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When to Plant Lupine in Bay City, Michigan (48708)

Location

Bay City, Michigan

ZIP Code

48708

USDA Zone

6a

Last Frost

Monday, April 20, 2026

📅 Your 2026 Planting Dates

Direct Sow Outdoors

Monday, March 23, 2026

Based on last frost Monday, April 20, 2026 · Zone 6a

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 Bay City?

Get your seeds now so they're ready by Monday, March 23, 2026.

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🤝 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

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🌾 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 Bay City, Michigan? +

In Bay City (Zone 6a), direct sow Lupine outdoors around Monday, March 23, 2026.

What is the last frost date for Bay City, Michigan? +

The average last spring frost date for Bay City, Michigan (ZIP 48708) is around Monday, April 20, 2026. This is based on NOAA climate normals for USDA Zone 6a.

How long does Lupine take to grow? +

Lupine typically matures in about 365 days from direct sowing. In Bay City, that means you can expect harvest around Monday, March 23, 2026 plus 365 days.

Should I start Lupine indoors or direct sow in Michigan? +

Lupine does best when direct sown outdoors. In Bay City, sow directly around Monday, March 23, 2026.

Other Plants for Bay City

Growing Lupine in Zone 6a

Lupine (Lupinus polyphyllus) is a popular garden vegetable. In Bay City, Michigan, which is in USDA Hardiness Zone 6a, you should direct sow seeds around Monday, March 23, 2026.

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