year | Feb 27 | Nov 28 | 274 days |
| Optimistic | Feb 13 | Nov 23 | 283 days |
| Aggressive (risky) | Jan 12 | Nov 10 | 302 days |
Not very — frost dates can vary by ±81 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Slightly — seasons are trending a bit longer (0.4 days/decade). Historical frost dates are still reliable for planning.
Gardening Difficulty Score
Humboldt County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Humboldt 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 Humboldt County's climate and soil.
County Extension Office
Humboldt County University of California Cooperative Extension Extension Office
Phone: 530-750-1200
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 Humboldt County
Finding local nurseries & garden centers in Humboldt County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Humboldt 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 Humboldt County CA" or "garden center Humboldt 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 Humboldt County CA" or check your extension office and local parks department. Facebook groups like "Humboldt County Gardeners" or "California Gardening" are also excellent for local advice and plant swaps.
What to Plant After Your Harvest
After your first crops finish, use the remaining frost-free days to grow a second round.
Show 6 more succession options
Sunlight & Day Length
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
14.9 hours
Summer solstice daylight
Shortest Day
9.1 hours
Winter solstice daylight
Peak Sun Hours
13.6 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 long summer days (14+ hours) support long-day onion varieties like Walla Walla, Sweet Spanish, and Ailsa Craig.
View detailed monthly data
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 9.4 hr | 5.6 hr | Short day |
| February | 10.4 hr | 6 hr | Short day |
| March | 11.7 hr | 7.8 hr | Short day |
| April | 13.1 hr | 9.2 hr | Neutral |
| May | 14.3 hr | 11.2 hr | Long day |
| June | 14.9 hr | 13.6 hr | Long day |
| July | 14.6 hr | 13.5 hr | Long day |
| August | 13.6 hr | 12 hr | Neutral |
| September | 12.3 hr | 10.1 hr | Neutral |
| October | 10.9 hr | 8.1 hr | Short day |
| November | 9.7 hr | 5.7 hr | Short day |
| December | 9.1 hr | 5.1 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting Calendar
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from Apr through Nov.
Best Month to Compost
Apr
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 | 51°F | 56°F | ♻️ Active | ~14 weeks |
| Feb | 53°F | 56°F | ♻️ Active | ~14 weeks |
| Mar | 57°F | 62°F | ♻️ Active | ~14 weeks |
| Apr | 66°F | 66°F | 🔥 Peak | ~8 weeks |
| May | 74°F | 73°F | 🔥 Peak | ~8 weeks |
| Jun | 84°F | 82°F | 🔥 Peak | ~8 weeks |
| Jul | 92°F | 88°F | 🔥 Peak | ~8 weeks |
| Aug | 93°F | 89°F | 🔥 Peak | ~8 weeks |
| Sep | 90°F | 86°F | 🔥 Peak | ~8 weeks |
| Oct | 76°F | 81°F | 🔥 Peak | ~8 weeks |
| Nov | 65°F | 71°F | 🔥 Peak | ~8 weeks |
| Dec | 56°F | 63°F | ♻️ Active | ~14 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Humboldt County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
High — expect multiple pest generations. Preventative measures essential.
Disease Risk
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | High | Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov |
| Whiteflies | High | Apr, May, Jun, Jul, Aug, Sep, Oct, Nov |
| Spider mites | High | May, Jun, Jul, Aug, Sep, Oct |
| Fire ants | High | Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov |
| Thrips | Moderate | Apr, May, Jun, Jul, Aug |
| Leaf miners | Low | Mar, Apr, May, Jun |
Organic pest management tips
- Use row covers on susceptible crops during peak pest months
- Apply neem oil preventatively every 7-14 days during active pest season
- Interplant with strong-scented herbs (basil, marigold) to confuse pests
- Hand-pick larger pests (beetles, caterpillars) in early morning when they're sluggish
- Practice crop rotation — never plant the same family in the same spot within 3 years
Cover Crops for Humboldt County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Fall Cover Crops (4 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Austrian winter peas | Sep 29 | Feb 6 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Oct 6 | Feb 13 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Oct 6 | Feb 13 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Sep 6 | Feb 13 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
Spring Cover Crops (4 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Mar 3 | Oct 3 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Cowpeas (southern peas) | Mar 5 | Oct 3 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
| Sorghum-sudan grass | Mar 8 | Sep 19 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Jan 30 | Sep 26 | ✓ Yes | Living mulch, fixes nitrogen, permanent ground cover |
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Sunflowers | Mar 10 | Nov 14 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 13 mph Summer: 10 mph
Fall: 9 mph Winter: 9 mph
Prevailing wind: W. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
4.8/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (877 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
11,014 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
7 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 2,500 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
Jan, Feb, Mar, Dec
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
May, Jun, Jul, Aug, Sep, Oct
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 22.1 inches of rain per year
- A 1,000 sq ft roof can collect roughly 11,014 gallons annually
- Rainwater harvesting is fully legal in your state
- Stock up on stored water before your dry season (May, Jun, Jul)
- Use a first-flush diverter to keep roof debris out of your collection
Soil & Growing Conditions in Humboldt County
Soil Type
Sandy Loam
Soil pH 6.2–6.8 · Well Drained drainage
Good candidate for raised beds to maximise drainage and extend the season.
Watering Needs
Drought stress: 3.5/10
Low-to-moderate drought stress. Plan to water 1–2 times per week during peak summer. (22.1 in. annual rainfall)
Season Tips
275-day frost-free season
Your long season supports multiple successions and heat-demanding crops like melons, sweet potatoes, and peppers. Plant warm-season crops as soon as soil warms.
Free Garden Planner
Plan your entire garden season — organize planting dates, track what you're growing, and know exactly when to start seeds, transplant, and harvest.
Recommended for Your Garden
Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.
Retain moisture and nutrients in sandy soils with expanded vermiculite.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
🥬 Vegetables to Grow in Humboldt County
115 vegetables that grow well in Zone 9a with planting dates for Humboldt County.
Show all 115 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Jan 30 | Feb 27 | Mar 6 | May 29 – Jul 3 | 80–100 |
| Amaranth | Jan 16 | Feb 27 | Mar 6 | Jun 5 – Jul 24 | 90–120 |
| Artichoke | — | — | Mar 13 | Jul 17 – Sep 25 | 120–180 |
| Arugula | Jan 30 | Feb 6 | Feb 27 | Apr 3 – Jun 5 | 30–50 |
| Asparagus | — | — | Mar 13 | — | 730–1095 |
| Beets | — | Feb 6 | — | Apr 3 – May 1 | 50–70 |
| Belgian Endive | Jan 30 | Feb 6 | Feb 27 | Jun 19 – Aug 14 | 110–150 |
| Bitter Melon | Jan 16 | Feb 27 | Mar 6 | May 8 – Jun 19 | 60–90 |
| Black Beans | — | Mar 6 | — | Jun 5 – Jul 24 | 90–120 |
| Bok Choy | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 15 | 40–60 |
| Broccoli | Jan 30 | Feb 6 | Feb 27 | May 1 – Jun 12 | 60–90 |
| Broccoli Rabe | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 15 | 40–60 |
| Brussels Sprouts | Jan 30 | Feb 6 | Feb 27 | May 29 – Jul 24 | 90–130 |
| Butternut Squash | Jan 30 | Feb 27 | Mar 6 | Jun 5 – Jul 10 | 85–110 |
| Cabbage | Jan 30 | Feb 6 | Feb 27 | May 1 – Jun 26 | 60–100 |
| Calabash | Jan 16 | Feb 27 | Mar 6 | May 29 – Jul 24 | 80–120 |
| Cardoon | — | — | Mar 13 | Jul 17 – Aug 28 | 120–150 |
| Carrots | — | Feb 6 | — | Apr 10 – May 15 | 60–80 |
| Cauliflower | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 26 | 55–100 |
| Celeriac | Jan 30 | Feb 6 | Feb 27 | Jun 12 – Jul 17 | 100–120 |
| Celery | Jan 30 | Feb 6 | Feb 27 | May 22 – Jul 17 | 80–120 |
| Celtuce | Jan 30 | Feb 6 | Feb 27 | May 1 – Jun 12 | 60–90 |
| Chard | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 12 | 50–60 |
| Chayote | Jan 16 | Feb 27 | Mar 6 | Jul 10 – Sep 18 | 120–180 |
| Chickpeas | Jan 30 | Feb 6 | Feb 27 | May 22 – Jul 3 | 80–110 |
| Chicory | Jan 30 | Feb 6 | Feb 27 | May 1 – Jun 12 | 60–85 |
| Chinese Cabbage | Jan 30 | Feb 6 | Feb 27 | Apr 24 – May 22 | 50–70 |
| Christmas Lima Beans | Jan 16 | Feb 27 | Mar 6 | May 29 – Jul 3 | 80–100 |
| Collard Greens | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 26 | 55–75 |
| Corn | — | Mar 6 | — | May 8 – Jul 3 | 60–100 |
| Cowpeas | — | Mar 6 | — | May 8 – Jun 19 | 60–90 |
| Cress | Jan 30 | Feb 6 | Feb 27 | Mar 13 – Apr 3 | 14–21 |
| Crookneck Squash | Jan 30 | Feb 27 | Mar 6 | Apr 24 – May 22 | 45–60 |
| Crosne | — | Feb 6 | — | Jul 10 – Sep 11 | 150–200 |
| Cucumber | Jan 30 | Feb 27 | Mar 6 | May 1 – Jun 26 | 50–70 |
| Daikon | — | Feb 6 | — | Apr 3 – May 1 | 50–70 |
| Delicata Squash | Jan 30 | Feb 27 | Mar 6 | May 29 – Jul 3 | 80–100 |
| Edamame | — | Mar 6 | — | May 22 – Jul 3 | 75–100 |
| Eggplant | Jan 16 | Feb 27 | Mar 6 | May 15 – Jul 17 | 65–85 |
| Endive | Jan 30 | Feb 6 | Feb 27 | Apr 17 – May 22 | 45–65 |
| Escarole | Jan 30 | Feb 6 | Feb 27 | Apr 24 – May 22 | 50–70 |
| Fava Beans | Jan 30 | Feb 6 | Feb 27 | May 15 – Jun 26 | 75–100 |
| Fennel | Jan 16 | Feb 27 | Mar 6 | May 8 – Jun 19 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Ginger | Jan 16 | Feb 27 | Mar 6 | Nov 6 – Jan 1 | 240–300 |
| Green Beans | — | Mar 6 | — | May 1 – Jun 26 | 50–65 |
| Horseradish | — | — | Mar 13 | Jul 17 – Sep 25 | 120–180 |
| Hot Peppers | Jan 16 | Feb 27 | Mar 6 | May 15 – Aug 21 | 70–120 |
| Hubbard Squash | Jan 30 | Feb 27 | Mar 6 | Jun 19 – Jul 24 | 100–120 |
| Jicama | Jan 16 | Feb 27 | Mar 6 | Jul 10 – Sep 18 | 120–180 |
| Kabocha | Jan 30 | Feb 27 | Mar 6 | Jun 5 – Jul 3 | 85–100 |
| Kai Lan | Jan 30 | Feb 6 | Feb 27 | Apr 17 – May 15 | 45–60 |
| Kale | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 19 | 50–70 |
| Kidney Beans | — | Mar 6 | — | Jun 5 – Jul 10 | 85–110 |
| Kohlrabi | Jan 30 | Feb 6 | Feb 27 | Apr 17 – May 22 | 45–65 |
| Komatsuna | Jan 30 | Feb 6 | Feb 27 | Apr 3 – May 8 | 35–50 |
| Leeks | Jan 30 | Feb 6 | Feb 27 | May 29 – Aug 14 | 90–150 |
| Lentils | Jan 30 | Feb 6 | Feb 27 | May 22 – Jul 3 | 80–110 |
| Lettuce | Jan 30 | Feb 6 | Feb 27 | Apr 3 – Jun 12 | 30–60 |
| Lima Beans | — | Mar 6 | — | May 8 – Jun 19 | 60–90 |
| Loofah | Jan 16 | Feb 27 | Mar 6 | Jun 19 – Aug 21 | 100–150 |
| Luffa | Jan 16 | Feb 27 | Mar 6 | Jun 5 – Aug 21 | 90–150 |
| Mache | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 15 | 40–60 |
| Malabar Spinach | Jan 16 | Feb 27 | Mar 6 | May 1 – May 29 | 55–70 |
| Melon | Jan 30 | Feb 27 | Mar 6 | May 15 – Jul 3 | 70–100 |
| Microgreens | Jan 30 | Feb 6 | Feb 27 | Mar 6 – Apr 3 | 7–21 |
| Mitsuba | Jan 30 | Feb 6 | Feb 20 | Apr 17 – Jun 12 | 50–70 |
| Mizuna | Jan 30 | Feb 6 | Feb 27 | Apr 3 – May 1 | 30–45 |
| Mustard Greens | Jan 30 | Feb 6 | Feb 27 | Apr 3 – Jun 5 | 30–50 |
| Napa Cabbage | Jan 30 | Feb 6 | Feb 27 | Apr 24 – May 29 | 55–75 |
| New Zealand Spinach | Jan 16 | Feb 27 | Mar 6 | May 1 – May 29 | 55–70 |
| Okra | Jan 16 | Feb 27 | Mar 6 | May 1 – Jun 26 | 50–65 |
| Onion | Jan 30 | Feb 6 | Feb 27 | May 29 – Jul 17 | 90–120 |
| Pac Choi | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 8 | 40–55 |
| Parsnip | — | Feb 6 | — | May 22 – Jul 3 | 100–130 |
| Patty Pan Squash | Jan 30 | Feb 27 | Mar 6 | Apr 24 – May 22 | 45–60 |
| Peas | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 19 | 55–70 |
| Peppers | Jan 16 | Feb 27 | Mar 6 | May 8 – Jul 17 | 60–90 |
| Pole Beans | Jan 16 | Feb 27 | Mar 6 | May 1 – Jun 26 | 55–70 |
| Potatoes | Jan 16 | Feb 27 | Mar 6 | May 15 – Jul 24 | 70–120 |
| Pumpkin | Jan 30 | Feb 27 | Mar 6 | Jun 5 – Jul 24 | 85–120 |
| Purslane | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 15 | 40–60 |
| Radicchio | Jan 30 | Feb 6 | Feb 27 | May 1 – Jun 5 | 60–80 |
| Radish | — | Feb 6 | — | Mar 6 – Mar 27 | 22–35 |
| Romanesco | Jan 30 | Feb 6 | Feb 27 | May 15 – Jun 26 | 75–100 |
| Rutabaga | — | Feb 6 | — | May 1 – Jun 5 | 80–100 |
| Salsify | — | Feb 6 | — | May 22 – Jul 3 | 100–130 |
| Savoy Cabbage | Jan 30 | Feb 6 | Feb 27 | May 8 – Jul 3 | 70–110 |
| Scallions | Jan 30 | Feb 6 | Feb 27 | Apr 24 – May 22 | 50–70 |
| Scarlet Runner Beans | Jan 16 | Feb 27 | Mar 6 | May 8 – Jun 12 | 60–80 |
| Shallot | Jan 30 | Feb 6 | Feb 27 | May 29 – Jul 17 | 90–120 |
| Shiso | Jan 16 | Mar 6 | Mar 6 | May 1 – Jun 26 | 50–70 |
| Snap Peas | Jan 16 | Feb 27 | Mar 6 | May 1 – Jun 26 | 55–70 |
| Snow Peas | Jan 30 | Feb 6 | Feb 27 | Apr 24 – Jun 19 | 50–65 |
| Soybeans | — | Mar 6 | — | May 29 – Jul 24 | 80–120 |
| Spaghetti Squash | Jan 30 | Feb 27 | Mar 6 | Jun 5 – Jul 3 | 85–100 |
| Spinach | Jan 30 | Feb 6 | Feb 27 | Apr 3 – Jun 5 | 35–50 |
| Squash (Summer) | Jan 30 | Feb 27 | Mar 6 | Apr 24 – Jun 26 | 45–65 |
| Squash (Winter) | Jan 30 | Feb 27 | Mar 6 | May 29 – Jul 24 | 80–120 |
| Sunchoke | — | — | Mar 13 | Jul 3 – Aug 28 | 110–150 |
| Sunflower | Jan 16 | Feb 27 | Mar 6 | May 15 – Jul 3 | 70–100 |
| Sweet Corn | — | Mar 6 | — | May 8 – Jun 19 | 60–90 |
| Sweet Potatoes | Jan 16 | Feb 27 | Mar 6 | Jun 5 – Jul 24 | 90–120 |
| Tatsoi | Jan 30 | Feb 6 | Feb 27 | Apr 3 – May 8 | 35–50 |
| Tomatillo | Jan 16 | Feb 27 | Mar 6 | May 8 – Jul 17 | 60–85 |
| Tomatoes | Jan 16 | Feb 27 | Mar 6 | May 8 – Jul 17 | 60–85 |
| Turmeric | Jan 16 | Feb 27 | Mar 6 | Nov 6 – Jan 1 | 240–300 |
| Turnip | — | Feb 6 | — | Mar 20 – Apr 24 | 40–60 |
| Watercress | Jan 30 | Feb 6 | Feb 27 | Apr 10 – May 15 | 40–60 |
| Watermelon | Jan 30 | Feb 27 | Mar 6 | May 15 – Jul 3 | 70–100 |
| Wax Beans | — | Mar 6 | — | May 1 – Jun 26 | 50–65 |
| Winter Melon | Jan 16 | Feb 27 | Mar 6 | Jun 5 – Jul 24 | 90–120 |
| Yam | Jan 16 | Feb 27 | Mar 6 | Sep 4 – Jan 1 | 180–330 |
| Yard Long Beans | Jan 16 | Feb 27 | Mar 6 | May 1 – Jun 12 | 55–80 |
| Zucchini | Jan 30 | Feb 27 | Mar 6 | Apr 24 – Jun 19 | 45–60 |
🍓 Fruits to Grow in Humboldt County
24 fruits that grow well in Zone 9a with planting dates for Humboldt County.
Show all 24 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Mar 13 | Jun 12 – Sep 25 | 90–180 |
| Blackberries | — | — | Mar 13 | — | 365–730 |
| Boysenberries | — | — | Mar 13 | — | 365–730 |
| Cantaloupe | — | — | Mar 13 | May 22 – Jun 26 | 70–90 |
| Che Fruit | — | — | Mar 13 | — | 1095–1825 |
| Dragon Fruit | — | — | Mar 13 | — | 365–730 |
| Elderberries | — | — | Mar 13 | — | 730–1095 |
| Figs | — | — | Mar 13 | — | 730–1825 |
| Goji Berries | — | — | Mar 13 | — | 730–1095 |
| Grapes | — | — | Mar 13 | — | 730–1095 |
| Ground Cherry | — | — | Mar 13 | May 22 – Jul 17 | 65–80 |
| Guava | — | — | Mar 13 | — | 365–730 |
| Honeydew | — | — | Mar 13 | Jun 5 – Jul 17 | 80–110 |
| Kiwi | — | — | Mar 13 | — | 1095–1825 |
| Loquat | — | — | Mar 13 | — | 730–1825 |
| Mulberries | — | — | Mar 13 | — | 730–1825 |
| Passion Fruit | — | — | Mar 13 | — | 365–545 |
| Pawpaw | — | — | Mar 13 | — | 1095–2555 |
| Persimmon | — | — | Mar 13 | — | 1095–2555 |
| Pomegranate | — | — | Mar 13 | — | 730–1095 |
| Quince | — | — | Mar 13 | — | 1095–1825 |
| Raspberries | — | — | Mar 13 | — | 365–730 |
| Serviceberries | — | — | Mar 13 | — | 730–1095 |
| Strawberries | — | — | Mar 13 | Jun 12 – Jan 8 | 90–365 |
🌿 Herbs to Grow in Humboldt County
40 herbs that grow well in Zone 9a with planting dates for Humboldt County.
Show all 40 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Anise | Jan 30 | Feb 6 | Feb 20 | May 22 – Aug 7 | 90–120 |
| Basil | Jan 16 | Mar 6 | Mar 6 | May 1 – Jul 3 | 50–75 |
| Bee Balm | — | — | Mar 6 | Jun 5 – Aug 21 | 90–120 |
| Borage | Jan 30 | Feb 6 | Feb 20 | Apr 17 – Jun 5 | 50–60 |
| Caraway | Jan 30 | Feb 6 | Feb 20 | — | 365–450 |
| Catnip | — | — | Mar 6 | May 8 – Jul 10 | 60–80 |
| Chamomile | Jan 30 | Feb 6 | Feb 20 | Apr 24 – Jul 3 | 60–90 |
| Chervil | Jan 30 | Feb 6 | Feb 20 | Apr 3 – Jun 5 | 40–60 |
| Chives | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Cilantro | Jan 30 | Feb 6 | Feb 20 | Apr 3 – Jun 5 | 40–60 |
| Comfrey | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Cumin | Jan 30 | Feb 6 | Feb 20 | Jun 5 – Aug 7 | 100–120 |
| Dill | Jan 30 | Feb 6 | Feb 20 | Apr 3 – Jun 5 | 40–60 |
| Echinacea | — | — | Mar 6 | Jul 10 – Oct 16 | 120–180 |
| Epazote | Jan 16 | Mar 6 | Mar 6 | Apr 24 – Jun 19 | 45–60 |
| Fennel (herb) | Jan 30 | Feb 6 | Feb 20 | Apr 24 – Jul 3 | 60–90 |
| Feverfew | — | — | Mar 6 | Jun 5 – Aug 21 | 90–120 |
| Garlic Chives | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Horehound | — | — | Mar 6 | May 22 – Jul 17 | 75–90 |
| Hyssop | — | — | Mar 6 | May 15 – Jul 17 | 70–90 |
| Lavender | — | — | Mar 6 | Jun 5 – Nov 6 | 90–200 |
| Lemon Balm | — | — | Mar 6 | May 8 – Jun 26 | 60–70 |
| Lemon Thyme | — | — | Mar 6 | May 15 – Jul 17 | 70–90 |
| Lemon Verbena | Jan 16 | Mar 6 | Mar 6 | May 8 – Jul 17 | 60–90 |
| Lemongrass | Jan 16 | Mar 6 | Mar 6 | May 22 – Aug 21 | 75–120 |
| Marjoram | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Mint | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Oregano | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Parsley | Jan 30 | Feb 6 | Feb 20 | Apr 24 – Jun 26 | 60–80 |
| Rosemary | — | — | Mar 6 | May 29 – Oct 16 | 80–180 |
| Rue | — | — | Mar 6 | May 15 – Jul 17 | 70–90 |
| Sage | — | — | Mar 6 | May 22 – Jul 17 | 75–90 |
| Savory | — | — | Mar 6 | May 1 – Jun 26 | 50–70 |
| Sorrel | Jan 30 | Feb 6 | Feb 20 | Apr 3 – Jun 5 | 40–60 |
| Stevia | Jan 16 | Mar 6 | Mar 6 | May 8 – Jul 17 | 60–90 |
| Tarragon | — | — | Mar 6 | May 8 – Jul 17 | 60–90 |
| Thai Basil | Jan 16 | Mar 6 | Mar 6 | May 1 – Jul 3 | 50–75 |
| Thyme | — | — | Mar 6 | May 15 – Jul 17 | 70–90 |
| Valerian | — | — | Mar 6 | Jul 10 – Oct 16 | 120–180 |
| Yarrow | — | — | Mar 6 | Jun 5 – Aug 21 | 90–120 |
Monthly Planting Guide for Humboldt County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Humboldt County.
Frequently Asked Questions
What planting zone is Humboldt County, CA?
Humboldt County is in USDA Hardiness Zone 9a. 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 Humboldt County, CA?
Based on 27 years of NOAA weather station data, the median last spring frost in Humboldt County falls around February 27. In 8 out of 10 years, last frost lands between January 12 and April 2 — a 81-day window of variability. Use April 2 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Humboldt County, CA?
The median first fall frost in Humboldt County arrives around November 28. In cold years it can arrive as early as November 10; in mild years as late as December 18. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Humboldt County?
Humboldt County has a frost-free growing season of approximately 275 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 Humboldt County for gardening?
Humboldt County has predominantly Sandy Loam soil with a pH range of 6.2–6.8 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Humboldt County?
Humboldt County has commercial agriculture that includes Grapes, Almonds, Hay. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Humboldt County a good location for home gardening?
Humboldt County scores 68/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Conditions here are moderate — most common crops grow well with standard timing and care.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Humboldt County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.
