Corn

Basic Information

Seed Number

108

Seed Name

Corn

Variety

Glass gem

Category

Vegetable

Plant Family

Poaceae

Plant Type

Flint/popcorn corn (Zea mays)

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 19

Last Recommended Planting Date

Jun 10

Plantable Months

May, June

Indoor Start

Not recorded

Direct Sow

May 19 – Jun 10

Transplant

Not Recommended

Indoor Start Weeks Before Frost

Not Recommended

Transplant Weeks After Frost

Not Recommended

Germination Days

7–14 days

Harvest/Maturity

110–120 days to fully dry mature ears

Succession Planting

Not recorded

Growing Conditions

Ideal Soil Temperature

60-85°F

Planting Depth

1-2 in

Plant Spacing

8-12 in

Row Spacing

24-36 in

Thin-To Spacing

8-12 in

Sun Requirements

Full sun

Water Needs

1-1.5 in/week; consistent moisture is especially important during tasseling, silking and kernel fill

Soil Preference

Fertile, well-drained soil with adequate nitrogen and organic matter; approximately pH 5.8-7.0

Minimum Container Size

Not recorded

Plant Height

Typically about 6 ft; can reach 9 ft

Perennial/Biennial Status

Annual

Container Friendly

No

Trellis/Support Needed

No

Frost Tolerant

No

Heat Tolerant

Yes

Drought Tolerant

No

Pollinator Friendly

No

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 15 – Jun 25
Days to Harvest / Bloom: 70–110 days
Pollinator Friendly: Wind-pollinated; not insect-focused
Medicinal / Herbal Use: Culinary/decorative depending on type
Succession / Reusable Notes: Plant in blocks for pollination. Isolation may matter for popcorn/Glass Gem.
Zone 6B Notes: Needs warm soil and consistent water.
Companion Plants: Beans, squash, cucumbers, melons, pumpkins, sunflowers
Avoid Planting Near / Watch Outs: Tomatoes very close by
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: Plant promptly after frost once soil has warmed because Glass Gem requires approximately 110-120 days for fully dry, intensely colored ears.
Germination: Plant in blocks rather than a single row to improve wind pollination and kernel fill.
Harvest: Leave ears on plants until husks become dry and brown for the strongest translucent kernel colors. Fully dried kernels can be popped or ground into cornmeal.
Seed Saving: Glass Gem is open-pollinated corn and crosses readily with other Zea mays varieties. Isolate by distance or flowering time if preserving the characteristic multicolored seed population.
Special Care: Glass Gem is predominantly a popcorn/flint corn and is not normally eaten fresh like sweet corn.
Research Source: Native Seeds/SEARCH — https://www.nativeseeds.org/products/zp103 — Zea mays identity, 110-120 day harvest, 3-8 inch ears, 6-9 foot height and culinary use as popcorn or cornmeal
Research Source: Native Seeds/SEARCH — https://www.nativeseeds.org/pages/glass-gem-corn — classification as predominantly popcorn/flint corn and culinary use
[[RESEARCH ENRICHMENT END]]