in , ,

When to Seed Start Annual Flowers

Sharing is caring!

Most annual flowers are frost-tender. Annual seeds should be sown outdoors after the last average frost date in spring. To get a head start on the season, seeds can be started indoors, and young plants can be set in the garden after the last frost.

Young plants of annuals started indoors should be hardened off before being transplanted into the garden. Harden off plants by exposing them to outdoor temperatures and sunlight for an hour or two each day for several days before transplanting.

Check the weather service or the cooperative extension near you for the average last frost date in spring where you live. Here’s when to start annual seeds indoors and when to set young transplants into the garden.

Good Products for Seed Starting Success at Amazon:

When to seed start and transplant annuals

Here are annuals you can seed start indoors before the last frost in spring. Click on the flower name in the left column to learn how to plant and grow these colorful annuals:

FlowerStart Seeds Indoors –weeks before the last frostTransplant into the garden
Ageratum6-8 weeksOn last frost date
Alyssum6-8 weeks1-2 weeks after last frost
Amaranth6-8 weeksAfter last frost
Bachelor’s Button6-8 weeksOn last frost date
Calendula6-8 weeks1-2 weeks after last frost
Celosia6-8 weeksOn last frost date
Coleus8-10 weeks1-2 weeks after last frost
Cosmos6-8 weeksOn last frost date
Delphinium6-8 weeks1-2 weeks after last frost
Gomphrena6-8 weeksOn last frost date
Marigold6-8 weeksOn last frost date
Morning Glory3-4 weeksAfter last frost
Nicotiana6-8 weeksOn last frost date
Pansy8-10 weeksOn last frost date
Petunia8-10 weeksOn last frost date
Pholox8-10 weeksOn last frost date
Portulaca6-8 weeksOn last frost date
Salvia6-8 weeksOn last frost date
Scabiosa6-8 weeksOn last frost date
Snapdragon8-10 weeksOn last frost date
Statice6-8 weeksOn last frost date
Stock8-10 weeksOn last frost date
Strawflower6-8 weeksOn last frost date
Sunflower3-4 weeks1-2 weeks after last frost
Verbena8-10 weeksOn last frost date
Zinnia4-6 week1-2 weeks after last frost

Also of interest:

Starting Plants from Seeds

When to Seed Start Annual Flowers

24 Annual Flowers to Plant in Summer

Tender Annual Flowers

How to Care for Annual Flowers

Growing Annual Flowers for Summer Bloom

Designing With Annual Flowers

Easiest Annual and Perennial Flowers to Start From Seed

16 Drought Tolerant Annuals

Planting a Container

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

How To Grow Tips

How To Grow Tomatoes

How To Grow Peppers

How To Grow Broccoli

How To Grow Carrots

How To Grow Beans

How To Grow Corn

How To Grow Peas

How To Grow Lettuce

How To Grow Cucumbers

How To Grow Zucchini and Summer Squash

How To Grow Onions

How To Grow Potatoes

How to Grow Swiss Cheese Plant — Monstera

How to Grow African Violet – Saintpaulia