When to Plant Watercress in Iron County, UT
Watercress is a semi-aquatic plant with a peppery, tangy flavor rich in vitamins and minerals. It grows naturally along streams and can be cultivated in containers with standing water.
Iron County, Utah is in USDA Zone 6b. The average last spring frost is May 21 and the first fall frost is October 1, giving you a growing season of approximately 133 days.
At an elevation of 6,296 feet, Iron County receives approximately 20 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Watercress during the growing season.
Iron County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.8
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 Iron County
How your county's soil matches Watercress's growing requirements.
Soil pH
Your soil pH (6.4–7.8) overlaps with Watercress's range (6.5–7.5), though not a perfect match.
Soil Texture
The loam soil in Iron County is excellent for Watercress — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Watercress.
How to Plant Watercress
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Watercress
Sow every 4.6 weeks. Last sowing by Aug 02 to harvest before frost.
For a dedicated fall crop, sow by Jul 23.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Watercress
Watercress needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Watercress Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 6.5" | 2.6" | 3.9" | 🚿 Regular watering |
| Jun | 6.5" | 1.4" | 5.1" | 🚿 Regular watering |
| Jul | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Aug | 6.5" | 2.2" | 4.3" | 🚿 Regular watering |
| Sep | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Oct | 6.5" | 1.7" | 4.8" | 🚿 Regular watering |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Iron County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Watercress 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.
Watercress Planting Timeline — Iron County, UT
Watercress Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 16 | Apr 16 – Apr 30 |
| Transplant Outdoors | May 21 | May 21 – Jun 4 |
| Direct Sow | May 7 | May 7 – May 28 |
| Harvest | July 2 | Jul 2 – Aug 6 |
| Fall Sowing | July 23 | Jul 23 – Aug 6 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
133 days in Iron County
Growing Tips for Watercress in Iron County
Direct sow Watercress outdoors after May 21 in Iron County when soil has warmed and frost danger has passed.
Common pests for Watercress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Iron County receives only 20" of rain annually. Watercress needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Grow in containers with trays of water kept fresh. Provide partial shade and cool conditions. Harvest stems by cutting above water level. Replace water frequently to prevent stagnation.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Watercress in Other Locations
Frequently Asked Questions
When should I plant Watercress in Iron County, UT?
Iron County is in Zone 6b with an average last frost of May 21. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iron County, UT?
Iron County, Utah is in USDA Hardiness Zone 6b. The average last spring frost is May 21 and first fall frost is October 1.
Plan Your Garden with Confidence
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