When the grain is ripe, the plant still has green foliage. You should not wait for the foliage to dry to harvest it.

Sorghum reaches the stage of physiological maturity when the grain’s water content is around 35%. It is possible to harvest from 30% humidity but in general the grain’s desiccation is quick and the harvest begins from humidity level between 18 and 25%.

Keep in mind:

  • Around 20% humidity, the panicle’s branching begin to dry and become looser (panicles open)
  • After reaching 18 or 20% humidity, the water contents of grains can increase again in case of unfavourable weather conditions (rains, fog).
  • When the grain is ripe, the plant still has green foliage. You should not wait for the foliage to dry to harvest it. However, a significant drought in the autumn and/or early frost can lead to a quick desiccation of the plan and come with lodging if harvest does not occur soon enough.


  • Harvest as soon as September if humidity is lower than 20%
  • After September, do not delay the harvest to obtain very low humidity grains, given that the rewetting risks increase and the grain’s quality can be altered by the strong ambient humidity (fog). Delaying the harvesting date also increases risks of lodging.
  • Do not pick up too many stalks and leaves (slowing down the harvesting rhythm and increase the humidity level of the grain).


The harvest must be done as soon as the first signs of the plant’s lower leaves drying.

The objective is to harvest silage between 27 and 30% DM to obtain quality silage, a silo that does not spill, good conservation and maximal performance of the silage. More generally, sorghum silage must not be cut too thinly or too coarsely to guarantee good silo stability when it is opened.

Keep in mind for grain varieties

  • When, in the middle of the panicle, grains reach their milky-pasty stage (the panicle often changes colour then), this means the grain has 50% DM, or around 30% DM for the whole plant.
  • On a sorghum panicle, the maturity of grains can greatly vary between the top and bottom grains, with some grains already passing the milky-pasty stage. Those grains will bring good value to small ruminants, but less for beef cattle. As these grains remain whole, their degradation will be difficult during rumination, and will be found again in manure. The digestibility of whole grains is reduced under a certain DM threshold and contributes to lower the total digestibility of silage.
  • If the DM content of sorghum is above 32%, it is possible to mince it thinner, or to use the grain processor to improve silage digestibility.

Keep in mind for varieties without grains (male-sterile or day-length sensitive)

  • It is more complicated to determine the right silage stage for sorghum without grains.
  • The state of the plant’s lower leaves is a good indicator: ensile as soon as they give signs of drying.
  • Twist the stem to check the minimal DM content: as long as sap flows, sorghum has not yet reached the 27% DM threshold guaranteeing the silo will not spill.

Keep in mind for varieties without panicle and of day-length sensitive (PPS) types

  • It continues to accumulate biomass late.
  • It is therefore advised to keep the crop in the field as long as the weather in favourable to plant development, in order to fully take advantage of this late production potential (until the lower leaves begin to dry).