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

Location

Agate, North Dakota

ZIP Code

58310

USDA Zone

Last Frost

Wednesday, May 20, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Wednesday, March 11, 2026

Transplant Outdoors

Wednesday, June 3, 2026

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

Pro tip: Start Petunia seeds indoors 10 weeks before your last frost date, then transplant outdoors around Wednesday, June 3, 2026.

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🌿 Plant Details

Scientific Name Petunia × hybrida

Days to Maturity 75 days

Mature Height 6-18"

Spread 18"

Type Annual

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate (1 inch/week)

↔️

Spacing

12" apart

🌱

Planting Depth

0.13" deep

Seeds typically germinate in 7-14 days

Ready to Plant Petunia in Agate?

Get your seeds now so they're ready by Wednesday, March 11, 2026.

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🤝 Good Companions

TomatoBasilMarigold

⚠️ Avoid Planting Near

Fennel

🤝

Full Companion Planting Guide for Petunia

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

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🌍 Flower Garden Soil ✂️ Pruning Shears 🚿 Watering Can

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

🌾 Seed Saving Guide

🟡 Moderate

⚠️ Many varieties are F1 hybrid — look for OP/heirloom types

When to Harvest Seed

Allow seed pods to form after flowers fade. Harvest when the small pod turns tan and begins to split.

Processing

Collect tiny seeds in a bowl when pod splits, dry 1 week before storing.

Seed Viability

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

Pro Tip

Most petunias are F1 hybrids — seedlings will not match the parent. Look for OP/heirloom varieties for reliable seed.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 32 plants of Petunia. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

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

In Agate (Zone 3b), start Petunia seeds indoors around Wednesday, March 11, 2026 and transplant outdoors around Wednesday, June 3, 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 Petunia take to grow? +

Petunia typically matures in about 75 days from transplanting. In Agate, that means you can expect harvest around Wednesday, June 3, 2026 plus 75 days.

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

Petunia should be started indoors 10 weeks before your last frost date. In Agate, that means starting around Wednesday, March 11, 2026.

📚 More Petunia Planting Guides

🗺️

Petunia in North Dakota

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 3b Petunia Guide

All cities in your zone · Avg dates

→

Other Plants for Agate

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Growing Petunia in Zone 3b

Petunia (Petunia × hybrida) is a popular garden vegetable. In Agate, North Dakota, which is in USDA Hardiness Zone 3b, you should start seeds indoors around Wednesday, March 11, 2026.

Your average last frost date is Wednesday, May 20, 2026. Plan to transplant your Petunia seedlings outdoors around Wednesday, June 3, 2026, about 2 weeks after your last frost date.