When to Plant Watercress in Ottawa County, OK
What to do in May
Welcome to May in Zone 7a. These are the moves that will have the biggest impact on your growing season.
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Sow watercress in trays indoors
You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.
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Start harvesting watercress
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Get ahead of June
- First harvests: watercress
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.
Ottawa County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 26, giving you a growing season of approximately 200 days.
At an elevation of 716 feet, Ottawa County receives approximately 29.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Watercress during the growing season.
Ottawa County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.8
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 Ottawa County
How your county's soil matches Watercress's growing requirements.
Soil pH
Your soil pH (6.8–7.8) overlaps with Watercress's range (6.5–7.5), though not a perfect match.
Soil Texture
The loam soil in Ottawa County is excellent for Watercress — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Watercress will thrive.
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 27 to harvest before frost.
For a dedicated fall crop, sow by Aug 17.
Plant Water Budget
Water stress score is 6/10 — 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 | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 6.5" | 2.9" | 3.6" | 🚿 Regular watering |
| May | 6.5" | 4.6" | 1.9" | 💧 Light watering |
| Jun | 6.5" | 4.7" | 1.8" | 💧 Light watering |
| Jul | 6.5" | 3.5" | 3" | 💧 Light watering |
| Aug | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Sep | 6.5" | 2.8" | 3.7" | 🚿 Regular watering |
| Oct | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Ottawa 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 — Ottawa County, OK
Watercress Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 5 | Mar 5 – Mar 19 |
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
| Direct Sow | March 26 | Mar 26 – Apr 16 |
| Harvest | May 21 | May 21 – Jun 25 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | — |
| August | Fall Sowing |
| 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 7a
📆 Growing Season
200 days in Ottawa County
Growing Tips for Watercress in Ottawa County
Direct sow Watercress outdoors after April 09 in Ottawa County when soil has warmed and frost danger has passed.
Your generous 200.0-day season in Ottawa County allows multiple plantings of Watercress. Sow every 20.0 days for continuous harvest.
Common pests for Watercress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
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 Ottawa County, OK?
Ottawa County is in Zone 7a with an average last frost of April 9. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ottawa County, OK?
Ottawa County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 26.
Your Ottawa County Garden Planner — Free
A 24-page printable planner built for Ottawa County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.