How to Grow Marshmallow
Marshmallow At a Glance
Difficulty
Easy
Category
Herb
Sun Exposure
Full Sun
Frost Tolerance
Frost Hardy
Cold Hardiness
Survives to -29°C
Plant Family
Malvaceae
Growing Season
Warm Season
Plant Lifecycle
Perennial
How to Start It
★ Recommended for beginners
Marshmallow seeds sprout best after a cold spell, so sow outdoors in late fall and let winter do the work. Or mix the seeds with damp sand in a bag, keep it in the fridge for 4 weeks, and sow in early spring, about 2 weeks before your last frost. Sow seeds 0.5 cm deep and cover them lightly. They sprout slowly, in 14 to 28 days: thin them (pull the extras so each has room) to 60 cm apart.
Marshmallow is a tall, soft-leaved plant that comes back every year, even through cold winters, with pale pink flowers that bees love. Its root was used to make the first marshmallow candy. It likes damp ground, so it is a great fit for a low, wet corner where other plants struggle.
When To Start
Marshmallow needs warmth. Wait until your last frost has passed and the soil has warmed before sowing.
We do not have exact sowing dates for this one yet.
When should you plant Marshmallow?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Marshmallow Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Marshmallow Calendar
Set your location to turn these into exact dates and reminders.
Sow chilled marshmallow seeds outdoors now
2 weeks before your last frost
Optional: start chilled marshmallow seeds indoors
8 weeks before your last frost· optional
Plant marshmallow seedlings out in a damp, sunny spot
Around your last frost· optional
Dig some marshmallow roots in the fall of year 2
1 week before your first frost· every year
Did you water your marshmallow seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
How is your marshmallow doing? Keep the soil damp while the young plants settle in.
About 30 days after you plant it
Your marshmallow has had time to settle in. Water during dry spells, it likes moist soil.
About 90 days after you plant it
The Journey Ahead
Marshmallow's Lifecycle
Seedling
Mature Plant
Seed Production
Step 1
Prepare Your Space
0.5 cm
Seeding Depth
60 cm
Plant Spacing
75 cm
Row Spacing
Vertical Growing
No.
Succession Planting
No.
Good Companions
Bad Companions
Step 2
Planting & Sprouting
Expect sprouts in 14–28 days
Growing Tips
- 1Grow marshmallow in full sun or light shade.
- 2It likes rich, damp soil, so mix in plenty of compost.
- 3Water often and never let the soil dry out for long, since it grows naturally in wet meadows and marshes.
- 4Spread compost or worm castings around the plants each spring.
- 5The stems can reach 1 to 2 m, so give it a spot at the back of a bed, or a stake in windy places.
- 6Wash aphids off with a spray of water, and pick off any leaves with orange rust spots.
Seedling Phase
Step 3
Growth & Maturity
150 cm
Mature Height
60 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
When to Pick
Leaves/flowers in summer; roots in autumn of year 2+
How to Harvest
- 1Pick young leaves and flowers through the summer to eat raw in salads or cooked like spinach.
- 2Wait 2 full seasons before digging roots, so they have time to grow thick.
- 3In the fall of the second year, once the leaves start to fade, dig up the plant and cut off some of the roots.
- 4Replant the crown with a few roots left on it so it keeps growing.
- 5Wash the roots, cut them into small pieces and dry them on a screen in a warm, airy spot until they snap.
Step 5
Saving Seeds
How to Save Seeds
Marshmallow grows true from seed. Once the flowers fade, they turn into flat, round seed heads shaped like little wheels. Pick them when they are brown and dry, and break them apart to free the seeds. Store the seeds labelled in a cool, dark, dry place, where they keep for a few years. Fresh seed sown outdoors in fall usually sprouts best in spring, after a winter in the cold.
Seed Production
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