Taking Another Alfalfa Harvest

Depending on how much forage is in the field, you might be considering taking another alfalfa harvest this fall. Taking a harvest between now and a “killing frost” will add extra stress to the alfalfa plants and increase the risk of weak or thin stands next spring.

Another option would be to wait until after a “killing frost” to take that final harvest. This practice tends to be less risky to the alfalfa stand than harvesting between now and the killing frost. However, knowing when frost has stopped alfalfa growth is tricky because you do not want a warm period after harvesting and the alfalfa to begin growing again. Below are some things to consider when assessing the risks of taking a harvest yet this fall.

• Age of stand: Older alfalfa stands are more likely to winter kill or suffer winter injury following a fall harvest than younger alfalfa stands.

• Variety: Alfalfa varieties with moderate resistance to several diseases and sufficient winterhardiness have greater tolerance to stress from fall harvesting than less disease resistant or winterhardy varieties.
• Soil pH and fertility: Adequate soil pH and fertility minimizes the risk of fall harvesting by allowing alfalfa plants to develop properly and be healthier.
• Soil drainage: Alfalfa on well-drained soils is less likely to suffer winter injury than alfalfa on poorly-drained soils.
• Harvest frequency: Alfalfa harvest schedules which do not allow the alfalfa plant to flower once during the season, predisposes the plant to winter injury.
• Dry conditions in August: Dry weather, especially in August, causes alfalfa to store excess root energy reserves making it more winterhardy.
• Fall cutting height: Leaving six to eight inches of stubble when taking a fall harvest will reduce the risk of winter injury.