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When to Plant Chard in Gem County, ID

Gem County, Idaho Zone 7a May

Your May game plan for Gem County, Idaho

May is a pivotal month for Gem County, Idaho gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 9
Avg. first frost October 1
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Get chard in the ground

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

Before June arrives, get these ready
  • Starting indoors: chard

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Swiss chard is a colorful, heat-tolerant green with large crinkled leaves and vibrant stalks in red, yellow, and white. Both the leaves and stems are edible and nutritious.

Gem County, Idaho is in USDA Zone 7a. The average last spring frost is May 9 and the first fall frost is October 1, giving you a growing season of approximately 145 days.

At an elevation of 6,100 feet, Gem County receives approximately 16 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Chard during the growing season. With low rainfall, drip irrigation is essential for growing Chard successfully. Mulch heavily to conserve soil moisture.

Gem County, ID (Zone 7a) Short season
145 days
Last Spring Frost May 9
145 growing days
First Fall Frost October 1

Gem County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jun 26 – Aug 14
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 22
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: May 3 Transplant: Jun 7 🍅 Harvest: Aug 2 – Sep 20

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 Gem County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Chard prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Chard.

How to Plant Chard

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Chard

3
successive plantings in your 145-day season

Sow every 5.7 weeks. Last sowing by Aug 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 23.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.5″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 521 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Chard

Chard needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Chard Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 3.5" 1.7" 1.8" 🚿 Regular watering
Jun 3.5" 1.2" 2.3" 🚿 Regular watering
Jul 3.5" 1.5" 2" 🚿 Regular watering
Aug 3.5" 1.5" 2" 🚿 Regular watering
Sep 3.5" 1.4" 2.1" 🚿 Regular watering
Oct 3.5" 1.5" 2" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Chard 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.

Chard needs ~839 GDD — county provides 2,211 GDD Excellent fit

Chard Planting Timeline — Gem County, ID

Chard Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 9 May 9 – May 23
Direct Sow April 25 Apr 25 – May 16
Harvest July 4 Jul 4 – Aug 22
Fall Sowing July 23 Jul 23 – Aug 6

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

145 days in Gem County

Growing Tips for Chard in Gem County

Direct sow Chard outdoors after May 09 in Gem County when soil has warmed and frost danger has passed.

General growing tips

Direct sow or transplant after last frost. Harvest outer leaves regularly to encourage continuous production. Chard tolerates both heat and light frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Corn
  • Cucumbers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chard in Gem County, ID?

Gem County is in Zone 7a with an average last frost of May 9. Plan your Chard planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gem County, ID?

Gem County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 9 and first fall frost is October 1.

🌱

Your Gem County Garden Planner — Free

A 24-page printable planner built for Gem 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Gem County, ID. 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.