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When to Plant Watercress in Dillingham Census Area, AK

Dillingham Census Area, Alaska Zone 4b May

Your May planting checklist for Dillingham Census Area, Alaska

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Soil temp (4") 48°F
Watering High
Pest pressure Low
Daylight 16.8 hrs

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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.

Dillingham Census Area, Alaska is in USDA Zone 4b. The average last spring frost is May 1 and the first fall frost is September 6, giving you a growing season of approximately 128 days.

At an elevation of 410 feet, Dillingham Census Area receives approximately 54 inches of rainfall annually with predominantly silt loam soil. Summer highs average 60°F, so choose short-season varieties of Watercress to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

Dillingham Census Area, AK (Zone 4b) Short season
128 days
Last Spring Frost May 1
128 growing days
First Fall Frost September 6
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Dillingham Census Area Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: May 27 – Jul 1
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: May 27 – Jul 1
Safe Start (90%) ✓ Fits season (106 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: May 27 – Jul 1

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 Dillingham Census Area

How your county's soil matches Watercress's growing requirements.

Soil pH

Your soil pH (5.0–6.2) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Dillingham Census Area is excellent for Watercress — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Watercress.

Organic Matter

Organic matter is excellent (6.6%) — Watercress will thrive.

How to Plant Watercress

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 2.6" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 6.5" 2.3" 4.2" 🚿 Regular watering
Jun 6.5" 3.5" 3" 💧 Light watering
Jul 6.5" 7.3" 0" ✅ Rainfall sufficient
Aug 6.5" 8.4" 0" ✅ Rainfall sufficient
Sep 6.5" 9.5" 0" ✅ Rainfall sufficient
Oct 6.5" 0" ❄️ Dormant
Nov 4.2" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Dillingham Census Area). 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 needs ~0 GDD — county provides 0 GDD May not mature

Watercress Planting Timeline — Dillingham Census Area, AK

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Harvest June 12 Jun 12 – Jul 17
Fall Sowing June 14 Jun 14 – Jun 28

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June Fall Sowing Harvest
July Harvest
August
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

128 days in Dillingham Census Area

Growing Tips for Watercress in Dillingham Census Area

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 →

Frequently Asked Questions

When should I plant Watercress in Dillingham Census Area, AK?

Dillingham Census Area is in Zone 4b with an average last frost of May 1. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dillingham Census Area, AK?

Dillingham Census Area, Alaska is in USDA Hardiness Zone 4b. The average last spring frost is May 1 and first fall frost is September 6.

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Your Dillingham Census Area Garden Planner — Free

A 24-page printable planner built for Dillingham Census Area (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Dillingham Census Area, AK. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.