Growing Sunflowers | MU Extension

New

May 2021

Youth Gardening Activities series

This guide is one in a new series of youth gardening activities. See the related publications list for other guides in this series.

Donna Aufdenberg
Field Specialist in Horticulture

Sunflowers are an easy, fast-growing flower that can add much fun to the garden. They can be grown for flowers or for seed. Learn about common varieties and how to grow them in this one-page guide.

Common varieties

Large — Titan, Cyclops, Mammoth Russian, Mammoth Grey Striped, American Giant
Semi-dwarf and dwarf — Teddy Bear, Sunspot
Fall colors — Autumn Beauty, Crimson Queen, Evening Star, Ring of Fire
Cut flower — Sonja, Jade

Sunflowers in all shapes and sizes

American Giant sunflower.
American Giant.

Sunspot sunflower.
Sunspot.

Ring of Fire sunflower.
Ring of Fire.

Teddy bear sunflower.
Teddy bear.

Autumn Beauty sunflower.
Autumn Beauty.

Tips for growing

It takes 70 to 120 days until bloom, depending on variety of sunflower. To determine planting date, establish when you want blooms to occur. Then count back on
the calendar by those number of days.
Stagger planting times to extend continuous bloom. Can be planted every 2 to 3 weeks.
Plant seeds no deeper than 1 inch and no closer than 6 inches apart.
If you plant a variety that gets taller than 10 feet, stake or brace it.
When cutting flowers for bouquets, cut early in the morning before the heat of the day to avoid wilting.
Seedlings can be started indoors 4 to 6 weeks before last average frost date.

Site preparation

Establish seed planting dates. Planting should be after the last expected frost.
Select a location with more than 6 hours of sun and well drained soil.
Remove weeds; turn over the soil or till the soil with hand cultivator and trowel.
Add a handful of compost or potting mix to the soil; mix into the soil.

Planting the seed

Plant in rows; make a trench 1-inch deep.
Varieties 2 to 5 feet tall, plant 6 inches apart.
Varieties over 5 feet, plant 12 inches apart.
Giant varieties, plant 24 inches apart.
Plant seed; cover with 1 inch of soil.
Water sunflower seeds.
Seeds will germinate in about 7 to 10 days.
If too many seeds are planted, thinning may be required.

Plant care

Sunflowers can withstand dry weather however regular watering will create strong roots that prevent toppling windy conditions.
Fertilize every 2 to 3 weeks with compost or fertilizer; keep plants healthy.
Weed control by hoeing or mulching.
Control insects and diseases.