Sunflower

Basic Information

Seed Number

61

Seed Name

Sunflower

Variety

Mammoth Russian

Category

Flower

Plant Family

Asteraceae

Plant Type

Giant annual sunflower (Helianthus annuus)

Planting Method

Direct Sow

Seed Status

In Seed Bank

Created

2026-08-14 00:50:34

Updated

2026-08-19 15:35:29

Planting Information

Start Planting Date

May 6

Last Recommended Planting Date

Jun 30

Plantable Months

May, June

Indoor Start

Not recorded

Direct Sow

May 6 – Jun 30

Transplant

Not Recommended

Indoor Start Weeks Before Frost

Not Recommended

Transplant Weeks After Frost

Not Recommended

Germination Days

7–10 days

Harvest/Maturity

Not recorded

Succession Planting

Not recorded

Growing Conditions

Ideal Soil Temperature

60°F+

Planting Depth

1 in

Plant Spacing

24 in

Row Spacing

30-36 in

Thin-To Spacing

24 in

Sun Requirements

Full sun; 6-8+ hours/day

Water Needs

Water regularly during establishment and flowering; established plants tolerate some dry periods

Soil Preference

Well-drained soil; pH approximately 6.0-6.8; benefits from fertile soil for maximum size

Minimum Container Size

giants need ground/large pots

Plant Height

8-12 ft

Perennial/Biennial Status

Annual

Container Friendly

No

Trellis/Support Needed

No

Frost Tolerant

No

Heat Tolerant

Yes

Drought Tolerant

Yes

Pollinator Friendly

Yes

Medicinal

No

Garden Uses

Companion Planting

Storage

Seed Source/Brand

MSU Extension; Detroit frost dates; Almanac Detroit

Packet Year

Not recorded

Quantity Notes

Not recorded

Purchase Date

Not recorded

Expiration Year

Not recorded

Storage Box

Not recorded

Container

Not recorded

Envelope

Not recorded

Row

Not recorded

Slot

Not recorded

Storage Notes

Not recorded

Notes

Original Planting Method: Direct sow
Outdoor / Direct Sow / Transplant Window: May 10 – Jul 10
Days to Harvest / Bloom: 60–100 days to bloom
Container Friendly: Dwarf yes; giants need ground/large pots
Medicinal / Herbal Use: Seeds useful; pollinator support
Succession / Reusable Notes: Succession sow for blooms. Tall types need wind protection.
Zone 6B Notes: Direct sow after frost.
Companion Plants: Cucumbers, squash, pumpkins, melons, corn, pollinator flowers, clover
Avoid Planting Near / Watch Outs: Potatoes; may shade small crops
Sources: MSU Extension: https://www.canr.msu.edu/resources/garden_planning_calendar | Detroit frost dates: https://www.ufseeds.com/vegetable-planting-calendar-detroit-michigan.html | Almanac Detroit: https://www.almanac.com/gardening/planting-calendar/MI/Detroit

[[RESEARCH ENRICHMENT START]]
Zone 6B: Direct sow after the May 5 frost date once soil is at least about 60°F. Plant in a wind-protected location because mature plants can become extremely tall and top-heavy.
Germination: Direct sow approximately 1 inch deep. Germination generally occurs within 7-10 days under favorable conditions.
Harvest: For edible seed, allow the back of the flower head to turn yellow-brown and seeds to become plump and firm. Protect ripening heads from birds if seed harvest is desired.
Seed Saving: Mammoth Russian is an open-pollinated sunflower type, but sunflowers cross readily through insect pollination. Isolate from other Helianthus annuus varieties for true seed.
Special Care: Tall plants may need protection from strong wind. Deep watering encourages strong root development.
Research Source: University of Minnesota Extension — https://extension.umn.edu/gardening-minnesota/sunflowers — 7-10 day germination, 1-inch depth, giant sunflower spacing, soil pH and planting after frost
Research Source: University of Georgia Extension — https://fieldreport.caes.uga.edu/publications/C1121/growing-sunflowers-in-the-home-garden/ — 60°F minimum soil temperature, full sun and direct-seeding culture
Research Source: Burpee — https://www.burpee.com/sunflower-mammoth-prod000397.html — Mammoth-type giant height, large seed heads, edible striped seed and pollinator value
[[RESEARCH ENRICHMENT END]]