Napa County, CA — Planting Guide
Napa County is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 274 days.
At an elevation of 449 ft, Napa County receives approximately 35 in of rainfall annually. Summer highs average 88°F with winter lows around 52°F. The predominant soil type is Loam.
Based on 30 years of NOAA climate station data, the last frost date here varies by 79 days year to year — ranging from January 13 in warm years to April 2 in cold years. Napa County scores 72/100 (Good) on the Microclimate Index.
🌡️ Zone
9a (20°F to 25°F min)
❄️ Last Frost
February 26
🍂 First Frost
November 26
📅 Growing Season
274 days
⛰️ Elevation
449 ft
🌧️ Annual Rainfall
35 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 | 7.5 in | 9 days | — | None |
| Feb | 7.8 in | 10 days | — | Low |
| Mar | 5.8 in | 8 days | — | Low |
| Apr | 2.3 in | 4 days | 2 in | High |
| May | 0.8 in | 1 days | 3.5 in | Critical |
| Jun | 0.2 in | 1 days | 4.1 in | Critical |
| Jul | 0 in | 0 days | 4.3 in | Critical |
| Aug | 0 in | 0 days | 4.3 in | Critical |
| Sep | 0.3 in | 1 days | 4 in | Critical |
| Oct | 1.3 in | 3 days | 3 in | High |
| Nov | 3.3 in | 6 days | 1 in | Moderate |
| Dec | 5.6 in | 9 days | — | None |
Annual total: 34.9 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.
Napa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.5
Drainage
Well Drained
Frost Risk Probability
Based on 30 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 17 | 259 days |
| Cautious | Mar 8 | Dec 4 | 271 days |
| Average year | Feb 26 | Nov 26 | 273 days |
| Optimistic | Feb 10 | Nov 22 | 285 days |
| Aggressive (risky) | Jan 13 | Nov 9 | 300 days |
Not very — frost dates can vary by ±79 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Gardening Difficulty Score
Napa County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Napa 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 Napa County's climate and soil.
County Extension Office
Napa 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 Napa County
Finding local nurseries & garden centers in Napa County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Napa 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 Napa County CA" or "garden center Napa 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 Napa County CA" or check your extension office and local parks department. Facebook groups like "Napa 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
14.7 hours
Summer solstice daylight
Shortest Day
9.3 hours
Winter solstice daylight
Peak Sun Hours
13.1 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 | 9.6 hr | 5.8 hr | Short day |
| February | 10.6 hr | 6.3 hr | Short day |
| March | 11.7 hr | 7.8 hr | Short day |
| April | 13 hr | 9.6 hr | Neutral |
| May | 14.1 hr | 11.6 hr | Long day |
| June | 14.7 hr | 13.1 hr | Long day |
| July | 14.4 hr | 12.6 hr | Long day |
| August | 13.5 hr | 11.6 hr | Neutral |
| September | 12.2 hr | 9.9 hr | Neutral |
| October | 11 hr | 7.9 hr | Short day |
| November | 9.9 hr | 6.2 hr | Short day |
| December | 9.3 hr | 5.2 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
May
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 | 52°F | 57°F | ♻️ Active | ~14 weeks |
| Feb | 53°F | 58°F | ♻️ Active | ~14 weeks |
| Mar | 60°F | 61°F | ♻️ Active | ~14 weeks |
| Apr | 65°F | 65°F | ♻️ Active | ~14 weeks |
| May | 74°F | 73°F | 🔥 Peak | ~8 weeks |
| Jun | 87°F | 83°F | 🔥 Peak | ~8 weeks |
| Jul | 95°F | 87°F | 🔥 Peak | ~8 weeks |
| Aug | 95°F | 92°F | 🔥 Peak | ~8 weeks |
| Sep | 88°F | 89°F | 🔥 Peak | ~8 weeks |
| Oct | 77°F | 81°F | 🔥 Peak | ~8 weeks |
| Nov | 67°F | 72°F | 🔥 Peak | ~8 weeks |
| Dec | 55°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 Napa 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 Napa 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 28 | Feb 12 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Sep 27 | Feb 5 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Oct 15 | Feb 12 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Sep 5 | Feb 12 | ✓ 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 1 | Oct 1 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Cowpeas (southern peas) | Mar 6 | Sep 24 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
| Sorghum-sudan grass | Feb 27 | Sep 17 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Jan 30 | Sep 17 | ✓ 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 28 | Oct 29 | — | 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: 11 mph
Fall: 9 mph Winter: 11 mph
Prevailing wind: W. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.2/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (717 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
17,394 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 2,250 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
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 34.9 inches of rain per year
- A 1,000 sq ft roof can collect roughly 17,394 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 Napa County
Soil Type
Loam
Soil pH 6.7–7.5 · Excessively Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 5.5/10
Moderate drought pressure. Drip irrigation and mulching are highly recommended to maintain soil moisture through summer.
Season Tips
274-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.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
🥬 Vegetables to Grow in Napa County
115 vegetables that grow well in Zone 9a with planting dates for Napa County.
Show all 115 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Jan 29 | Feb 26 | Mar 5 | May 28 – Jul 2 | 80–100 |
| Amaranth | Jan 15 | Feb 26 | Mar 5 | Jun 4 – Jul 23 | 90–120 |
| Artichoke | — | — | Mar 12 | Jul 16 – Sep 24 | 120–180 |
| Arugula | Jan 29 | Feb 5 | Feb 26 | Apr 2 – Jun 4 | 30–50 |
| Asparagus | — | — | Mar 12 | — | 730–1095 |
| Beets | — | Feb 5 | — | Apr 2 – Apr 30 | 50–70 |
| Belgian Endive | Jan 29 | Feb 5 | Feb 26 | Jun 18 – Aug 13 | 110–150 |
| Bitter Melon | Jan 15 | Feb 26 | Mar 5 | May 7 – Jun 18 | 60–90 |
| Black Beans | — | Mar 5 | — | Jun 4 – Jul 23 | 90–120 |
| Bok Choy | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 14 | 40–60 |
| Broccoli | Jan 29 | Feb 5 | Feb 26 | Apr 30 – Jun 11 | 60–90 |
| Broccoli Rabe | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 14 | 40–60 |
| Brussels Sprouts | Jan 29 | Feb 5 | Feb 26 | May 28 – Jul 23 | 90–130 |
| Butternut Squash | Jan 29 | Feb 26 | Mar 5 | Jun 4 – Jul 9 | 85–110 |
| Cabbage | Jan 29 | Feb 5 | Feb 26 | Apr 30 – Jun 25 | 60–100 |
| Calabash | Jan 15 | Feb 26 | Mar 5 | May 28 – Jul 23 | 80–120 |
| Cardoon | — | — | Mar 12 | Jul 16 – Aug 27 | 120–150 |
| Carrots | — | Feb 5 | — | Apr 9 – May 14 | 60–80 |
| Cauliflower | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 25 | 55–100 |
| Celeriac | Jan 29 | Feb 5 | Feb 26 | Jun 11 – Jul 16 | 100–120 |
| Celery | Jan 29 | Feb 5 | Feb 26 | May 21 – Jul 16 | 80–120 |
| Celtuce | Jan 29 | Feb 5 | Feb 26 | Apr 30 – Jun 11 | 60–90 |
| Chard | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 11 | 50–60 |
| Chayote | Jan 15 | Feb 26 | Mar 5 | Jul 9 – Sep 17 | 120–180 |
| Chickpeas | Jan 29 | Feb 5 | Feb 26 | May 21 – Jul 2 | 80–110 |
| Chicory | Jan 29 | Feb 5 | Feb 26 | Apr 30 – Jun 11 | 60–85 |
| Chinese Cabbage | Jan 29 | Feb 5 | Feb 26 | Apr 23 – May 21 | 50–70 |
| Christmas Lima Beans | Jan 15 | Feb 26 | Mar 5 | May 28 – Jul 2 | 80–100 |
| Collard Greens | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 25 | 55–75 |
| Corn | — | Mar 5 | — | May 7 – Jul 2 | 60–100 |
| Cowpeas | — | Mar 5 | — | May 7 – Jun 18 | 60–90 |
| Cress | Jan 29 | Feb 5 | Feb 26 | Mar 12 – Apr 2 | 14–21 |
| Crookneck Squash | Jan 29 | Feb 26 | Mar 5 | Apr 23 – May 21 | 45–60 |
| Crosne | — | Feb 5 | — | Jul 9 – Sep 10 | 150–200 |
| Cucumber | Jan 29 | Feb 26 | Mar 5 | Apr 30 – Jun 25 | 50–70 |
| Daikon | — | Feb 5 | — | Apr 2 – Apr 30 | 50–70 |
| Delicata Squash | Jan 29 | Feb 26 | Mar 5 | May 28 – Jul 2 | 80–100 |
| Edamame | — | Mar 5 | — | May 21 – Jul 2 | 75–100 |
| Eggplant | Jan 15 | Feb 26 | Mar 5 | May 14 – Jul 16 | 65–85 |
| Endive | Jan 29 | Feb 5 | Feb 26 | Apr 16 – May 21 | 45–65 |
| Escarole | Jan 29 | Feb 5 | Feb 26 | Apr 23 – May 21 | 50–70 |
| Fava Beans | Jan 29 | Feb 5 | Feb 26 | May 14 – Jun 25 | 75–100 |
| Fennel | Jan 15 | Feb 26 | Mar 5 | May 7 – Jun 18 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Ginger | Jan 15 | Feb 26 | Mar 5 | Nov 5 – Dec 31 | 240–300 |
| Green Beans | — | Mar 5 | — | Apr 30 – Jun 25 | 50–65 |
| Horseradish | — | — | Mar 12 | Jul 16 – Sep 24 | 120–180 |
| Hot Peppers | Jan 15 | Feb 26 | Mar 5 | May 14 – Aug 20 | 70–120 |
| Hubbard Squash | Jan 29 | Feb 26 | Mar 5 | Jun 18 – Jul 23 | 100–120 |
| Jicama | Jan 15 | Feb 26 | Mar 5 | Jul 9 – Sep 17 | 120–180 |
| Kabocha | Jan 29 | Feb 26 | Mar 5 | Jun 4 – Jul 2 | 85–100 |
| Kai Lan | Jan 29 | Feb 5 | Feb 26 | Apr 16 – May 14 | 45–60 |
| Kale | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 18 | 50–70 |
| Kidney Beans | — | Mar 5 | — | Jun 4 – Jul 9 | 85–110 |
| Kohlrabi | Jan 29 | Feb 5 | Feb 26 | Apr 16 – May 21 | 45–65 |
| Komatsuna | Jan 29 | Feb 5 | Feb 26 | Apr 2 – May 7 | 35–50 |
| Leeks | Jan 29 | Feb 5 | Feb 26 | May 28 – Aug 13 | 90–150 |
| Lentils | Jan 29 | Feb 5 | Feb 26 | May 21 – Jul 2 | 80–110 |
| Lettuce | Jan 29 | Feb 5 | Feb 26 | Apr 2 – Jun 11 | 30–60 |
| Lima Beans | — | Mar 5 | — | May 7 – Jun 18 | 60–90 |
| Loofah | Jan 15 | Feb 26 | Mar 5 | Jun 18 – Aug 20 | 100–150 |
| Luffa | Jan 15 | Feb 26 | Mar 5 | Jun 4 – Aug 20 | 90–150 |
| Mache | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 14 | 40–60 |
| Malabar Spinach | Jan 15 | Feb 26 | Mar 5 | Apr 30 – May 28 | 55–70 |
| Melon | Jan 29 | Feb 26 | Mar 5 | May 14 – Jul 2 | 70–100 |
| Microgreens | Jan 29 | Feb 5 | Feb 26 | Mar 5 – Apr 2 | 7–21 |
| Mitsuba | Jan 29 | Feb 5 | Feb 19 | Apr 16 – Jun 11 | 50–70 |
| Mizuna | Jan 29 | Feb 5 | Feb 26 | Apr 2 – Apr 30 | 30–45 |
| Mustard Greens | Jan 29 | Feb 5 | Feb 26 | Apr 2 – Jun 4 | 30–50 |
| Napa Cabbage | Jan 29 | Feb 5 | Feb 26 | Apr 23 – May 28 | 55–75 |
| New Zealand Spinach | Jan 15 | Feb 26 | Mar 5 | Apr 30 – May 28 | 55–70 |
| Okra | Jan 15 | Feb 26 | Mar 5 | Apr 30 – Jun 25 | 50–65 |
| Onion | Jan 29 | Feb 5 | Feb 26 | May 28 – Jul 16 | 90–120 |
| Pac Choi | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 7 | 40–55 |
| Parsnip | — | Feb 5 | — | May 21 – Jul 2 | 100–130 |
| Patty Pan Squash | Jan 29 | Feb 26 | Mar 5 | Apr 23 – May 21 | 45–60 |
| Peas | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 18 | 55–70 |
| Peppers | Jan 15 | Feb 26 | Mar 5 | May 7 – Jul 16 | 60–90 |
| Pole Beans | Jan 15 | Feb 26 | Mar 5 | Apr 30 – Jun 25 | 55–70 |
| Potatoes | Jan 15 | Feb 26 | Mar 5 | May 14 – Jul 23 | 70–120 |
| Pumpkin | Jan 29 | Feb 26 | Mar 5 | Jun 4 – Jul 23 | 85–120 |
| Purslane | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 14 | 40–60 |
| Radicchio | Jan 29 | Feb 5 | Feb 26 | Apr 30 – Jun 4 | 60–80 |
| Radish | — | Feb 5 | — | Mar 5 – Mar 26 | 22–35 |
| Romanesco | Jan 29 | Feb 5 | Feb 26 | May 14 – Jun 25 | 75–100 |
| Rutabaga | — | Feb 5 | — | Apr 30 – Jun 4 | 80–100 |
| Salsify | — | Feb 5 | — | May 21 – Jul 2 | 100–130 |
| Savoy Cabbage | Jan 29 | Feb 5 | Feb 26 | May 7 – Jul 2 | 70–110 |
| Scallions | Jan 29 | Feb 5 | Feb 26 | Apr 23 – May 21 | 50–70 |
| Scarlet Runner Beans | Jan 15 | Feb 26 | Mar 5 | May 7 – Jun 11 | 60–80 |
| Shallot | Jan 29 | Feb 5 | Feb 26 | May 28 – Jul 16 | 90–120 |
| Shiso | Jan 15 | Mar 5 | Mar 5 | Apr 30 – Jun 25 | 50–70 |
| Snap Peas | Jan 15 | Feb 26 | Mar 5 | Apr 30 – Jun 25 | 55–70 |
| Snow Peas | Jan 29 | Feb 5 | Feb 26 | Apr 23 – Jun 18 | 50–65 |
| Soybeans | — | Mar 5 | — | May 28 – Jul 23 | 80–120 |
| Spaghetti Squash | Jan 29 | Feb 26 | Mar 5 | Jun 4 – Jul 2 | 85–100 |
| Spinach | Jan 29 | Feb 5 | Feb 26 | Apr 2 – Jun 4 | 35–50 |
| Squash (Summer) | Jan 29 | Feb 26 | Mar 5 | Apr 23 – Jun 25 | 45–65 |
| Squash (Winter) | Jan 29 | Feb 26 | Mar 5 | May 28 – Jul 23 | 80–120 |
| Sunchoke | — | — | Mar 12 | Jul 2 – Aug 27 | 110–150 |
| Sunflower | Jan 15 | Feb 26 | Mar 5 | May 14 – Jul 2 | 70–100 |
| Sweet Corn | — | Mar 5 | — | May 7 – Jun 18 | 60–90 |
| Sweet Potatoes | Jan 15 | Feb 26 | Mar 5 | Jun 4 – Jul 23 | 90–120 |
| Tatsoi | Jan 29 | Feb 5 | Feb 26 | Apr 2 – May 7 | 35–50 |
| Tomatillo | Jan 15 | Feb 26 | Mar 5 | May 7 – Jul 16 | 60–85 |
| Tomatoes | Jan 15 | Feb 26 | Mar 5 | May 7 – Jul 16 | 60–85 |
| Turmeric | Jan 15 | Feb 26 | Mar 5 | Nov 5 – Dec 31 | 240–300 |
| Turnip | — | Feb 5 | — | Mar 19 – Apr 23 | 40–60 |
| Watercress | Jan 29 | Feb 5 | Feb 26 | Apr 9 – May 14 | 40–60 |
| Watermelon | Jan 29 | Feb 26 | Mar 5 | May 14 – Jul 2 | 70–100 |
| Wax Beans | — | Mar 5 | — | Apr 30 – Jun 25 | 50–65 |
| Winter Melon | Jan 15 | Feb 26 | Mar 5 | Jun 4 – Jul 23 | 90–120 |
| Yam | Jan 15 | Feb 26 | Mar 5 | Sep 3 – Dec 31 | 180–330 |
| Yard Long Beans | Jan 15 | Feb 26 | Mar 5 | Apr 30 – Jun 11 | 55–80 |
| Zucchini | Jan 29 | Feb 26 | Mar 5 | Apr 23 – Jun 18 | 45–60 |
🍓 Fruits to Grow in Napa County
24 fruits that grow well in Zone 9a with planting dates for Napa County.
Show all 24 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Mar 12 | Jun 11 – Sep 24 | 90–180 |
| Blackberries | — | — | Mar 12 | — | 365–730 |
| Boysenberries | — | — | Mar 12 | — | 365–730 |
| Cantaloupe | — | — | Mar 12 | May 21 – Jun 25 | 70–90 |
| Che Fruit | — | — | Mar 12 | — | 1095–1825 |
| Dragon Fruit | — | — | Mar 12 | — | 365–730 |
| Elderberries | — | — | Mar 12 | — | 730–1095 |
| Figs | — | — | Mar 12 | — | 730–1825 |
| Goji Berries | — | — | Mar 12 | — | 730–1095 |
| Grapes | — | — | Mar 12 | — | 730–1095 |
| Ground Cherry | — | — | Mar 12 | May 21 – Jul 16 | 65–80 |
| Guava | — | — | Mar 12 | — | 365–730 |
| Honeydew | — | — | Mar 12 | Jun 4 – Jul 16 | 80–110 |
| Kiwi | — | — | Mar 12 | — | 1095–1825 |
| Loquat | — | — | Mar 12 | — | 730–1825 |
| Mulberries | — | — | Mar 12 | — | 730–1825 |
| Passion Fruit | — | — | Mar 12 | — | 365–545 |
| Pawpaw | — | — | Mar 12 | — | 1095–2555 |
| Persimmon | — | — | Mar 12 | — | 1095–2555 |
| Pomegranate | — | — | Mar 12 | — | 730–1095 |
| Quince | — | — | Mar 12 | — | 1095–1825 |
| Raspberries | — | — | Mar 12 | — | 365–730 |
| Serviceberries | — | — | Mar 12 | — | 730–1095 |
| Strawberries | — | — | Mar 12 | Jun 11 – Jan 7 | 90–365 |
🌿 Herbs to Grow in Napa County
40 herbs that grow well in Zone 9a with planting dates for Napa County.
Show all 40 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Anise | Jan 29 | Feb 5 | Feb 19 | May 21 – Aug 6 | 90–120 |
| Basil | Jan 15 | Mar 5 | Mar 5 | Apr 30 – Jul 2 | 50–75 |
| Bee Balm | — | — | Mar 5 | Jun 4 – Aug 20 | 90–120 |
| Borage | Jan 29 | Feb 5 | Feb 19 | Apr 16 – Jun 4 | 50–60 |
| Caraway | Jan 29 | Feb 5 | Feb 19 | — | 365–450 |
| Catnip | — | — | Mar 5 | May 7 – Jul 9 | 60–80 |
| Chamomile | Jan 29 | Feb 5 | Feb 19 | Apr 23 – Jul 2 | 60–90 |
| Chervil | Jan 29 | Feb 5 | Feb 19 | Apr 2 – Jun 4 | 40–60 |
| Chives | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Cilantro | Jan 29 | Feb 5 | Feb 19 | Apr 2 – Jun 4 | 40–60 |
| Comfrey | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Cumin | Jan 29 | Feb 5 | Feb 19 | Jun 4 – Aug 6 | 100–120 |
| Dill | Jan 29 | Feb 5 | Feb 19 | Apr 2 – Jun 4 | 40–60 |
| Echinacea | — | — | Mar 5 | Jul 9 – Oct 15 | 120–180 |
| Epazote | Jan 15 | Mar 5 | Mar 5 | Apr 23 – Jun 18 | 45–60 |
| Fennel (herb) | Jan 29 | Feb 5 | Feb 19 | Apr 23 – Jul 2 | 60–90 |
| Feverfew | — | — | Mar 5 | Jun 4 – Aug 20 | 90–120 |
| Garlic Chives | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Horehound | — | — | Mar 5 | May 21 – Jul 16 | 75–90 |
| Hyssop | — | — | Mar 5 | May 14 – Jul 16 | 70–90 |
| Lavender | — | — | Mar 5 | Jun 4 – Nov 5 | 90–200 |
| Lemon Balm | — | — | Mar 5 | May 7 – Jun 25 | 60–70 |
| Lemon Thyme | — | — | Mar 5 | May 14 – Jul 16 | 70–90 |
| Lemon Verbena | Jan 15 | Mar 5 | Mar 5 | May 7 – Jul 16 | 60–90 |
| Lemongrass | Jan 15 | Mar 5 | Mar 5 | May 21 – Aug 20 | 75–120 |
| Marjoram | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Mint | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Oregano | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Parsley | Jan 29 | Feb 5 | Feb 19 | Apr 23 – Jun 25 | 60–80 |
| Rosemary | — | — | Mar 5 | May 28 – Oct 15 | 80–180 |
| Rue | — | — | Mar 5 | May 14 – Jul 16 | 70–90 |
| Sage | — | — | Mar 5 | May 21 – Jul 16 | 75–90 |
| Savory | — | — | Mar 5 | Apr 30 – Jun 25 | 50–70 |
| Sorrel | Jan 29 | Feb 5 | Feb 19 | Apr 2 – Jun 4 | 40–60 |
| Stevia | Jan 15 | Mar 5 | Mar 5 | May 7 – Jul 16 | 60–90 |
| Tarragon | — | — | Mar 5 | May 7 – Jul 16 | 60–90 |
| Thai Basil | Jan 15 | Mar 5 | Mar 5 | Apr 30 – Jul 2 | 50–75 |
| Thyme | — | — | Mar 5 | May 14 – Jul 16 | 70–90 |
| Valerian | — | — | Mar 5 | Jul 9 – Oct 15 | 120–180 |
| Yarrow | — | — | Mar 5 | Jun 4 – Aug 20 | 90–120 |
Monthly Planting Guide for Napa County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Napa County.
Frequently Asked Questions
What planting zone is Napa County, CA?
Napa 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 Napa County, CA?
Based on 30 years of NOAA weather station data, the median last spring frost in Napa County falls around February 26. In 8 out of 10 years, last frost lands between January 13 and April 2 — a 79-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 Napa County, CA?
The median first fall frost in Napa County arrives around November 26. In cold years it can arrive as early as November 9; in mild years as late as December 17. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Napa County?
Napa County has a frost-free growing season of approximately 274 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 Napa County for gardening?
Napa County has predominantly Loam soil with a pH range of 6.7–7.5 and Excessively Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Napa County?
Napa County has commercial agriculture that includes Almonds, Dairy, Grapes, Lettuce, Walnuts. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Napa County a good location for home gardening?
Napa County scores 72/100 (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.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Napa 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.
