In determining whether to make hay, know how much you can harvest and at what point you’re considering mowing.
A potential shortage of stored forages means that producers may have to make tough decisions when it comes to late fall forage management. Extreme weather may keep forage growers out of their fields or provide less than expected yields during the spring and summer. However, they then may be faced with the need to decide about late season hay harvest – should you mow or let the forage stand in the field?
Fall hay management can be a “make-or-break” time for stand longevity and subsequent forage yields Managing grass stands is not as challenging as legume stands. The main consideration in determining whether to mow a grass field is how much forage is standing and at what point in the fall you are considering mowing. If there is considerable regrowth that accrued during the summer and early fall and you were unable to maintain a regular harvest schedule, assess your forage stand to determine if you should mow in the late fall.
Regardless of whether the hay field is grass or legumes, residual height should be a primary concern for the last cutting of forage. Ensuring proper residual height will give the forages adequate leaf material to photosynthesize and regrow top growth as well as store carbohydrates at the base of the plant to overwinter. Grasses should not be cut lower than 4 inches in the fall, and a residual height of 5 inches or greater is preferred.
Another factor to consider is if your crop has foliar, crown, or root diseases. For many of the pathogens that cause these problems there is a risk of disease in the subsequent growing year as the pathogen(s) can often overwinter in plant biomass if environmental conditions are favorable. Some examples of these include crown rust, stem rust, and leaf rust of cereals, as well as brown stripe of orchardgrass. More information on grass diseases see the Penn State Extension factsheet on "Identifying late season diseases in forage grasses" .
Grazing a hayfield can be more economical and is a way to extend the grazing season. These hayfields can be “stockpiled” and grazed after the growing season ends and the need for stored forage is reduced. By allowing the livestock to “harvest” the forage, labor needs are reduced, the cost of harvest is lower, and the need for hay is less. If you plan on grazing a hay field, it is important to implement a strip grazing system .
For more information on fall forage management for both grasses and legumes, please see Fall Forage Management and Fall Pasture and Grazing Management .