Glenn County, CA — Planting Guide
Glenn County is in USDA Zone 9a. The average last spring frost is March 6 and the first fall frost is November 28, giving you a growing season of approximately 267 days.
At an elevation of 270 ft, Glenn County receives approximately 27.1 in of rainfall annually. Summer highs average 88°F with winter lows around 55°F. The predominant soil type is Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 95 days year to year — ranging from January 14 in warm years to April 18 in cold years. The growing season is trending longer by about 10.14 days per decade. Glenn County scores 51/100 (Moderate) on the Microclimate Index.
🌡️ Zone
9a (20°F to 25°F min)
❄️ Last Frost
March 6
🍂 First Frost
November 28
📅 Growing Season
267 days
⛰️ Elevation
270 ft
🌧️ Annual Rainfall
27.1 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 | 5.6 in | 11 days | — | None |
| Feb | 5.3 in | 10 days | — | Low |
| Mar | 4.4 in | 8 days | — | Low |
| Apr | 2.5 in | 4 days | 1.8 in | High |
| May | 0.7 in | 1 days | 3.6 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 | 0.3 in | 0 days | 4 in | Critical |
| Oct | 1.3 in | 3 days | 3 in | High |
| Nov | 2.5 in | 6 days | 1.8 in | High |
| Dec | 4.3 in | 9 days | — | None |
Annual total: 27 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.
Glenn County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.9
Drainage
Well Drained
Frost Risk Probability
Based on 31 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 18 | Dec 19 | 245 days |
| Cautious | Apr 2 | Dec 3 | 245 days |
| Average year | Mar 6 | Nov 28 | 267 days |
| Optimistic | Feb 23 | Nov 20 | 270 days |
| Aggressive (risky) | Jan 14 | Nov 8 | 298 days |
Not very — frost dates can vary by ±95 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Yes — growing seasons are getting longer here (about 10.1 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
Glenn County presents some gardening challenges. Choose adapted varieties and plan around frost dates.
Local Gardening Help in Glenn 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 Glenn County's climate and soil.
County Extension Office
Glenn 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 Glenn County
Finding local nurseries & garden centers in Glenn County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Glenn 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 Glenn County CA" or "garden center Glenn 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 Glenn County CA" or check your extension office and local parks department. Facebook groups like "Glenn 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
14.8 hours
Summer solstice daylight
Shortest Day
9.2 hours
Winter solstice daylight
Peak Sun Hours
14 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 | 9.5 hr | 5.5 hr | Short day |
| February | 10.5 hr | 6.6 hr | Short day |
| March | 11.7 hr | 7.4 hr | Short day |
| April | 13.1 hr | 9.7 hr | Neutral |
| May | 14.2 hr | 11.4 hr | Long day |
| June | 14.8 hr | 13.5 hr | Long day |
| July | 14.5 hr | 14 hr | Long day |
| August | 13.6 hr | 11.9 hr | Neutral |
| September | 12.2 hr | 10.3 hr | Neutral |
| October | 10.9 hr | 8 hr | Short day |
| November | 9.8 hr | 6 hr | Short day |
| December | 9.2 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 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 | 58°F | ♻️ Active | ~14 weeks |
| Feb | 51°F | 57°F | ♻️ Active | ~14 weeks |
| Mar | 59°F | 62°F | ♻️ Active | ~14 weeks |
| Apr | 68°F | 66°F | 🔥 Peak | ~8 weeks |
| May | 75°F | 73°F | 🔥 Peak | ~8 weeks |
| Jun | 85°F | 81°F | 🔥 Peak | ~8 weeks |
| Jul | 95°F | 89°F | 🔥 Peak | ~8 weeks |
| Aug | 96°F | 91°F | 🔥 Peak | ~8 weeks |
| Sep | 89°F | 87°F | 🔥 Peak | ~8 weeks |
| Oct | 80°F | 82°F | 🔥 Peak | ~8 weeks |
| Nov | 66°F | 73°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 Glenn 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 Glenn County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Spring Cover Crops (4 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Mar 17 | Sep 26 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Cowpeas (southern peas) | Mar 10 | Oct 3 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
| Sorghum-sudan grass | Mar 14 | Oct 3 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Feb 7 | Sep 19 | ✓ 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 20 | Nov 7 | — | 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 27 | Feb 13 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Oct 4 | Feb 13 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Oct 9 | Feb 13 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Sep 18 | Feb 13 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 12 mph Summer: 12 mph
Fall: 7 mph Winter: 11 mph
Prevailing wind: W. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (925 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
13,456 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 2,250 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 27.0 inches of rain per year
- A 1,000 sq ft roof can collect roughly 13,456 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 Glenn County
Soil Type
Loam
Soil pH 6.5–7.9 · Moderately 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
267-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 Glenn County
115 vegetables that grow well in Zone 9a with planting dates for Glenn County.
Show all 115 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Feb 6 | Mar 6 | Mar 13 | Jun 5 – Jul 10 | 80–100 |
| Amaranth | Jan 23 | Mar 6 | Mar 13 | Jun 12 – Jul 31 | 90–120 |
| Artichoke | — | — | Mar 20 | Jul 24 – Oct 2 | 120–180 |
| Arugula | Feb 6 | Feb 13 | Mar 6 | Apr 10 – Jun 12 | 30–50 |
| Asparagus | — | — | Mar 20 | — | 730–1095 |
| Beets | — | Feb 13 | — | Apr 10 – May 8 | 50–70 |
| Belgian Endive | Feb 6 | Feb 13 | Mar 6 | Jun 26 – Aug 21 | 110–150 |
| Bitter Melon | Jan 23 | Mar 6 | Mar 13 | May 15 – Jun 26 | 60–90 |
| Black Beans | — | Mar 13 | — | Jun 12 – Jul 31 | 90–120 |
| Bok Choy | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 22 | 40–60 |
| Broccoli | Feb 6 | Feb 13 | Mar 6 | May 8 – Jun 19 | 60–90 |
| Broccoli Rabe | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 22 | 40–60 |
| Brussels Sprouts | Feb 6 | Feb 13 | Mar 6 | Jun 5 – Jul 31 | 90–130 |
| Butternut Squash | Feb 6 | Mar 6 | Mar 13 | Jun 12 – Jul 17 | 85–110 |
| Cabbage | Feb 6 | Feb 13 | Mar 6 | May 8 – Jul 3 | 60–100 |
| Calabash | Jan 23 | Mar 6 | Mar 13 | Jun 5 – Jul 31 | 80–120 |
| Cardoon | — | — | Mar 20 | Jul 24 – Sep 4 | 120–150 |
| Carrots | — | Feb 13 | — | Apr 17 – May 22 | 60–80 |
| Cauliflower | Feb 6 | Feb 13 | Mar 6 | May 1 – Jul 3 | 55–100 |
| Celeriac | Feb 6 | Feb 13 | Mar 6 | Jun 19 – Jul 24 | 100–120 |
| Celery | Feb 6 | Feb 13 | Mar 6 | May 29 – Jul 24 | 80–120 |
| Celtuce | Feb 6 | Feb 13 | Mar 6 | May 8 – Jun 19 | 60–90 |
| Chard | Feb 6 | Feb 13 | Mar 6 | May 1 – Jun 19 | 50–60 |
| Chayote | Jan 23 | Mar 6 | Mar 13 | Jul 17 – Sep 25 | 120–180 |
| Chickpeas | Feb 6 | Feb 13 | Mar 6 | May 29 – Jul 10 | 80–110 |
| Chicory | Feb 6 | Feb 13 | Mar 6 | May 8 – Jun 19 | 60–85 |
| Chinese Cabbage | Feb 6 | Feb 13 | Mar 6 | May 1 – May 29 | 50–70 |
| Christmas Lima Beans | Jan 23 | Mar 6 | Mar 13 | Jun 5 – Jul 10 | 80–100 |
| Collard Greens | Feb 6 | Feb 13 | Mar 6 | May 1 – Jul 3 | 55–75 |
| Corn | — | Mar 13 | — | May 15 – Jul 10 | 60–100 |
| Cowpeas | — | Mar 13 | — | May 15 – Jun 26 | 60–90 |
| Cress | Feb 6 | Feb 13 | Mar 6 | Mar 20 – Apr 10 | 14–21 |
| Crookneck Squash | Feb 6 | Mar 6 | Mar 13 | May 1 – May 29 | 45–60 |
| Crosne | — | Feb 13 | — | Jul 17 – Sep 18 | 150–200 |
| Cucumber | Feb 6 | Mar 6 | Mar 13 | May 8 – Jul 3 | 50–70 |
| Daikon | — | Feb 13 | — | Apr 10 – May 8 | 50–70 |
| Delicata Squash | Feb 6 | Mar 6 | Mar 13 | Jun 5 – Jul 10 | 80–100 |
| Edamame | — | Mar 13 | — | May 29 – Jul 10 | 75–100 |
| Eggplant | Jan 23 | Mar 6 | Mar 13 | May 22 – Jul 24 | 65–85 |
| Endive | Feb 6 | Feb 13 | Mar 6 | Apr 24 – May 29 | 45–65 |
| Escarole | Feb 6 | Feb 13 | Mar 6 | May 1 – May 29 | 50–70 |
| Fava Beans | Feb 6 | Feb 13 | Mar 6 | May 22 – Jul 3 | 75–100 |
| Fennel | Jan 23 | Mar 6 | Mar 13 | May 15 – Jun 26 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Ginger | Jan 23 | Mar 6 | Mar 13 | Nov 13 – Jan 8 | 240–300 |
| Green Beans | — | Mar 13 | — | May 8 – Jul 3 | 50–65 |
| Horseradish | — | — | Mar 20 | Jul 24 – Oct 2 | 120–180 |
| Hot Peppers | Jan 23 | Mar 6 | Mar 13 | May 22 – Aug 28 | 70–120 |
| Hubbard Squash | Feb 6 | Mar 6 | Mar 13 | Jun 26 – Jul 31 | 100–120 |
| Jicama | Jan 23 | Mar 6 | Mar 13 | Jul 17 – Sep 25 | 120–180 |
| Kabocha | Feb 6 | Mar 6 | Mar 13 | Jun 12 – Jul 10 | 85–100 |
| Kai Lan | Feb 6 | Feb 13 | Mar 6 | Apr 24 – May 22 | 45–60 |
| Kale | Feb 6 | Feb 13 | Mar 6 | May 1 – Jun 26 | 50–70 |
| Kidney Beans | — | Mar 13 | — | Jun 12 – Jul 17 | 85–110 |
| Kohlrabi | Feb 6 | Feb 13 | Mar 6 | Apr 24 – May 29 | 45–65 |
| Komatsuna | Feb 6 | Feb 13 | Mar 6 | Apr 10 – May 15 | 35–50 |
| Leeks | Feb 6 | Feb 13 | Mar 6 | Jun 5 – Aug 21 | 90–150 |
| Lentils | Feb 6 | Feb 13 | Mar 6 | May 29 – Jul 10 | 80–110 |
| Lettuce | Feb 6 | Feb 13 | Mar 6 | Apr 10 – Jun 19 | 30–60 |
| Lima Beans | — | Mar 13 | — | May 15 – Jun 26 | 60–90 |
| Loofah | Jan 23 | Mar 6 | Mar 13 | Jun 26 – Aug 28 | 100–150 |
| Luffa | Jan 23 | Mar 6 | Mar 13 | Jun 12 – Aug 28 | 90–150 |
| Mache | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 22 | 40–60 |
| Malabar Spinach | Jan 23 | Mar 6 | Mar 13 | May 8 – Jun 5 | 55–70 |
| Melon | Feb 6 | Mar 6 | Mar 13 | May 22 – Jul 10 | 70–100 |
| Microgreens | Feb 6 | Feb 13 | Mar 6 | Mar 13 – Apr 10 | 7–21 |
| Mitsuba | Feb 6 | Feb 13 | Feb 27 | Apr 24 – Jun 19 | 50–70 |
| Mizuna | Feb 6 | Feb 13 | Mar 6 | Apr 10 – May 8 | 30–45 |
| Mustard Greens | Feb 6 | Feb 13 | Mar 6 | Apr 10 – Jun 12 | 30–50 |
| Napa Cabbage | Feb 6 | Feb 13 | Mar 6 | May 1 – Jun 5 | 55–75 |
| New Zealand Spinach | Jan 23 | Mar 6 | Mar 13 | May 8 – Jun 5 | 55–70 |
| Okra | Jan 23 | Mar 6 | Mar 13 | May 8 – Jul 3 | 50–65 |
| Onion | Feb 6 | Feb 13 | Mar 6 | Jun 5 – Jul 24 | 90–120 |
| Pac Choi | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 15 | 40–55 |
| Parsnip | — | Feb 13 | — | May 29 – Jul 10 | 100–130 |
| Patty Pan Squash | Feb 6 | Mar 6 | Mar 13 | May 1 – May 29 | 45–60 |
| Peas | Feb 6 | Feb 13 | Mar 6 | May 1 – Jun 26 | 55–70 |
| Peppers | Jan 23 | Mar 6 | Mar 13 | May 15 – Jul 24 | 60–90 |
| Pole Beans | Jan 23 | Mar 6 | Mar 13 | May 8 – Jul 3 | 55–70 |
| Potatoes | Jan 23 | Mar 6 | Mar 13 | May 22 – Jul 31 | 70–120 |
| Pumpkin | Feb 6 | Mar 6 | Mar 13 | Jun 12 – Jul 31 | 85–120 |
| Purslane | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 22 | 40–60 |
| Radicchio | Feb 6 | Feb 13 | Mar 6 | May 8 – Jun 12 | 60–80 |
| Radish | — | Feb 13 | — | Mar 13 – Apr 3 | 22–35 |
| Romanesco | Feb 6 | Feb 13 | Mar 6 | May 22 – Jul 3 | 75–100 |
| Rutabaga | — | Feb 13 | — | May 8 – Jun 12 | 80–100 |
| Salsify | — | Feb 13 | — | May 29 – Jul 10 | 100–130 |
| Savoy Cabbage | Feb 6 | Feb 13 | Mar 6 | May 15 – Jul 10 | 70–110 |
| Scallions | Feb 6 | Feb 13 | Mar 6 | May 1 – May 29 | 50–70 |
| Scarlet Runner Beans | Jan 23 | Mar 6 | Mar 13 | May 15 – Jun 19 | 60–80 |
| Shallot | Feb 6 | Feb 13 | Mar 6 | Jun 5 – Jul 24 | 90–120 |
| Shiso | Jan 23 | Mar 13 | Mar 13 | May 8 – Jul 3 | 50–70 |
| Snap Peas | Jan 23 | Mar 6 | Mar 13 | May 8 – Jul 3 | 55–70 |
| Snow Peas | Feb 6 | Feb 13 | Mar 6 | May 1 – Jun 26 | 50–65 |
| Soybeans | — | Mar 13 | — | Jun 5 – Jul 31 | 80–120 |
| Spaghetti Squash | Feb 6 | Mar 6 | Mar 13 | Jun 12 – Jul 10 | 85–100 |
| Spinach | Feb 6 | Feb 13 | Mar 6 | Apr 10 – Jun 12 | 35–50 |
| Squash (Summer) | Feb 6 | Mar 6 | Mar 13 | May 1 – Jul 3 | 45–65 |
| Squash (Winter) | Feb 6 | Mar 6 | Mar 13 | Jun 5 – Jul 31 | 80–120 |
| Sunchoke | — | — | Mar 20 | Jul 10 – Sep 4 | 110–150 |
| Sunflower | Jan 23 | Mar 6 | Mar 13 | May 22 – Jul 10 | 70–100 |
| Sweet Corn | — | Mar 13 | — | May 15 – Jun 26 | 60–90 |
| Sweet Potatoes | Jan 23 | Mar 6 | Mar 13 | Jun 12 – Jul 31 | 90–120 |
| Tatsoi | Feb 6 | Feb 13 | Mar 6 | Apr 10 – May 15 | 35–50 |
| Tomatillo | Jan 23 | Mar 6 | Mar 13 | May 15 – Jul 24 | 60–85 |
| Tomatoes | Jan 23 | Mar 6 | Mar 13 | May 15 – Jul 24 | 60–85 |
| Turmeric | Jan 23 | Mar 6 | Mar 13 | Nov 13 – Jan 8 | 240–300 |
| Turnip | — | Feb 13 | — | Mar 27 – May 1 | 40–60 |
| Watercress | Feb 6 | Feb 13 | Mar 6 | Apr 17 – May 22 | 40–60 |
| Watermelon | Feb 6 | Mar 6 | Mar 13 | May 22 – Jul 10 | 70–100 |
| Wax Beans | — | Mar 13 | — | May 8 – Jul 3 | 50–65 |
| Winter Melon | Jan 23 | Mar 6 | Mar 13 | Jun 12 – Jul 31 | 90–120 |
| Yam | Jan 23 | Mar 6 | Mar 13 | Sep 11 – Jan 8 | 180–330 |
| Yard Long Beans | Jan 23 | Mar 6 | Mar 13 | May 8 – Jun 19 | 55–80 |
| Zucchini | Feb 6 | Mar 6 | Mar 13 | May 1 – Jun 26 | 45–60 |
🍓 Fruits to Grow in Glenn County
24 fruits that grow well in Zone 9a with planting dates for Glenn County.
Show all 24 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Mar 20 | Jun 19 – Oct 2 | 90–180 |
| Blackberries | — | — | Mar 20 | — | 365–730 |
| Boysenberries | — | — | Mar 20 | — | 365–730 |
| Cantaloupe | — | — | Mar 20 | May 29 – Jul 3 | 70–90 |
| Che Fruit | — | — | Mar 20 | — | 1095–1825 |
| Dragon Fruit | — | — | Mar 20 | — | 365–730 |
| Elderberries | — | — | Mar 20 | — | 730–1095 |
| Figs | — | — | Mar 20 | — | 730–1825 |
| Goji Berries | — | — | Mar 20 | — | 730–1095 |
| Grapes | — | — | Mar 20 | — | 730–1095 |
| Ground Cherry | — | — | Mar 20 | May 29 – Jul 24 | 65–80 |
| Guava | — | — | Mar 20 | — | 365–730 |
| Honeydew | — | — | Mar 20 | Jun 12 – Jul 24 | 80–110 |
| Kiwi | — | — | Mar 20 | — | 1095–1825 |
| Loquat | — | — | Mar 20 | — | 730–1825 |
| Mulberries | — | — | Mar 20 | — | 730–1825 |
| Passion Fruit | — | — | Mar 20 | — | 365–545 |
| Pawpaw | — | — | Mar 20 | — | 1095–2555 |
| Persimmon | — | — | Mar 20 | — | 1095–2555 |
| Pomegranate | — | — | Mar 20 | — | 730–1095 |
| Quince | — | — | Mar 20 | — | 1095–1825 |
| Raspberries | — | — | Mar 20 | — | 365–730 |
| Serviceberries | — | — | Mar 20 | — | 730–1095 |
| Strawberries | — | — | Mar 20 | Jun 19 – Jan 15 | 90–365 |
🌿 Herbs to Grow in Glenn County
40 herbs that grow well in Zone 9a with planting dates for Glenn County.
Show all 40 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Anise | Feb 6 | Feb 13 | Feb 27 | May 29 – Aug 14 | 90–120 |
| Basil | Jan 23 | Mar 13 | Mar 13 | May 8 – Jul 10 | 50–75 |
| Bee Balm | — | — | Mar 13 | Jun 12 – Aug 28 | 90–120 |
| Borage | Feb 6 | Feb 13 | Feb 27 | Apr 24 – Jun 12 | 50–60 |
| Caraway | Feb 6 | Feb 13 | Feb 27 | — | 365–450 |
| Catnip | — | — | Mar 13 | May 15 – Jul 17 | 60–80 |
| Chamomile | Feb 6 | Feb 13 | Feb 27 | May 1 – Jul 10 | 60–90 |
| Chervil | Feb 6 | Feb 13 | Feb 27 | Apr 10 – Jun 12 | 40–60 |
| Chives | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Cilantro | Feb 6 | Feb 13 | Feb 27 | Apr 10 – Jun 12 | 40–60 |
| Comfrey | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Cumin | Feb 6 | Feb 13 | Feb 27 | Jun 12 – Aug 14 | 100–120 |
| Dill | Feb 6 | Feb 13 | Feb 27 | Apr 10 – Jun 12 | 40–60 |
| Echinacea | — | — | Mar 13 | Jul 17 – Oct 23 | 120–180 |
| Epazote | Jan 23 | Mar 13 | Mar 13 | May 1 – Jun 26 | 45–60 |
| Fennel (herb) | Feb 6 | Feb 13 | Feb 27 | May 1 – Jul 10 | 60–90 |
| Feverfew | — | — | Mar 13 | Jun 12 – Aug 28 | 90–120 |
| Garlic Chives | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Horehound | — | — | Mar 13 | May 29 – Jul 24 | 75–90 |
| Hyssop | — | — | Mar 13 | May 22 – Jul 24 | 70–90 |
| Lavender | — | — | Mar 13 | Jun 12 – Nov 13 | 90–200 |
| Lemon Balm | — | — | Mar 13 | May 15 – Jul 3 | 60–70 |
| Lemon Thyme | — | — | Mar 13 | May 22 – Jul 24 | 70–90 |
| Lemon Verbena | Jan 23 | Mar 13 | Mar 13 | May 15 – Jul 24 | 60–90 |
| Lemongrass | Jan 23 | Mar 13 | Mar 13 | May 29 – Aug 28 | 75–120 |
| Marjoram | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Mint | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Oregano | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Parsley | Feb 6 | Feb 13 | Feb 27 | May 1 – Jul 3 | 60–80 |
| Rosemary | — | — | Mar 13 | Jun 5 – Oct 23 | 80–180 |
| Rue | — | — | Mar 13 | May 22 – Jul 24 | 70–90 |
| Sage | — | — | Mar 13 | May 29 – Jul 24 | 75–90 |
| Savory | — | — | Mar 13 | May 8 – Jul 3 | 50–70 |
| Sorrel | Feb 6 | Feb 13 | Feb 27 | Apr 10 – Jun 12 | 40–60 |
| Stevia | Jan 23 | Mar 13 | Mar 13 | May 15 – Jul 24 | 60–90 |
| Tarragon | — | — | Mar 13 | May 15 – Jul 24 | 60–90 |
| Thai Basil | Jan 23 | Mar 13 | Mar 13 | May 8 – Jul 10 | 50–75 |
| Thyme | — | — | Mar 13 | May 22 – Jul 24 | 70–90 |
| Valerian | — | — | Mar 13 | Jul 17 – Oct 23 | 120–180 |
| Yarrow | — | — | Mar 13 | Jun 12 – Aug 28 | 90–120 |
Monthly Planting Guide for Glenn County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Glenn County.
Frequently Asked Questions
What planting zone is Glenn County, CA?
Glenn 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 Glenn County, CA?
Based on 31 years of NOAA weather station data, the median last spring frost in Glenn County falls around March 6. In 8 out of 10 years, last frost lands between January 14 and April 18 — a 95-day window of variability. Use April 18 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Glenn County, CA?
The median first fall frost in Glenn County arrives around November 28. In cold years it can arrive as early as November 8; 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 Glenn County?
Glenn County has a frost-free growing season of approximately 267 days. This long season supports multiple succession plantings and warm-season crops that need extended heat, like sweet potatoes and melons. Climate records show the growing season is trending longer by about 10.14 days per decade.
What is the soil like in Glenn County for gardening?
Glenn County has predominantly Loam soil with a pH range of 6.5–7.9 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Glenn County?
Glenn 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 Glenn County a good location for home gardening?
Glenn County scores 51/100 (Moderate) 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 Glenn 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.
