When to Plant Kohlrabi in Caldwell, Idaho (83607)

Location

Caldwell, Idaho

ZIP Code

83607

USDA Zone

Last Frost

Friday, April 10, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Friday, March 13, 2026

Transplant Outdoors

Friday, March 27, 2026

Based on last frost Friday, April 10, 2026 · Zone 7a

Pro tip: Start Kohlrabi seeds indoors 4 weeks before your last frost date, then transplant outdoors around Friday, March 27, 2026.

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🌿 Plant Details

Scientific Name Brassica oleracea var. gongylodes

Days to Maturity 55 days

Mature Height 12-18"

Spread 8"

Type Bulb

Fruit Size Small-Medium (2-3 inch bulb)

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Regular (consistent moisture prevents cracking)

↔️

Spacing

6" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 4-7 days

Ready to Plant Kohlrabi in Caldwell?

Get your seeds now so they're ready by Friday, March 13, 2026.

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🤝 Good Companions

BeetOnionCucumberHerb

⚠️ Avoid Planting Near

TomatoPepperStrawberry

🤝

Full Companion Planting Guide for Kohlrabi

See which plants help Kohlrabi thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🪵 Raised Garden Bed 🌍 Vegetable Garden Soil 🛠️ Hand Trowel Set 🚿 Watering Can

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🌾 Seed Saving Guide

🔴 Difficult

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow plants to bolt in year 2. Harvest seed pods just before they shatter.

Processing

Thresh dried seed stalks in a bag, separate seeds from chaff by winnowing.

Seed Viability

Up to 4 years when stored cool, dark, and dry.

Pro Tip

Brassica oleracea — crosses with broccoli, cabbage, kale, and Brussels sprouts. Isolate by 1000 feet for purity.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 4 per sq ft of Kohlrabi. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Kohlrabi in Caldwell, Idaho? +

In Caldwell (Zone 7a), start Kohlrabi seeds indoors around Friday, March 13, 2026 and transplant outdoors around Friday, March 27, 2026.

What is the last frost date for Caldwell, Idaho? +

The average last spring frost date for Caldwell, Idaho (ZIP 83607) is around Friday, April 10, 2026. This is based on NOAA climate normals for USDA Zone 7a.

How long does Kohlrabi take to grow? +

Kohlrabi typically matures in about 55 days from transplanting. In Caldwell, that means you can expect harvest around Friday, March 27, 2026 plus 55 days.

Should I start Kohlrabi indoors or direct sow in Idaho? +

Kohlrabi should be started indoors 4 weeks before your last frost date. In Caldwell, that means starting around Friday, March 13, 2026.

📚 More Kohlrabi Planting Guides

🗺️

Kohlrabi in Idaho

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 7a Kohlrabi Guide

All cities in your zone · Avg dates

→

Other Plants for Caldwell

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Growing Kohlrabi in Zone 7a

Kohlrabi (Brassica oleracea var. gongylodes) is a popular garden vegetable. In Caldwell, Idaho, which is in USDA Hardiness Zone 7a, you should start seeds indoors around Friday, March 13, 2026.

Your average last frost date is Friday, April 10, 2026. Plan to transplant your Kohlrabi seedlings outdoors around Friday, March 27, 2026, about -2 weeks after your last frost date.