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When is maize ready to harvest?

Advice from our specialist Advice from our specialist6-9-2019

Forecasting the expected date of maize harvest is extremely important to maximise crop value as well as planning rotations. Harvest date is mainly determined by the variety sown and the season.

Maize harvest is influenced by geographical area, site, vareity and the dry matter content of the crop. When assessing a crop it needs to be checked in several locations and not just the perimeter.

Afbeelding: Webp.net-resizeimage (14)
Clive Edmunds with Robert Cross

When the dry matter content of the crop is 28 – 35% then the crop should be harvested. This is when the leaves level with the cob and begin to turn brown and the leaves at the top of the plant are becoming pale and papery. When a plant is picked and the stem twisted, no juice will emerge.

Maize DM table

Thumb Nail Test

For a quick in field assessment of crop maturity the thumb nail or the milk line test can be used. If you peel back the sheath on the cob the grains at the top of the cob should have a consistency which is comparable to soft cheese, whilst the grains at the bottom should be like hard cheese. Graind in the middle should just be able to take the imprint of a thumbnail.

Milk Line Test

Break the cob open half way down and rmove on of the grain kernals. The milk line is where the solid starch ends and the liquid milk begins. The ideal is to have a 75 – 100% of the kernal yellow in colour (starch) instead of being milky and for no liquid to be excreted when pressed.

Maize - Milk Line Test


For further information on maize, please contact your local ForFarmers Forage Specialist or call us on: 0330 678 1200