Planting Guides

When to Plant Green Beans in Boise: Complete Guide + Best Varieties for Zone 6a

Last updated: October 30, 2025

Learn when to plant green beans in Boise with specific dates for Zone 6a. Compare 6 varieties & discover which grow best in Idaho's climate.

LLily Nakamura

October 30, 2025

Green bean plants growing successfully in Boise Idaho garden with mountains visible in background — — Image © PlantReference.org 2026

Quick Answer

Plant green beans in Boise after May 11 when soil reaches 60°F. Start Provider variety first, then succession plant every 2-3 weeks through July 15.

TL;DR

Plant green beans in Boise after May 11 (one week after last frost date of May 4). Start succession plantings every 2-3 weeks through July 15 for continuous harvest until October. Provider and Roma II are best for multiple successions, while Kentucky Wonder pole beans maximize production in small spaces. All varieties need soil temperatures above 60°F for reliable germination in Idaho's Zone 6a climate.

Frequently Asked Questions

When should I start green bean seeds indoors in Boise?

Don't start bean seeds indoors. Green beans Phaseolus vulgaris must be direct sown because their taproots break easily during transplanting, causing severe transplant shock. Even if transplant survival occurs, the root damage delays harvest by 2-3 weeks, negating any advantage from indoor starting. Wait for soil temperatures to reach 60°F (16°C) in mid-May and sow directly in the garden.

How many succession plantings can I do in Boise's Zone 6a season?

Boise's 158-day growing season allows for 4-5 succession plantings using fast-maturing varieties. Start Phaseolus vulgaris 'Provider' on May 11, then plant new rows every 2-3 weeks through July 15. The final planting will mature by early September, well before October 9 first frost. For pole beans like Phaseolus vulgaris 'Kentucky Wonder', one planting in mid-May provides harvest from July through September.

Do green beans need inoculant in Boise soil?

Yes, especially in new garden beds or amended clay soil. Bean inoculant contains Rhizobium bacteria that form nitrogen-fixing nodules on roots. Native Idaho clay often lacks sufficient populations of the correct bacteria strain. Apply powdered inoculant to dampened seeds just before planting. This ensures strong nodulation for natural nitrogen production, reducing fertilizer needs and improving plant health.

What's the best green bean variety for Boise's dry climate?

Phaseolus vulgaris 'Provider' performs most reliably in Boise conditions. Its 50-55 day maturity handles our temperature fluctuations well, and the compact bush habit conserves soil moisture better than spreading varieties. For maximum production in small spaces, Phaseolus vulgaris 'Kentucky Wonder' pole beans tolerate dry conditions once established and produce continuously. Avoid Phaseolus vulgaris 'Dragon Tongue' unless you can provide consistent irrigation.

Should I use shade cloth for green beans in Boise summers?

Usually not necessary for properly timed plantings. Beans planted in May mature by mid-July before extreme heat arrives. However, if growing Phaseolus vulgaris 'Kentucky Wonder' through August heat, 30% shade cloth prevents flower drop when temperatures exceed 90°F (32°C). Focus on consistent deep watering rather than shading for bush varieties with shorter seasons.

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Written By

Lily Nakamura

Lily is a Master Gardener and high-desert homesteader outside Boise. She and her husband moved to Idaho from the Bay Area and had to completely relearn gardening for a climate with alkaline soil, intense sun, hard freezes, and limited water. Lily now grows a large vegetable garden, maintains a small orchard of cold-hardy fruit trees, and raises cut flowers for the local farmers market. She writes about the specific challenges of intermountain gardening—short seasons, temperature swings, and the importance of soil amendment in high-pH soils. Lily is honest about the learning curve: high-desert gardening is humbling, and she thinks more gardening writers should admit when conditions are genuinely difficult.