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When to plant Cress in Summit County, CO

For Cress in Summit County, the safe spring window opens around June 2 and closes around June 23. Last expected frost is June 16, first fall frost September 4, giving a 80-day growing season. A second sowing from June 26 to July 10 extends the harvest into fall.

When to Plant Cress in Summit County, CO

Summit County, Colorado Zone 5a June

Your June game plan for Summit County, Colorado

A quick June briefing for Summit County, Colorado gardeners — what's urgent, what's next, and what can wait.

Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 45°F
Watering High
Pest pressure High
Daylight 14.8 hrs
  1. Get cress in the ground

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Outdoor sowing time: cress

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

  3. Pick cress

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

  4. Start your fall crops: cress

    A row cover ready in the garage extends your harvest by weeks once the nights turn cold.

A few tasks this June that'll pay off in July
  • Starting indoors: cress
  • First harvests: cress

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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.

Summit County, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, 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.

Summit County, CO (Zone 5a) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4

Summit County Soil Profile

Soil Type

Loam

Soil pH

6.8-8

Drainage

Well Drained

Cress Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Jun 24 – Jul 15
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jun 30 – Jul 21
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: May 22 Transplant: Jun 26 🍅 Harvest: Jul 10 – Jul 31

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 Summit County

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

Soil pH

Your soil pH (6.8–8.0) is more alkaline than Cress prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Summit County is excellent for Cress — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Cress.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Cress.

How to Plant Cress

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Cress

7
successive plantings in your 80-day season

Sow every 1.6 weeks. Last sowing by Aug 14 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Cress Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 326 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Cress

Cress needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Cress Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 1.8" 0" ❄️ Dormant
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Summit County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cress 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.

Cress needs ~188 GDD — county provides 860 GDD Excellent fit

Cress Planting Timeline — Summit County, CO

Cress Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest June 30 Jun 30 – Jul 21
Fall Sowing June 26 Jun 26 – Jul 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

14–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

80 days in Summit County

Growing Tips for Cress in Summit County

Direct sow Cress outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.

Your generous 80.0-day season in Summit County allows multiple plantings of Cress. Sow every 7.0 days for continuous harvest.

Common pests for Cress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Summit County receives only 18" of rain annually. Cress needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cress in Summit County, CO?

Summit County is in Zone 5a with an average last frost of June 16. Plan your Cress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Summit County, CO?

Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.

When should I plant Cress in Summit County, CO?

In Summit County, CO, plant Cress after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.

What growing zone is Summit County, CO for Cress?

Summit County sits in USDA Zone 5a. Cress grows reliably in zones 2a through 11b, so it's a good fit here.

Can Cress grow in Summit County's climate?

Yes — Cress grows well in Summit County's temperate climate. Summit County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.

🌱

Your Summit County Garden Planner — Free

A 22-page printable planner built for Summit County (Zone 5a). 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 Summit County, CO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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