When should I harvest my small grain forage?

Decide what balance you need between yield and quality, then watch those peas-and-oats (or other small grain forages) closely to harvest them at the desired growth stage.

Oats and peas nurse crop on alfalfa. Seeding at 100 lbs per acre, 38 days after planting.
Oats and peas nurse crop on alfalfa. Seeding at 100 lbs per acre, 38 days after planting. All photos by Jim Isleib, MSU Extension.

Michigan farmers plant small grain forages in two basic systems. One, as a nurse crop for a perennial hay crop such as alfalfa, or two, as a stand-alone annual forage crop. Harvest decisions depend largely on the system used. If the small grain forage is a ‘nurse crop’, then the effects of the harvest decision are based on what is best for the perennial hay crop underneath. Leaving the nurse crop in place too long can create serious competition for the developing perennial hay crop. 

Many farmers choose to remove the nurse crop as soon as the threat of erosion is past, with little regard for small grain forage yield. The development of glyphosate-resistant alfalfa varieties makes this approach much more feasible. Others wait to remove the nurse crop until the small grain reaches early boot stage. This approach provides reasonable forage yield and quality, and removes the crop in time to allow the perennial hay a good start before it becomes dormant. Finally, some will wait until soft, or even hard dough stage to maximize yield of small grain forage. In this case, there is a stronger possibility that establishment of the perennial hay crop can be negatively affected.

1.  King farm Goliath 1040 I 7.10.17

Oats and peas alone as annual forage at 150 lbs per acre, 67 days after planting. 

When small grains are planted for forage without a hay seeding, the decision is simpler. Former Michigan State University Extension forage specialist Dr. Doo-Hong Min had the following observations: “In general, there are three stages of maturity for small grains – boot, milk, and dough.The boot stage is the time when the head is enclosed by the sheath of the uppermost leaf.The milk stage is when the grain head releases a white liquid substance when opened. The dough stage is when the grain head begins to turn to a doughy consistency. As the plant matures from the boot stage to the dough stage, forage quality decreases while yield increases. If the goal is to harvest high quality feed, then small grains for forage should be harvested in the flag leaf to boot stage. In contrast, if high yields are the goal, then harvest should occur in the late dough stage. If a compromise is desired, small grains should be harvested in the early dough stage. If small grain harvest is delayed past the late dough stage, then the forage may be too dry to ensile. Since small grains can progress from boot to dough stage in a relatively short period of time, they must be watched closely to harvest at your target time.”

University of Wisconsin Extension’s Pea and Small Grain Mixtures includes the following information from a 1980’s three-year trial in Arlington, WI on oat/pea and barley/pea forage planted as alfalfa nurse crop:

Forage type

Cut date

Yield (lb/acre)

Crude Protein


Alfalfa yield during establishment year

Total 1st year forage yield

Oats alone

June 12







June 12






Barley alone

June 8







June 8






The bottom line with small grain forage crops is to know what you need in terms of yield, quality, and impact on your new perennial hay crop….and watch close!

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