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When to Plant Cress in Petersburg Borough, AK

Garden cress is one of the fastest-growing edibles, producing peppery sprouts in as little as two weeks. It is excellent for microgreens and garnishes.

Petersburg Borough, Alaska is in USDA Zone 7a. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.

At an elevation of 974 feet, Petersburg Borough receives approximately 17.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 57ยฐF, so choose short-season varieties of Cress to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cress successfully. Mulch heavily to conserve soil moisture.

Petersburg Borough, AK (Zone 7a) Moderate season
180 days
Last Spring Frost April 23
180 growing days
First Fall Frost October 20

Petersburg Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (141 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Apr 30 – May 21
Recommended (50%) ✓ Fits season (145 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 7 – May 28
Safe Start (90%) ✓ Fits season (146 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: May 26 – Jun 16

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 471 gal / 100 sq ft
Cress needs ~0 GDD — county provides 0 GDD May not mature

Cress Planting Timeline โ€” Petersburg Borough, AK

Cress Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 โ€“ Apr 2
Transplant Outdoors April 23 Apr 23 โ€“ May 7
Direct Sow April 9 Apr 9 โ€“ Apr 30
Fall Sowing August 11 Aug 11 โ€“ Aug 25
Harvest May 7 May 7 โ€“ May 28

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

14โ€“21 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

180 days

Growing Tips for Petersburg Borough

Sow seeds thickly on moist soil or paper towels. Keep moist and harvest when 2-3 inches tall. Succession sow every few days for continuous supply. Grows well indoors year-round.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Cress in Petersburg Borough, AK?

Petersburg Borough is in Zone 7a with an average last frost of April 23. Plan your Cress planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Petersburg Borough, AK?

Petersburg Borough, Alaska is in USDA Hardiness Zone 7a. The average last spring frost is April 23 and first fall frost is October 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Petersburg Borough gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 Petersburg Borough, AK. Local conditions may vary. Last updated: April 2026.