Contra Costa County, CA — Planting Guide
June in Contra Costa County, California — your action list
Here's what deserves your attention in Contra Costa County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.
-
Collect basil, cucumber, and green beans at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Get ahead of July
- First harvests: basil, peppers, and thai basil
Contra Costa County is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 277 days.
At an elevation of 88 ft, Contra Costa County receives approximately 19 in of rainfall annually. Summer highs average 93°F with winter lows around 53°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. Contra Costa County scores 61/100 (Good) on the Microclimate Index.
🌡️ Zone
9b (25°F to 30°F min)
❄️ Last Frost
February 26
🍂 First Frost
November 29
📅 Growing Season
277 days
⛰️ Elevation
88 ft
🌧️ Annual Rainfall
19 in
Monthly Watering Calendar for Contra Costa County
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
For new gardeners: In humid climates, watering is usually about timing (morning, not evening, to prevent disease) more than volume. In dry climates, it's about depth (water deep, less often) more than frequency. Contra Costa County's 19" annual tells you which side you're on.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 4.1 in | 11 days | — | None |
| Feb | 4.5 in | 10 days | — | Low |
| Mar | 3 in | 8 days | 1.3 in | Moderate |
| Apr | 1.5 in | 5 days | 2.8 in | High |
| May | 0.6 in | 2 days | 3.7 in | Critical |
| Jun | 0.1 in | 0 days | 4.2 in | Critical |
| Jul | 0 in | 0 days | 4.3 in | Critical |
| Aug | 0 in | 0 days | 4.3 in | Critical |
| Sep | 0.2 in | 1 days | 4.1 in | Critical |
| Oct | 0.7 in | 2 days | 3.6 in | Critical |
| Nov | 1.6 in | 6 days | 2.7 in | High |
| Dec | 2.7 in | 9 days | — | None |
Annual total: 19 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.
Contra Costa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
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 19 | 261 days |
| Cautious | Mar 7 | Dec 6 | 274 days |
| Average year | Feb 26 | Nov 29 | 276 days |
| Optimistic | Feb 5 | Nov 23 | 291 days |
| Aggressive (risky) | Jan 13 | Nov 10 | 301 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
Contra Costa County offers good growing conditions. A little planning around frost dates goes a long way.
Local Gardening Help in Contra Costa 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 Contra Costa County's climate and soil.
County Extension Office
Contra Costa 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 Contra Costa County
Finding local nurseries & garden centers in Contra Costa County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Contra Costa 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 Contra Costa County CA" or "garden center Contra Costa 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 Contra Costa County CA" or check your extension office and local parks department. Facebook groups like "Contra Costa 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 in Contra Costa County
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Why it matters: A 14-hour day in June produces dramatically more photosynthesis than a 10-hour day in November. Contra Costa County's seasonal swing determines which crops can pack growth into spring vs. limp through fall.
Longest Day
14.6 hours
Summer solstice daylight
Shortest Day
9.4 hours
Winter solstice daylight
Peak Sun Hours
13.3 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 | 5.7 hr | Short day |
| February | 10.6 hr | 6.6 hr | Short day |
| March | 11.7 hr | 7.9 hr | Short day |
| April | 13 hr | 9.6 hr | Neutral |
| May | 14 hr | 11.3 hr | Long day |
| June | 14.6 hr | 13.3 hr | Long day |
| July | 14.4 hr | 13.3 hr | Long day |
| August | 13.5 hr | 12.7 hr | Neutral |
| September | 12.2 hr | 10.9 hr | Neutral |
| October | 11 hr | 8.3 hr | Short day |
| November | 9.9 hr | 6.3 hr | Short day |
| December | 9.4 hr | 5 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting in Contra Costa County
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
What this means for you: Mulched soil swings less. The mulch insulates against both winter cold and summer heat. In Contra Costa County, an aggressive mulch program shifts your effective soil temperature curve toward optimal for most crops.
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 | 52°F | 59°F | ♻️ Active | ~14 weeks |
| Feb | 54°F | 58°F | ♻️ Active | ~14 weeks |
| Mar | 59°F | 62°F | ♻️ Active | ~14 weeks |
| Apr | 67°F | 68°F | 🔥 Peak | ~8 weeks |
| May | 78°F | 74°F | 🔥 Peak | ~8 weeks |
| Jun | 87°F | 81°F | 🔥 Peak | ~8 weeks |
| Jul | 95°F | 88°F | 🔥 Peak | ~8 weeks |
| Aug | 95°F | 89°F | 🔥 Peak | ~8 weeks |
| Sep | 89°F | 89°F | 🔥 Peak | ~8 weeks |
| Oct | 78°F | 79°F | 🔥 Peak | ~8 weeks |
| Nov | 65°F | 72°F | 🔥 Peak | ~8 weeks |
| Dec | 54°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 Contra Costa County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
For new gardeners: In Contra Costa County's climate, pest pressure shapes which crops are easy and which are heartbreak. Tomatoes are easy in dry mountain air, hard in humid coast — same plant, completely different gardening experience.
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 | Moderate | 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 Contra Costa County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.
For new gardeners: Cover crops fix nitrogen by hosting bacteria that pull it from the air. A vigorous legume cover crop can deliver 50-150 lbs/acre of nitrogen — meaningful for the next vegetable season.
Spring Cover Crops (4 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Mar 4 | Sep 27 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Cowpeas (southern peas) | Mar 3 | Oct 4 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
| Sorghum-sudan grass | Mar 2 | Sep 27 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Jan 27 | Sep 20 | ✓ 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 15 | — | Deep roots break compaction, attract pollinators and beneficial insects |
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 23 | Feb 12 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Sep 23 | Feb 5 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Oct 19 | Feb 12 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Sep 6 | Feb 5 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
Wind & Microclimate in Contra Costa County
Quick context: Wind is the silent water thief. Every breeze pulls moisture from leaves and soil. Contra Costa County's 10.9 mph average is one piece of the watering math: rainfall + irrigation must exceed evaporation + transpiration, and wind boosts both losses.
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 11 mph Summer: 11 mph
Fall: 9 mph Winter: 9 mph
Prevailing wind: W. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.1/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (878 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.
Rainwater Harvesting in Contra Costa County
How much water you can collect, when to collect it, and what size system you need for your garden.
What this means for you: Most gardens use 0.5-1 gallon per square foot per week in summer. Contra Costa County's 19" annual rainfall is enough to cover most needs if you can capture it. Rain barrels under downspouts are the simplest entry point.
Annual Collection
9,469 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
8 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, 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 19.0 inches of rain per year
- A 1,000 sq ft roof can collect roughly 9,469 gallons annually
- Rainwater harvesting is fully legal in your state
- In your dry climate, every drop counts — consider a larger cistern system
- Position collection tanks in shade to reduce evaporation and algae growth
Soil & Growing Conditions in Contra Costa County
Soil Type
Loam
Soil pH 6.7–7.8 · Well Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 7.5/10
High drought stress. Consistent irrigation is essential — consider drip systems, heavy mulch, and drought-tolerant varieties.
Season Tips
277-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.
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.
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 Contra Costa County
114 vegetables that grow well in Zone 9b with planting dates for Contra Costa County.
Show all 114 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | 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 | Oct 4 | Apr 2 – Jun 4 | 30–50 |
| Asparagus | — | — | Mar 12 | — | — | 730–1095 |
| Beets | — | Feb 5 | — | Oct 4 | Apr 2 – Apr 30 | 50–70 |
| Belgian Endive | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | Apr 9 – May 14 | 40–60 |
| Broccoli | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 30 – Jun 11 | 60–90 |
| Broccoli Rabe | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 9 – May 14 | 40–60 |
| Brussels Sprouts | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | 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 | — | Oct 4 | Apr 9 – May 14 | 60–80 |
| Cauliflower | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 23 – Jun 25 | 55–100 |
| Celeriac | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Jun 11 – Jul 16 | 100–120 |
| Celery | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 21 – Jul 16 | 80–120 |
| Celtuce | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 30 – Jun 11 | 60–90 |
| Chard | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | May 21 – Jul 2 | 80–110 |
| Chicory | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 30 – Jun 11 | 60–85 |
| Chinese Cabbage | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | 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 | Oct 4 | Mar 12 – Apr 2 | 14–21 |
| Crookneck Squash | Jan 29 | Feb 26 | Mar 5 | — | Apr 23 – May 21 | 45–60 |
| Crosne | — | Feb 5 | — | Oct 4 | Jul 9 – Sep 10 | 150–200 |
| Cucumber | Jan 29 | Feb 26 | Mar 5 | — | Apr 30 – Jun 25 | 50–70 |
| Daikon | — | Feb 5 | — | Oct 4 | 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 | Oct 4 | Apr 16 – May 21 | 45–65 |
| Escarole | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 23 – May 21 | 50–70 |
| Fava Beans | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 14 – Jun 25 | 75–100 |
| Fennel | Jan 15 | Feb 26 | Mar 5 | — | May 7 – Jun 18 | 60–90 |
| Garlic | — | — | — | Oct 18 | Jan 17 – Jul 4 | 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 | Oct 4 | Apr 16 – May 14 | 45–60 |
| Kale | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 23 – Jun 18 | 50–70 |
| Kidney Beans | — | Mar 5 | — | — | Jun 4 – Jul 9 | 85–110 |
| Kohlrabi | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 16 – May 21 | 45–65 |
| Komatsuna | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 2 – May 7 | 35–50 |
| Leeks | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 28 – Aug 13 | 90–150 |
| Lentils | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 21 – Jul 2 | 80–110 |
| Lettuce | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | 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 | Oct 4 | Mar 5 – Apr 2 | 7–21 |
| Mitsuba | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Apr 16 – Jun 11 | 50–70 |
| Mizuna | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 2 – Apr 30 | 30–45 |
| Mustard Greens | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 2 – Jun 4 | 30–50 |
| Napa Cabbage | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | May 28 – Jul 16 | 90–120 |
| Pac Choi | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 9 – May 7 | 40–55 |
| Parsnip | — | Feb 5 | — | Oct 4 | 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 | Oct 4 | 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 | Oct 4 | Apr 9 – May 14 | 40–60 |
| Radicchio | Jan 29 | Feb 5 | Feb 26 | Oct 4 | Apr 30 – Jun 4 | 60–80 |
| Radish | — | Feb 5 | — | Oct 4 | Mar 5 – Mar 26 | 22–35 |
| Romanesco | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 14 – Jun 25 | 75–100 |
| Rutabaga | — | Feb 5 | — | Oct 4 | Apr 30 – Jun 4 | 80–100 |
| Salsify | — | Feb 5 | — | Oct 4 | May 21 – Jul 2 | 100–130 |
| Savoy Cabbage | Jan 29 | Feb 5 | Feb 26 | Oct 4 | May 7 – Jul 2 | 70–110 |
| Scallions | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 | Oct 4 | 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 | Oct 4 | 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 | Oct 4 | 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 |
| 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 | Oct 4 | 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 | — | Oct 4 | Mar 19 – Apr 23 | 40–60 |
| Watercress | Jan 29 | Feb 5 | Feb 26 | Oct 4 | 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 Contra Costa County
24 fruits that grow well in Zone 9b with planting dates for Contra Costa County.
Show all 24 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | 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 Contra Costa County
37 herbs that grow well in Zone 9b with planting dates for Contra Costa County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Harvest | Days to Maturity |
|---|---|---|---|---|---|---|
| Anise | Jan 29 | Feb 5 | Feb 19 | Oct 4 | 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 | Oct 4 | Apr 16 – Jun 4 | 50–60 |
| Caraway | Jan 29 | Feb 5 | Feb 19 | Oct 4 | — | 365–450 |
| Catnip | — | — | Mar 5 | — | May 7 – Jul 9 | 60–80 |
| Chamomile | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Apr 23 – Jul 2 | 60–90 |
| Chervil | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Apr 2 – Jun 4 | 40–60 |
| Chives | — | — | Mar 5 | — | May 7 – Jul 16 | 60–90 |
| Cilantro | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Apr 2 – Jun 4 | 40–60 |
| Comfrey | — | — | Mar 5 | — | May 7 – Jul 16 | 60–90 |
| Cumin | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Jun 4 – Aug 6 | 100–120 |
| Dill | Jan 29 | Feb 5 | Feb 19 | Oct 4 | Apr 2 – Jun 4 | 40–60 |
| Epazote | Jan 15 | Mar 5 | Mar 5 | — | Apr 23 – Jun 18 | 45–60 |
| Fennel (herb) | Jan 29 | Feb 5 | Feb 19 | Oct 4 | 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 |
| 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 | Oct 4 | 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 | Oct 4 | 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 |
🌸 Flowers to Grow in Contra Costa County
42 flowers that grow well in Zone 9b with planting dates for Contra Costa County.
Show all 42 flowers with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Fall Plant | Bloom | Days to Maturity |
|---|---|---|---|---|---|---|
| Ageratum | Jan 15 | Feb 5 | Feb 5 | — | Apr 2 – Oct 1 | 60–75 |
| Alliums | — | — | — | Nov 8 | Dec 6 – Dec 27 | 28–42 |
| Anemones | — | — | — | Oct 18 | Oct 18 – Nov 15 | 90–120 |
| Bachelor's Button | — | Dec 25 | Jan 22 | Sep 20 | Mar 19 – Jul 9 | 60–90 |
| Begonias | Dec 18 | — | Jan 29 | — | Apr 9 – Oct 22 | 70–90 |
| Black-eyed Susan | Jan 1 | Feb 5 | Feb 12 | — | Apr 23 – Sep 10 | 60–80 |
| Calendula | — | Dec 25 | Jan 22 | Sep 6 | Mar 5 – Jun 25 | 50–70 |
| California Poppy | — | — | — | Aug 23 | Nov 1 – Mar 7 | 60–90 |
| Celosia | Jan 29 | Feb 5 | Feb 5 | — | Apr 9 – Oct 29 | 60–90 |
| Coreopsis | Jan 1 | Feb 5 | Feb 12 | — | Apr 9 – Sep 10 | 60–80 |
| Cosmos | Jan 29 | Jan 22 | Jan 22 | — | Apr 2 – Oct 1 | 60–90 |
| Daffodils | — | — | — | Nov 1 | Oct 18 – Nov 8 | 20–40 |
| Dahlias | — | Feb 26 | Feb 26 | — | May 7 – Nov 19 | 70–120 |
| Daylily | Jan 1 | — | Feb 12 | — | Apr 23 – Oct 22 | 60–90 |
| Dianthus | Jan 1 | Dec 25 | Dec 25 | — | Feb 12 – Apr 9 | 60–80 |
| Echinacea (Purple Coneflower) | Jan 1 | Feb 12 | Feb 12 | — | Apr 23 – Sep 10 | 70–90 |
| Freesia | — | — | — | Oct 18 | Oct 25 – Nov 29 | 84–112 |
| Gaillardia (Blanket Flower) | Jan 15 | Feb 5 | Feb 5 | — | Apr 16 – Oct 15 | 70–100 |
| Geraniums | Dec 18 | — | Jan 29 | — | Apr 9 – Oct 22 | 70–100 |
| Gladiolus | — | Feb 26 | Feb 26 | — | May 7 – Nov 19 | 70–100 |
| Hyacinths | — | — | — | Nov 8 | Nov 8 – Nov 29 | 14–28 |
| Impatiens | Jan 1 | — | Feb 5 | — | Apr 16 – Oct 15 | 60–75 |
| Irises | — | Division | Feb 5 | — | Mar 26 – Apr 30 | 60–100 |
| Larkspur | — | — | — | Sep 27 | Dec 6 – Mar 14 | 60–90 |
| Lavender | Jan 1 | — | Feb 5 | — | Apr 16 – Jul 9 | 90–120 |
| Lobelia | Jan 1 | — | Dec 25 | — | Feb 19 – Mar 19 | 70–80 |
| Marigolds | Jan 22 | Feb 5 | Feb 5 | — | Apr 2 – Sep 24 | 50–70 |
| Nasturtium | Jan 29 | Jan 29 | Jan 29 | — | Mar 26 – Oct 8 | 55–65 |
| Pansy | Dec 18 | — | Jan 22 | Sep 6 | Mar 12 – May 28 | 70–90 |
| Petunia | Jan 1 | — | Feb 5 | — | Apr 16 – Oct 1 | 70–90 |
| Portulaca | Jan 29 | Feb 5 | Feb 5 | — | Mar 26 – Oct 15 | 50–70 |
| Ranunculus | — | — | — | Oct 18 | Oct 25 – Nov 22 | 90–120 |
| Roses | Jan 1 | — | Feb 5 | — | Apr 16 – Oct 15 | 90–180 |
| Salvia | Jan 1 | — | Jan 29 | — | Apr 9 – Oct 8 | 70–90 |
| Sedum (Stonecrop) | Jan 1 | — | Feb 5 | — | May 28 – Aug 6 | 60–90 |
| Snapdragon | — | Dec 25 | Jan 22 | Sep 6 | Mar 26 – Aug 6 | 70–100 |
| Sunflower | Feb 5 | Jan 29 | Jan 29 | — | Apr 23 – Oct 8 | 70–100 |
| Sweet Alyssum | — | Dec 25 | Jan 22 | Sep 20 | Feb 26 – May 28 | 45–60 |
| Sweet Pea | — | — | — | Sep 20 | Nov 29 – Jan 10 | 65–85 |
| Vinca (Annual) | Dec 18 | — | Jan 29 | — | Apr 9 – Oct 22 | 70–90 |
| Yarrow | Jan 1 | Feb 5 | Feb 12 | — | Apr 9 – Aug 13 | 60–90 |
| Zinnia | Jan 29 | Jan 29 | Jan 29 | — | Apr 9 – Oct 8 | 60–70 |
Monthly Planting Guide for Contra Costa County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Contra Costa County.
Frequently Asked Questions
What planting zone is Contra Costa County, CA?
Contra Costa County is in USDA Hardiness Zone 9b. 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 Contra Costa County, CA?
Based on 30 years of NOAA weather station data, the median last spring frost in Contra Costa 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 Contra Costa County, CA?
The median first fall frost in Contra Costa County arrives around November 29. In cold years it can arrive as early as November 10; in mild years as late as December 19. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Contra Costa County?
Contra Costa County has a frost-free growing season of approximately 277 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 Contra Costa County for gardening?
Contra Costa County has predominantly Loam soil with a pH range of 6.7–7.8 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Contra Costa County?
Contra Costa County has commercial agriculture that includes Almonds, Grapes, Dairy, Tomatoes, Lettuce. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Contra Costa County a good location for home gardening?
Contra Costa County scores 61/100 (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.
Your Contra Costa County Garden Planner — Free
A 22-page printable planner built for Contra Costa County (Zone 9b). 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