my LocalPlanting

When to Plant Lupine in Agate, North Dakota (58310)

Location

Agate, North Dakota

ZIP Code

58310

USDA Zone

3b

Last Frost

Wednesday, May 20, 2026

📅 Your 2026 Planting Dates

Direct Sow Outdoors

Wednesday, April 22, 2026

Based on last frost Wednesday, May 20, 2026 · Zone 3b

Pro tip: Sow Lupine directly outdoors 4 weeks before your last frost date.

🌿 Plant Details

Scientific Name Lupinus polyphyllus
Days to Maturity 365 days
Mature Height 24-48"
Spread 24"

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Moderate (1 inch/week)

↔️

Spacing

18" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 14-21 days

Ready to Plant Lupine in Agate?

Get your seeds now so they're ready by Wednesday, April 22, 2026.

* Affiliate links — we may earn a small commission at no extra cost to you.

🤝 Good Companions

CarrotBrassicasCorn

⚠️ Avoid Planting Near

Fennel
🤝

Full Companion Planting Guide for Lupine

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

🛠️ Supplies You'll Need

* Affiliate links — we may earn a small commission at no extra cost to you.

🌾 Seed Saving Guide

🟢 Easy
✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow seed pods to dry on the plant — pods will turn black and begin to twist when fully ripe.

Processing

Collect before pods explode and fling seeds. Shell pods, dry seeds 1 week.

Seed Viability

Up to 3 years when stored cool, dark, and dry.

Pro Tip

Lupine seeds have a hard coat — nick with sandpaper or soak 24 hours before sowing to improve germination.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 14 plants of Lupine. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Lupine in Agate, North Dakota? +

In Agate (Zone 3b), direct sow Lupine outdoors around Wednesday, April 22, 2026.

What is the last frost date for Agate, North Dakota? +

The average last spring frost date for Agate, North Dakota (ZIP 58310) is around Wednesday, May 20, 2026. This is based on NOAA climate normals for USDA Zone 3b.

How long does Lupine take to grow? +

Lupine typically matures in about 365 days from direct sowing. In Agate, that means you can expect harvest around Wednesday, April 22, 2026 plus 365 days.

Should I start Lupine indoors or direct sow in North Dakota? +

Lupine does best when direct sown outdoors. In Agate, sow directly around Wednesday, April 22, 2026.

Other Plants for Agate

Growing Lupine in Zone 3b

Lupine (Lupinus polyphyllus) is a popular garden vegetable. In Agate, North Dakota, which is in USDA Hardiness Zone 3b, you should direct sow seeds around Wednesday, April 22, 2026.

Your average last frost date is Wednesday, May 20, 2026. Lupine grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.