Glass Gem

Corn

Zone 2b Save Garden

🌱 90d to harvest Upright

Feel the glassy shimmer before you even harvest—Glass Gem corn forms jewel-bright kernels that catch the light like faceted opal,…

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	May 15th
Transplant / Sow Outdoors	May 15th
Harvest Begins	Aug 13th
Harvest Ends	Aug 25th

Crop Details

Trait	Value
Days to Maturity	90
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	60
Min Soil Temp (°F)	55
Min Night Temp (°F)	28
Harden Off (days)	Not Required

Recommended Companions

Yamato Sanjaku Cucumber

Kalunga Cucumber

Moonsong Deep Orange Marigold

Parisian Pickling Cucumber

Beit Alpha Cucumber

Gagon Cucumber

Frequently Asked Questions

What pest or disease most often affects Zea mays var. saccharata (glass gem corn), and what should I do?

Watch for corn earworm (Helicoverpa) once silks appear—damage often starts at the tip of ears. Apply a labeled BT (Bacillus thuringiensis) product or an earworm-targeted corn insecticide following the label timing when fresh silks first show and repeat as directed. Also remove and destroy any visibly moldy or rotting ears early to reduce spread of ear rots (common in humid weather).

How often should I water glass gem corn during the main growing phase?

During active growth (after plants are established and before ears mature), keep soil evenly moist with about 1–1.5 inches of water per week, increasing during hot spells. Water deeply so moisture reaches the root zone, especially around tasseling and silking, because inconsistent moisture then can cause poor kernel set. Mulch to reduce drying, and avoid letting the soil swing from very dry to waterlogged.

How can I tell when Zea mays var. saccharata (glass gem corn) is ready to harvest?

Harvest when silks are brown and dry, and kernels look fully developed, tightly packed, and glossy—typically around 80–100 days depending on conditions. Press a kernel with your thumbnail: it should release milky “juice” (not clear water), and the kernel color should match the variety’s mature jewel-like pattern. For the best sweetness and tenderness, pick in the morning and use soon after harvest.

Feel the glassy shimmer before you even harvest—Glass Gem corn forms jewel-bright kernels that catch the light like faceted opal, with a spectrum of amber, cream, rose, and deep blue-green. The kernels are pleasantly tender with a sweet, fresh snap, making them a standout for showy fresh use and for vibrant color in seasonal displays, salsas, and pickled accents. Grow it for the garden spectacle as much as the flavor—each ear becomes a living mosaic ready to brighten your table.

Sowing Tips

Transplant Conditions

Wait until soil reaches 55°F and nights stay above 28°F before moving outdoors.

Expert Note

Plant in a block (not a single row) so wind pollination is reliable for full kernel set and best cob development.