When to Plant Tomatoes in Yuma County, CO
May to-do list for Yuma County, Colorado
We've pulled the most time-sensitive tasks for Yuma County, Colorado this May and put them front and centre. Tackle them in order.
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Plant out tomatoes
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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Plant tomatoes from seed, right in the garden
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.
Yuma County, Colorado is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 5, giving you a growing season of approximately 147 days.
At an elevation of 7,664 feet, Yuma County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Tomatoes during the growing season.
Yuma County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.9
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 Yuma County
How your county's soil matches Tomatoes's growing requirements.
Soil pH
Your soil pH (6.6–7.9) is more alkaline than Tomatoes prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Yuma County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Tomatoes.
How to Plant Tomatoes
Succession Planting Tomatoes
Sow every 6.9 weeks. Last sowing by Jul 12 to harvest before frost.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tomatoes
Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.
| Month | Tomatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 5.2" | 2.3" | 2.9" | 🚿 Regular watering |
| Jun | 5.2" | 1.4" | 3.8" | 🚿 Regular watering |
| Jul | 5.2" | 1.9" | 3.3" | 🚿 Regular watering |
| Aug | 5.2" | 2.2" | 3" | 🚿 Regular watering |
| Sep | 5.2" | 1.9" | 3.3" | 🚿 Regular watering |
| Oct | 5.2" | 1.9" | 3.3" | 🚿 Regular watering |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Yuma County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tomatoes 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.
Tomatoes Planting Timeline — Yuma County, CO
Tomatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Direct Sow | May 18 | May 18 – Jun 8 |
| Harvest | July 27 | Jul 27 – Oct 5 |
Plant 0.5" deep · 24" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 2-3 times/week
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5b
📆 Growing Season
147 days in Yuma County
Growing Tips for Tomatoes in Yuma County
Direct sow Tomatoes outdoors after May 11 in Yuma County when soil has warmed and frost danger has passed.
Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
Yuma County receives only 20" of rain annually. Tomatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.
Recommended Tomatoes Varieties for Yuma County
Choose determinate, early-maturing varieties for your short season
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.
Tomatoes in Other Locations
Frequently Asked Questions
When should I plant Tomatoes in Yuma County, CO?
Yuma County is in Zone 5b with an average last frost of May 11. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yuma County, CO?
Yuma County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 5.
Your Yuma County Garden Planner — Free
A 24-page printable planner built for Yuma County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.