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When to Plant Tomatoes in Haines Borough, AK

Haines Borough, Alaska Zone 5b May

Your May planting checklist for Haines Borough, Alaska

Your Haines Borough, Alaska garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 7
Avg. first frost September 29
Soil temp (4") 58°F
Watering High
Pest pressure Low
Daylight 16.6 hrs
  1. Time to transplant tomatoes

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Direct-sow tomatoes

    These tolerate cool soil, so you're not gambling by sowing now.

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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.

Haines Borough, Alaska is in USDA Zone 5b. The average last spring frost is May 7 and the first fall frost is September 29, giving you a growing season of approximately 145 days.

At an elevation of 1,921 feet, Haines Borough receives approximately 57.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 68°F, so choose short-season varieties of Tomatoes to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatoes root diseases.

Haines Borough, AK (Zone 5b) Short season
145 days
Last Spring Frost May 7
145 growing days
First Fall Frost September 29

Haines Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 3 Transplant: May 12 🍅 Harvest: Jul 14 – Sep 22
Recommended (50%) ✗ May not fit
Start indoors: Mar 12 Transplant: May 21 🍅 Harvest: Jul 23 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 11 🍅 Harvest: Aug 13 – Oct 22

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 Haines Borough

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

Soil pH

Your soil pH (4.9–6.4) is more acidic than Tomatoes prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Haines Borough is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Tomatoes.

Organic Matter

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

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

2
successive plantings in your 145-day season

Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.

Plant Water Budget

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

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 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 5.2" 2.7" 2.5" 💧 Light watering
Jun 5.2" 4" 1.2" 💧 Light watering
Jul 5.2" 8.1" 0" ✅ Rainfall sufficient
Aug 5.2" 8.5" 0" ✅ Rainfall sufficient
Sep 5.2" 10.6" 0" ✅ Rainfall sufficient
Oct 6.5" 0" ❄️ Dormant
Nov 4.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Haines Borough). 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 needs ~72 GDD — county provides 145 GDD Excellent fit

Tomatoes Planting Timeline — Haines Borough, AK

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 14 May 14 – Jun 4
Harvest July 23 Jul 23 – Oct 1

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

MonthActivities
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 · Natural rainfall sufficient

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

145 days in Haines Borough

Growing Tips for Tomatoes in Haines Borough

Direct sow Tomatoes outdoors after May 07 in Haines Borough 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.

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 Haines Borough

Choose determinate, early-maturing varieties for your short season

Early Girl (52d) Stupice (55d) Glacier (55d) Sub Arctic Plenty (45d)

Disease-resistant varieties for your humid climate

Mountain Merit (VF) Defiant (LB) Iron Lady (EB/LB/SF)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Haines Borough, AK?

Haines Borough is in Zone 5b with an average last frost of May 7. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haines Borough, AK?

Haines Borough, Alaska is in USDA Hardiness Zone 5b. The average last spring frost is May 7 and first fall frost is September 29.

🌱

Your Haines Borough Garden Planner — Free

A 24-page printable planner built for Haines Borough (Zone 5b). 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 Haines Borough, 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.