When to Plant Shallot in San Juan County, CO
Your May gardening checklist
May is a pivotal month for San Juan County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.
A few tasks this May that'll pay off in June
- Transplants going out: shallot
- Direct-sowing: shallot
- Fall sowing: shallot
Shallots are a gourmet allium prized for their complex, sweet, and mild flavor. Each bulb multiplies into a cluster, making them easy and rewarding to grow.
San Juan County, Colorado 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 feet, San Juan County receives approximately 20.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Shallot to ensure they mature before fall.
San Juan County Soil Profile
Soil Type
Loam
Soil pH
6.3-8
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in San Juan County
How your county's soil matches Shallot's growing requirements.
Soil pH
Your soil pH (6.3–8.0) is more alkaline than Shallot prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in San Juan County is excellent for Shallot — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Shallot.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Shallot.
How to Plant Shallot
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Shallot
Shallot needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Shallot Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | — | 2.4" | 0" | ❄️ Dormant |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Aug | 4.3" | 2.3" | 2" | 💧 Light watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in San Juan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Shallot Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Shallot Planting Timeline — San Juan County, CO
Shallot Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 14 | May 14 – May 28 |
| Transplant Outdoors | June 18 | Jun 18 – Jul 2 |
| Direct Sow | June 4 | Jun 4 – Jun 25 |
| Harvest | September 17 | Sep 17 – Nov 5 |
| Fall Sowing | June 30 | Jun 30 – Jul 14 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Transplant Outdoors Fall Sowing |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
82 days in San Juan County
Growing Tips for Shallot in San Juan County
Direct sow Shallot outdoors after June 18 in San Juan County when soil has warmed and frost danger has passed.
Your 82.0-day growing season in San Juan County is tight for Shallot (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Shallot in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
San Juan County receives only 20" of rain annually. Shallot needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Plant sets in fall for spring harvest or early spring for summer harvest. Mulch heavily if overwintering. Harvest when tops brown and dry, then cure for storage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Shallot in Other Locations
Frequently Asked Questions
When should I plant Shallot in San Juan County, CO?
San Juan County is in Zone 5a with an average last frost of June 18. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Juan County, CO?
San Juan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 8.
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.