San Juan County, CO — Planting Guide
May in San Juan County, Colorado — your action list
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in San Juan County, Colorado.
Before June arrives, get these ready
- Transplants going out: kale, lettuce, and angelica
- Direct-sowing: basil, carrots, and cucumber
- First harvests: microgreens
- Fall sowing: carrots, kale, and lettuce
San Juan County is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 8, giving you a growing season of approximately 82 days.
At an elevation of 7,539 ft, San Juan County receives approximately 20.1 in of rainfall annually. Summer highs average 82°F with winter lows around 9°F. The predominant soil type is Loam.
Based on 30 years of NOAA climate station data, the last frost date here varies by 35 days year to year — ranging from May 24 in warm years to June 29 in cold years. The growing season is trending longer by about 4.37 days per decade. San Juan County scores 33/100 (Challenging) on the Microclimate Index.
🌡️ Zone
5a (°F to °F min)
❄️ Last Frost
June 18
🍂 First Frost
September 8
📅 Growing Season
82 days
⛰️ Elevation
7,539 ft
🌧️ Annual Rainfall
20.1 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 | 1.4 in | 7 days | — | None |
| Feb | 1.2 in | 6 days | — | None |
| Mar | 1.6 in | 7 days | — | None |
| Apr | 2 in | 7 days | 2.3 in | High |
| May | 2.4 in | 8 days | 1.9 in | High |
| Jun | 1.6 in | 4 days | 2.7 in | High |
| Jul | 2 in | 6 days | 2.3 in | High |
| Aug | 2.3 in | 7 days | 2 in | High |
| Sep | 1.6 in | 5 days | 2.7 in | High |
| Oct | 1.6 in | 6 days | 2.7 in | High |
| Nov | 1.3 in | 5 days | — | None |
| Dec | 1.1 in | 7 days | — | None |
Annual total: 20.1 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.
San Juan County Soil Profile
Soil Type
Loam
Soil pH
6.3-8
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) | Jun 29 | Oct 2 | 95 days |
| Cautious | Jun 23 | Sep 16 | 85 days |
| Average year | Jun 18 | Sep 8 | 82 days |
| Optimistic | Jun 7 | Sep 2 | 87 days |
| Aggressive (risky) | May 24 | Aug 12 | 80 days |
Not very — frost dates can vary by ±35 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 4.4 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
San Juan County has challenging growing conditions. Season extension and careful variety selection are essential.
Local Gardening Help in San Juan 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 San Juan County's climate and soil.
County Extension Office
San Juan County Colorado State University Extension Extension Office
Phone: 970-491-6281
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 San Juan County
Finding local nurseries & garden centers in San Juan County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to San Juan 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 San Juan County CO" or "garden center San Juan 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 San Juan County CO" or check your extension office and local parks department. Facebook groups like "San Juan County Gardeners" or "Colorado 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.
Sunlight & Day Length
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
14.6 hours
Summer solstice daylight
Shortest Day
9.4 hours
Winter solstice daylight
Peak Sun Hours
10.4 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 | 9.7 hr | 5.2 hr | Short day |
| February | 10.6 hr | 6.2 hr | Short day |
| March | 11.7 hr | 7 hr | Short day |
| April | 13 hr | 7.6 hr | Neutral |
| May | 14 hr | 8.4 hr | Long day |
| June | 14.6 hr | 10.4 hr | Long day |
| July | 14.4 hr | 9.7 hr | Long day |
| August | 13.5 hr | 9.1 hr | Neutral |
| September | 12.2 hr | 8.4 hr | Neutral |
| October | 11 hr | 7.2 hr | Short day |
| November | 9.9 hr | 5.9 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 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 rarely reaches 60°F — use black plastic mulch to warm soil.
Best Month to Compost
Jul
Microbial activity peaks when soil is warm.
Active Composting
2 months
Short season — insulate pile or use indoor vermicomposting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | -8°F | 2°F | ❄️ Dormant | ~36 weeks |
| Feb | -5°F | 1°F | ❄️ Dormant | ~36 weeks |
| Mar | 3°F | 7°F | ❄️ Dormant | ~36 weeks |
| Apr | 18°F | 17°F | ❄️ Dormant | ~36 weeks |
| May | 32°F | 29°F | ❄️ Dormant | ~36 weeks |
| Jun | 44°F | 37°F | 🐢 Slow | ~24 weeks |
| Jul | 52°F | 45°F | ♻️ Active | ~14 weeks |
| Aug | 52°F | 48°F | ♻️ Active | ~14 weeks |
| Sep | 43°F | 42°F | 🐢 Slow | ~24 weeks |
| Oct | 29°F | 35°F | ❄️ Dormant | ~36 weeks |
| Nov | 14°F | 21°F | ❄️ Dormant | ~36 weeks |
| Dec | -1°F | 10°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in San Juan County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 5 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | May, Jun, Jul, Aug |
| Cabbage worms | Moderate | Jun, Jul, Aug |
| Colorado potato beetle | Low | Jun, Jul |
| Flea beetles | Low | May, Jun, Jul |
| Slugs | Low | May, Jun, Jul, Aug, Sep |
Organic pest management tips
- Maintain healthy soil with regular compost additions to build natural pest resistance
- Practice crop rotation annually to break pest cycles
- Encourage beneficial insects with flowering herbs like dill, fennel, and yarrow
Cover Crops for San Juan County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
Spring Cover Crops (2 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Jun 27 | Jul 14 | — | Rapid growth, attracts pollinators, suppresses weeds |
| White clover | May 20 | Jul 14 | ✓ 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 | Jul 6 | Aug 25 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Fall Cover Crops (5 options) — Plant after harvest to protect soil over winter
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Daikon radish | Jul 21 | May 28 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jun 21 | May 28 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Aug 2 | May 28 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | May 31 | Jun 4 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jun 17 | Jun 4 | — | Erosion control, weed suppression, good biomass |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 14 mph Summer: 11 mph
Fall: 12 mph Winter: 15 mph
Prevailing wind: W. Windy area — plant a windbreak hedge on the W side of your garden.
Windbreak Benefit
6.6/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
High
Hilly terrain with 1,614 ft of elevation range — cold air pools in low spots. Avoid planting frost-sensitive crops in valleys.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
10,017 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 1,750 gal tank.
Legal Status
Limited
Your state has quantity limits on rainwater collection — check local regulations before installing large systems.
Best Collection Months
Apr, May, Jul, Aug
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Feb, Nov, Dec
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 20.1 inches of rain per year
- A 1,000 sq ft roof can collect roughly 10,017 gallons annually
- Check CO state regulations — rainwater harvesting has quantity limits
- Stock up on stored water before your dry season (Feb, Nov, Dec)
- Use a first-flush diverter to keep roof debris out of your collection
Soil & Growing Conditions in San Juan County
Soil Type
Loam
Soil pH 6.3–8 · Excessively Drained drainage
Good candidate for raised beds to maximise drainage and extend the season.
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
82-day frost-free season
A short season means indoor starts are critical for warm-season crops. Prioritise cold-hardy, fast-maturing varieties and use row covers to extend autumn harvests.
Your Free Printable Garden Planner
Plan every bed, every planting, every harvest — in one place. This 24-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
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
Boost soil fertility and structure with rich, well-aged organic compost.
🥬 Vegetables to Grow in San Juan County
106 vegetables that grow well in Zone 5a with planting dates for San Juan County.
Show all 106 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | May 14 | Jun 25 | Jul 2 | Sep 24 – Oct 29 | 80–100 |
| Amaranth | Apr 23 | Jun 25 | Jul 2 | Oct 1 – Nov 19 | 90–120 |
| Arugula | May 14 | Jun 4 | Jun 18 | Jul 23 – Sep 24 | 30–50 |
| Asparagus | — | — | Jul 2 | — | 730–1095 |
| Beets | — | Jun 4 | — | Jul 30 – Aug 27 | 50–70 |
| Belgian Endive | May 14 | Jun 4 | Jun 18 | Oct 8 – Dec 3 | 110–150 |
| Bitter Melon | Apr 23 | Jun 25 | Jul 2 | Sep 3 – Oct 15 | 60–90 |
| Black Beans | — | Jun 25 | — | Sep 24 – Nov 12 | 90–120 |
| Bok Choy | May 14 | Jun 4 | Jun 18 | Jul 30 – Sep 3 | 40–60 |
| Broccoli | May 14 | Jun 4 | Jun 18 | Aug 20 – Oct 1 | 60–90 |
| Broccoli Rabe | May 14 | Jun 4 | Jun 18 | Jul 30 – Sep 3 | 40–60 |
| Brussels Sprouts | May 14 | Jun 4 | Jun 18 | Sep 17 – Nov 12 | 90–130 |
| Butternut Squash | May 14 | Jun 25 | Jul 2 | Oct 1 – Nov 5 | 85–110 |
| Cabbage | May 14 | Jun 4 | Jun 18 | Aug 20 – Oct 15 | 60–100 |
| Calabash | Apr 23 | Jun 25 | Jul 2 | Sep 24 – Nov 19 | 80–120 |
| Carrots | — | Jun 4 | — | Aug 6 – Sep 10 | 60–80 |
| Cauliflower | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 15 | 55–100 |
| Celeriac | May 14 | Jun 4 | Jun 18 | Oct 1 – Nov 5 | 100–120 |
| Celery | May 14 | Jun 4 | Jun 18 | Sep 10 – Nov 5 | 80–120 |
| Celtuce | May 14 | Jun 4 | Jun 18 | Aug 20 – Oct 1 | 60–90 |
| Chard | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 1 | 50–60 |
| Chickpeas | May 14 | Jun 4 | Jun 18 | Sep 10 – Oct 22 | 80–110 |
| Chicory | May 14 | Jun 4 | Jun 18 | Aug 20 – Oct 1 | 60–85 |
| Chinese Cabbage | May 14 | Jun 4 | Jun 18 | Aug 13 – Sep 10 | 50–70 |
| Christmas Lima Beans | Apr 23 | Jun 25 | Jul 2 | Sep 24 – Oct 29 | 80–100 |
| Collard Greens | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 15 | 55–75 |
| Corn | — | Jun 25 | — | Aug 27 – Oct 22 | 60–100 |
| Cowpeas | — | Jun 25 | — | Aug 27 – Oct 8 | 60–90 |
| Cress | May 14 | Jun 4 | Jun 18 | Jul 2 – Jul 23 | 14–21 |
| Crookneck Squash | May 14 | Jun 25 | Jul 2 | Aug 20 – Sep 17 | 45–60 |
| Crosne | — | Jun 4 | — | Nov 5 – Nov 19 | 150–200 |
| Cucumber | May 14 | Jun 25 | Jul 2 | Aug 27 – Oct 22 | 50–70 |
| Daikon | — | Jun 4 | — | Jul 30 – Aug 27 | 50–70 |
| Delicata Squash | May 14 | Jun 25 | Jul 2 | Sep 24 – Oct 29 | 80–100 |
| Edamame | — | Jun 25 | — | Sep 10 – Oct 22 | 75–100 |
| Eggplant | Apr 9 | Jun 25 | Jul 2 | Sep 10 – Nov 12 | 65–85 |
| Endive | May 14 | Jun 4 | Jun 18 | Aug 6 – Sep 10 | 45–65 |
| Escarole | May 14 | Jun 4 | Jun 18 | Aug 13 – Sep 10 | 50–70 |
| Fava Beans | May 14 | Jun 4 | Jun 18 | Sep 3 – Oct 15 | 75–100 |
| Fennel | Apr 23 | Jun 25 | Jul 2 | Sep 3 – Oct 15 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | Jun 25 | — | Aug 20 – Oct 15 | 50–65 |
| Horseradish | — | — | Jul 2 | Nov 5 – Dec 17 | 120–180 |
| Hot Peppers | Apr 9 | Jun 25 | Jul 2 | Sep 10 – Dec 17 | 70–120 |
| Hubbard Squash | May 14 | Jun 25 | Jul 2 | Oct 15 – Nov 19 | 100–120 |
| Kabocha | May 14 | Jun 25 | Jul 2 | Oct 1 – Oct 29 | 85–100 |
| Kai Lan | May 14 | Jun 4 | Jun 18 | Aug 6 – Sep 3 | 45–60 |
| Kale | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 8 | 50–70 |
| Kidney Beans | — | Jun 25 | — | Sep 24 – Oct 29 | 85–110 |
| Kohlrabi | May 14 | Jun 4 | Jun 18 | Aug 6 – Sep 10 | 45–65 |
| Komatsuna | May 14 | Jun 4 | Jun 18 | Jul 23 – Aug 27 | 35–50 |
| Leeks | May 14 | Jun 4 | Jun 18 | Sep 17 – Dec 3 | 90–150 |
| Lentils | May 14 | Jun 4 | Jun 18 | Sep 10 – Oct 22 | 80–110 |
| Lettuce | May 14 | Jun 4 | Jun 18 | Jul 23 – Oct 1 | 30–60 |
| Lima Beans | — | Jun 25 | — | Aug 27 – Oct 8 | 60–90 |
| Mache | May 14 | Jun 4 | Jun 18 | Jul 30 – Sep 3 | 40–60 |
| Melon | May 14 | Jun 25 | Jul 2 | Sep 10 – Oct 29 | 70–100 |
| Microgreens | May 14 | Jun 4 | Jun 18 | Jun 25 – Jul 23 | 7–21 |
| Mitsuba | May 14 | Jun 4 | Jun 11 | Aug 6 – Oct 1 | 50–70 |
| Mizuna | May 14 | Jun 4 | Jun 18 | Jul 23 – Aug 20 | 30–45 |
| Mustard Greens | May 14 | Jun 4 | Jun 18 | Jul 23 – Sep 24 | 30–50 |
| Napa Cabbage | May 14 | Jun 4 | Jun 18 | Aug 13 – Sep 17 | 55–75 |
| New Zealand Spinach | Apr 23 | Jun 25 | Jul 2 | Aug 27 – Sep 24 | 55–70 |
| Okra | Apr 23 | Jun 25 | Jul 2 | Aug 27 – Oct 22 | 50–65 |
| Onion | May 14 | Jun 4 | Jun 18 | Sep 17 – Nov 5 | 90–120 |
| Pac Choi | May 14 | Jun 4 | Jun 18 | Jul 30 – Aug 27 | 40–55 |
| Parsnip | — | Jun 4 | — | Sep 17 – Oct 29 | 100–130 |
| Patty Pan Squash | May 14 | Jun 25 | Jul 2 | Aug 20 – Sep 17 | 45–60 |
| Peas | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 8 | 55–70 |
| Peppers | Apr 9 | Jun 25 | Jul 2 | Sep 3 – Nov 12 | 60–90 |
| Pole Beans | Apr 23 | Jun 25 | Jul 2 | Aug 27 – Oct 22 | 55–70 |
| Potatoes | Apr 23 | Jun 25 | Jul 2 | Sep 10 – Nov 19 | 70–120 |
| Pumpkin | May 14 | Jun 25 | Jul 2 | Oct 1 – Nov 19 | 85–120 |
| Purslane | May 14 | Jun 4 | Jun 18 | Jul 30 – Sep 3 | 40–60 |
| Radicchio | May 14 | Jun 4 | Jun 18 | Aug 20 – Sep 24 | 60–80 |
| Radish | — | Jun 4 | — | Jul 2 – Jul 23 | 22–35 |
| Rhubarb | — | — | Jul 9 | — | 365–730 |
| Romanesco | May 14 | Jun 4 | Jun 18 | Sep 3 – Oct 15 | 75–100 |
| Rutabaga | — | Jun 4 | — | Aug 27 – Oct 1 | 80–100 |
| Salsify | — | Jun 4 | — | Sep 17 – Oct 29 | 100–130 |
| Savoy Cabbage | May 14 | Jun 4 | Jun 18 | Aug 27 – Oct 22 | 70–110 |
| Scallions | May 14 | Jun 4 | Jun 18 | Aug 13 – Sep 10 | 50–70 |
| Scarlet Runner Beans | Apr 23 | Jun 25 | Jul 2 | Sep 3 – Oct 8 | 60–80 |
| Shallot | May 14 | Jun 4 | Jun 18 | Sep 17 – Nov 5 | 90–120 |
| Shiso | Apr 30 | Jun 25 | Jul 2 | Aug 27 – Oct 22 | 50–70 |
| Snap Peas | Apr 23 | Jun 25 | Jul 2 | Aug 27 – Oct 22 | 55–70 |
| Snow Peas | May 14 | Jun 4 | Jun 18 | Aug 13 – Oct 8 | 50–65 |
| Soybeans | — | Jun 25 | — | Sep 17 – Nov 12 | 80–120 |
| Spaghetti Squash | May 14 | Jun 25 | Jul 2 | Oct 1 – Oct 29 | 85–100 |
| Spinach | May 14 | Jun 4 | Jun 18 | Jul 23 – Sep 24 | 35–50 |
| Squash (Summer) | May 14 | Jun 25 | Jul 2 | Aug 20 – Oct 22 | 45–65 |
| Squash (Winter) | May 14 | Jun 25 | Jul 2 | Sep 24 – Nov 19 | 80–120 |
| Sunchoke | — | — | Jul 2 | Oct 22 – Dec 17 | 110–150 |
| Sunflower | Apr 23 | Jun 25 | Jul 2 | Sep 10 – Oct 29 | 70–100 |
| Sweet Corn | — | Jun 25 | — | Aug 27 – Oct 8 | 60–90 |
| Sweet Potatoes | Apr 23 | Jun 25 | Jul 2 | Oct 1 – Nov 19 | 90–120 |
| Tatsoi | May 14 | Jun 4 | Jun 18 | Jul 23 – Aug 27 | 35–50 |
| Tomatillo | Apr 23 | Jun 25 | Jul 2 | Sep 3 – Nov 12 | 60–85 |
| Tomatoes | Apr 23 | Jun 25 | Jul 2 | Sep 3 – Nov 12 | 60–85 |
| Turnip | — | Jun 4 | — | Jul 16 – Aug 20 | 40–60 |
| Watercress | May 14 | Jun 4 | Jun 18 | Jul 30 – Sep 3 | 40–60 |
| Watermelon | May 14 | Jun 25 | Jul 2 | Sep 10 – Oct 29 | 70–100 |
| Wax Beans | — | Jun 25 | — | Aug 20 – Oct 15 | 50–65 |
| Winter Melon | Apr 23 | Jun 25 | Jul 2 | Oct 1 – Nov 19 | 90–120 |
| Yard Long Beans | Apr 23 | Jun 25 | Jul 2 | Aug 27 – Oct 8 | 55–80 |
| Zucchini | May 14 | Jun 25 | Jul 2 | Aug 20 – Oct 15 | 45–60 |
🍓 Fruits to Grow in San Juan County
27 fruits that grow well in Zone 5a with planting dates for San Juan County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Jul 9 | Oct 8 – Dec 24 | 90–180 |
| Aronia | — | — | Jul 9 | — | 730–1095 |
| Blackberries | — | — | Jul 9 | — | 365–730 |
| Blueberries | — | — | Jul 9 | — | 730–1095 |
| Boysenberries | — | — | Jul 9 | — | 365–730 |
| Cantaloupe | — | — | Jul 9 | Sep 17 – Oct 22 | 70–90 |
| Che Fruit | — | — | Jul 9 | — | 1095–1825 |
| Cranberries | — | — | Jul 9 | — | 730–1095 |
| Currants | — | — | Jul 9 | — | 730–1095 |
| Elderberries | — | — | Jul 9 | — | 730–1095 |
| Goji Berries | — | — | Jul 9 | — | 730–1095 |
| Gooseberries | — | — | Jul 9 | — | 730–1095 |
| Grapes | — | — | Jul 9 | — | 730–1095 |
| Ground Cherry | — | — | Jul 9 | Sep 17 – Nov 12 | 65–80 |
| Hardy Kiwi | — | — | Jul 9 | — | 1095–1825 |
| Haskaps | — | — | Jul 9 | — | 730–1095 |
| Honeydew | — | — | Jul 9 | Oct 1 – Nov 12 | 80–110 |
| Jostaberry | — | — | Jul 9 | — | 730–1095 |
| Lingonberries | — | — | Jul 9 | — | 730–1095 |
| Medlar | — | — | Jul 9 | — | 1095–1825 |
| Mulberries | — | — | Jul 9 | — | 730–1825 |
| Pawpaw | — | — | Jul 9 | — | 1095–2555 |
| Persimmon | — | — | Jul 9 | — | 1095–2555 |
| Quince | — | — | Jul 9 | — | 1095–1825 |
| Raspberries | — | — | Jul 9 | — | 365–730 |
| Serviceberries | — | — | Jul 9 | — | 730–1095 |
| Strawberries | — | — | Jul 9 | Oct 8 – Dec 24 | 90–365 |
🌿 Herbs to Grow in San Juan County
37 herbs that grow well in Zone 5a with planting dates for San Juan County.
Show all 37 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | May 14 | Jun 4 | Jun 11 | — | 365–730 |
| Anise | May 14 | Jun 4 | Jun 11 | Sep 10 – Nov 26 | 90–120 |
| Basil | Apr 30 | Jun 25 | Jul 2 | Aug 27 – Oct 29 | 50–75 |
| Bee Balm | — | — | Jun 25 | Sep 24 – Dec 10 | 90–120 |
| Borage | May 14 | Jun 4 | Jun 11 | Aug 6 – Sep 24 | 50–60 |
| Caraway | May 14 | Jun 4 | Jun 11 | — | 365–450 |
| Catnip | — | — | Jun 25 | Aug 27 – Oct 29 | 60–80 |
| Chamomile | May 14 | Jun 4 | Jun 11 | Aug 13 – Oct 22 | 60–90 |
| Chervil | May 14 | Jun 4 | Jun 11 | Jul 23 – Sep 24 | 40–60 |
| Chives | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Cilantro | May 14 | Jun 4 | Jun 11 | Jul 23 – Sep 24 | 40–60 |
| Comfrey | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Cumin | May 14 | Jun 4 | Jun 11 | Sep 24 – Nov 26 | 100–120 |
| Dill | May 14 | Jun 4 | Jun 11 | Jul 23 – Sep 24 | 40–60 |
| Echinacea | — | — | Jun 25 | Oct 29 – Dec 10 | 120–180 |
| Epazote | Apr 30 | Jun 25 | Jul 2 | Aug 20 – Oct 15 | 45–60 |
| Fennel (herb) | May 14 | Jun 4 | Jun 11 | Aug 13 – Oct 22 | 60–90 |
| Feverfew | — | — | Jun 25 | Sep 24 – Dec 10 | 90–120 |
| Garlic Chives | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Horehound | — | — | Jun 25 | Sep 10 – Nov 5 | 75–90 |
| Hyssop | — | — | Jun 25 | Sep 3 – Nov 5 | 70–90 |
| Lavender | — | — | Jun 25 | Sep 24 – Dec 10 | 90–200 |
| Lemon Balm | — | — | Jun 25 | Aug 27 – Oct 15 | 60–70 |
| Lemon Thyme | — | — | Jun 25 | Sep 3 – Nov 5 | 70–90 |
| Lovage | — | — | Jun 25 | Sep 3 – Nov 5 | 70–90 |
| Mint | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Oregano | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Parsley | May 14 | Jun 4 | Jun 11 | Aug 13 – Oct 15 | 60–80 |
| Rue | — | — | Jun 25 | Sep 3 – Nov 5 | 70–90 |
| Sage | — | — | Jun 25 | Sep 10 – Nov 5 | 75–90 |
| Savory | — | — | Jun 25 | Aug 20 – Oct 15 | 50–70 |
| Sorrel | May 14 | Jun 4 | Jun 11 | Jul 23 – Sep 24 | 40–60 |
| Tarragon | — | — | Jun 25 | Aug 27 – Nov 5 | 60–90 |
| Thai Basil | Apr 30 | Jun 25 | Jul 2 | Aug 27 – Oct 29 | 50–75 |
| Thyme | — | — | Jun 25 | Sep 3 – Nov 5 | 70–90 |
| Valerian | — | — | Jun 25 | Oct 29 – Dec 10 | 120–180 |
| Yarrow | — | — | Jun 25 | Sep 24 – Dec 10 | 90–120 |
Monthly Planting Guide for San Juan County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in San Juan County.
Frequently Asked Questions
What planting zone is San Juan County, CO?
San Juan County is in USDA Hardiness Zone 5a. 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 San Juan County, CO?
Based on 30 years of NOAA weather station data, the median last spring frost in San Juan County falls around June 18. In 8 out of 10 years, last frost lands between May 24 and June 29 — a 35-day window of variability. Use June 29 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in San Juan County, CO?
The median first fall frost in San Juan County arrives around September 8. In cold years it can arrive as early as August 12; in mild years as late as October 2. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in San Juan County?
San Juan County has a frost-free growing season of approximately 82 days. Focus on short-season varieties and start warm-season crops indoors 6–8 weeks before last frost. Climate records show the growing season is trending longer by about 4.37 days per decade.
What is the soil like in San Juan County for gardening?
San Juan County has predominantly Loam soil with a pH range of 6.3–8 and Excessively Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in San Juan County?
San Juan County has commercial agriculture that includes Hay, Cattle, Wheat. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is San Juan County a good location for home gardening?
San Juan County scores 33/100 (Challenging) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Gardening here benefits from close attention to frost timing and season extension due to the challenging microclimate factors.
Your San Juan County Garden Planner — Free
A 24-page printable planner built for San Juan County (Zone 5a). 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