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When to plant Carrots in Ada County, ID

Spring Carrots in Ada County goes in April 9–April 30, once nighttime temps stop dipping near freezing. A second sowing from August 7 to August 21 extends the harvest into fall.

When to Plant Carrots in Ada County, ID

Carrots
Ada County, Idaho Zone 7a July

Your July planting checklist for Ada County, Idaho

Each item below is timed to Ada County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 23
Avg. first frost October 16
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
  1. Bring in the carrots

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong August, finish these tasks
  • Fall sowing: carrots

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Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

Ada County, Idaho is in USDA Zone 7a. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 4,372 feet, Ada County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Carrots during the growing season. With low rainfall, drip irrigation is essential for growing Carrots successfully. Mulch heavily to conserve soil moisture.

Ada County, ID (Zone 7a) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Ada County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Carrots Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Jul 22
Recommended (50%) ✓ Fits season (78 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Jul 30
Safe Start (90%) ✓ Fits season (76 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 19

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 Ada County

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Carrots prefers (6.0–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Carrots.

How to Plant Carrots

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

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

Succession Planting Carrots

3
successive plantings in your 176-day season

Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Aug 07.

Carrots 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 616 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Carrots

Carrots 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 Carrots Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 3.5" 2" 1.5" 💧 Light watering
May 3.5" 2.4" 1.1" 💧 Light watering
Jun 3.5" 1.4" 2.1" 🚿 Regular watering
Jul 3.5" 1.8" 1.7" 💧 Light watering
Aug 3.5" 2.4" 1.1" 💧 Light watering
Sep 3.5" 1.5" 2" 🚿 Regular watering
Oct 3.5" 1.8" 1.7" 💧 Light watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Carrots 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.

Carrots needs ~1,225 GDD — county provides 3,080 GDD Excellent fit

Carrots Planting Timeline — Ada County, ID

Carrots Planting Calendar

Activity When Date Range
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 11 Jun 11 – Jul 16
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

176 days in Ada County

Growing Tips for Carrots in Ada County

Direct sow Carrots outdoors after April 23 in Ada County when soil has warmed and frost danger has passed.

Common pests for Carrots in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Ada County, ID?

Ada County is in Zone 7a with an average last frost of April 23. Plan your Carrots planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ada County, ID?

Ada County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is April 23 and first fall frost is October 16.

When should I plant Carrots in Ada County, ID?

In Ada County, ID, plant Carrots after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Ada County, ID for Carrots?

Ada County sits in USDA Zone 7a. Carrots grows reliably in zones 3a through 10b, so it's a good fit here.

Can Carrots grow in Ada County's climate?

Yes — Carrots grows well in Ada County's temperate climate. Ada County averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.

🌱

Your Ada County Garden Planner — Free

A 22-page printable planner built for Ada 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.

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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 Ada County, ID. Local conditions may vary. Last updated: July 2026.

Sources & credits

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