Supersweet Corn (sh2)
Zea mays var. saccharata
Twice as sweet, keeps a week, and the seed rots in cold soil if you rush it.
The sweetest, and the longest-holding
sh2 varieties (Honey n Pearl, Xtra-Tender, Mirai) have two to three times the sugar of standard corn and convert it to starch very slowly, staying sweet for a week or more refrigerated. That is why almost all supermarket corn is sh2. The trade is a crisper, thicker-skinned kernel with less of the creamy corn flavour some people prefer.
The seed is genuinely weak
The shrunken gene that holds sugar also makes a shrivelled, low-starch seed with poor energy reserves. It rots readily in cold wet soil and emerges unevenly. Wait for 65F soil - two weeks later than you would sow su - sow shallow at half to three-quarters of an inch, and do not soak the seed, which damages it.
Isolation is mandatory, not advisory
If sh2 is pollinated by su or se, or the reverse, the kernels come out starchy and tough and both crops are spoiled. Separate by at least 250 feet, or stagger planting so tasselling is two weeks apart. This is the single most important rule with supersweet corn, and neighbours' corn counts.
Block planting
Four or more rows in a block. sh2 needs good pollination as much as any corn, and gap-toothed ears are a pollination failure.
Feeding and water
Heavy nitrogen feeder - compost plus side-dressings at knee height and tasselling. An inch and a half of water a week, critically through tasselling and kernel fill.
Pests
Corn earworm, raccoons and corn borer as with any corn. Mineral oil on browning silks for earworm; electric fence for raccoons.
Harvest
Three weeks after silking. Because sh2 holds so long, the harvest window is much more forgiving - you can pick over several days rather than racing the starch conversion.
Storage
Five to ten days refrigerated in the husk, which is by far the best of the three types. It freezes well, though the tougher pericarp is slightly more noticeable frozen than fresh.
- Type
- sh2 - shrunken
- Days to harvest
- 70-90
- Soil temp
- 65F+ required
- Block
- 4+ rows
- Spacing
- 10-12 in
- Isolate from
- su and se - strictly
- Holds
- 5-10 days
- Seed
- Weak, sow shallow