Corn Kernels Dented: Late Harvest and Kernel Types
Corn kernels dented or doughy on a sweet corn ear usually point to late picking. Extension guides tie quality to the milk stage.
The short answer
Iowa State says sweet corn is ready at the milk stage when kernels give a milky juice. Overmature ears are tough and doughy. Purdue lists dent corn as a separate field type. USU says isolate sweet corn from field corn. Pick about 18 to 23 days after silks appear.
Why do sweet corn kernels look dented?
Iowa State says overmature sweet corn turns tough and doughy. Purdue explains that the sugary gene slows the change from sugar to starch as kernels fill. Past the milk stage, starch builds. Purdue says kernels will pass the period of maximum sweetness and start to dent. Purdue also notes dent corn is a field corn type that shares diseases with sweet corn.
Milk stage: milky juice in kernels. Past milk stage: tough doughy kernels. Dent corn: field type.
How do you tell when sweet corn is ready?
Iowa State says the silks turn brown and dry at the ear tip. A punctured kernel gives a milky juice. Clear watery juice means an unripe ear. Mississippi State says silks turn very dark brown to black. It gives 17 to 25 days from first silk to harvest.
Brown dry silks: near harvest. Milky juice: ready to pick. Warm weather: matures in 15 days or less.
Do kernel types change texture?
USU says standard sugary corn converts sugar to starch within a few days of harvest. Sugar enhanced types hold it a few days longer. Shrunken 2 types have up to twice the sugar. Older shrunken 2 varieties can have a tough kernel skin. USU says isolate sweet corn from field corn by 250 feet or 14 days.
| Option | What it does | Source |
|---|---|---|
| Standard sugary | Fast sugar loss | Classes of sweet corn |
| Sugar enhanced | Holds sugar longer | Classes of sweet corn |
| Shrunken 2 | Store 5 to 10 days | Classes of sweet corn |
Troubleshooting
Doughy kernels: a late pick. Harvest at milk stage.
Watery kernels with gaps at the tip: ear picked early. Wait a few days.
Starchy kernels in sweet corn: cross pollen. Isolate from field corn.
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Sources
- When should I harvest sweet corn?, Iowa State University Extension, Yard and Garden
- When should sweet corn be harvested?, Mississippi State University Extension
- Classes of sweet corn, Utah State University Extension
- Sweet corn (NCH-43), Purdue Extension
FAQ
How do you tell when sweet corn is ready?
Iowa State says the silks are brown and dry at the tip. A punctured kernel gives a milky juice.
Is field corn the same as sweet corn?
No. Purdue says the sugary gene in sweet corn slows the change from sugar to starch. USU suggests isolating sweet corn from field corn.
How long from silk to harvest?
Iowa State says about 18 to 23 days. Mississippi State says 17 to 25 days.
Why does corn lose sweetness after picking?
USU says standard sugary corn converts sugar to starch within a few days after harvest.
What do su se and sh2 mean?
Purdue says su is the sugary gene. Se is sugary enhancer and sh2 is shrunken 2, both used in high sugar corn.
