When Should I Harvest Alfalfa
Dwain W. Meyer
The prime objective in determining when to harvest is to obtain prime hay in the bale. This is especially true for cash hay producers and dairy operations where prime hay means greater net returns for the alfalfa crop, but it can be important for beef cow producers also as a source of high-quality high-protein hay to be used in rations with other low-quality hays like mature grasses or slough hay.
Many factors enter into the decision of when to harvest alfalfa such as environmental conditions, other field work, insect infestations, etc. But what factor(s) should be used to determine when to harvest if these are not determining factors?
Plant maturity or calendar date has been used extensively to determine the optimum time to harvest, but I believe plant height is more important in determining when to harvest than plant maturity and especially calendar date. The growing season changes the optimum time to take the first cutting. If the spring is late and the temperature average to below average, high-quality hay can be obtained by harvesting alfalfa at a later maturity stage, late-bud to early bloom, like in 2008 in the Red River Valley of the North when harvest started on June 16. But if the spring is early and above-normal temperature, the optimum harvest stage will be earlier like in 2002 when first harvest was taken on May 24.