Corn is generally ready to harvest when the kernels have matured to the dented stage, and a milk line inside the kernel moves to the base, forming a black layer. This indicates maturity. Another key indicator is the moisture content of the kernels, which farmers typically check; corn is usually harvested when moisture is around 17% or less. Additionally, the corn plant changes visually: leaves dry and turn yellow, ears tip downward, and the silks turn brown and brittle. For sweet corn, the kernels should be milky white when pricked, and the ear feels soft with a blunt tip. The harvest time varies with planting dates and weather but commonly falls around 75 to 100 days after planting, often from late summer to early fall in temperate regions. Here are more specific signs to know when corn is ready:
- For field corn: The dent stage on kernels, milk line reaching kernel base with a black layer, moisture around 17% or less, and drying plant leaves.
- For sweet corn: Silks brown and dry, kernels milky white on puncture, ears soft to touch, and blunt ear tips.
- Timing after planting is usually 75-100 days or late summer to fall for field corn; sweet corn is typically picked earlier when the kernels are juicy.
Farmers also use sensory clues like tasting kernels for their starchiness and texture, combined with moisture testing tools for precision.
