Spring Hay Harvest Timing

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

When deciding on the time for the first hay harvest of the new growing season, a number of factors come into play. First and probably foremost among these is the question of whether to delay harvest until the grass or legume hay crop is in full flower to obtain the maximum amount of yield possible or to harvest early reducing yields but gaining in quality. That is a question each hay grower will need to answer for him or herself. If the hay is for your own operation, which do you need? – high quality or more quantity? If the hay is to sell, have your buyers demanded real quality in the past? or just pseudo-quality (a green color to the hay, fresh smell, and hay free of dust and mold)?

If quality rather than strictly quantity is your goal, then you need to be aware that at least historically the first half of May offers the best chance of good hay making weather we’ll have before mid- to late-June. I’ve come to the conclusion that rather than relying on the weather forecasters you have an equally good chance and maybe even a better chance of predicting the possibility of rainfall or poor hay making weather in your location if you examine the national weather maps and look for patterns indicating a chance for good weather. We’ve become so dependent on what the weather forecaster has to say that we tend to ignore our own brain’s ability to interpret the weather maps and create our own forecast.

So what happens if you have hay making weather and you decide to harvest your hay early? Remember that as the grass or legume crop goes from vegetative growth into the reproductive stages, yield, fiber components, and lignin increase and crude protein, digestibility, and palatability (intake) go down. The closer the crop gets to flowering the more rapid the decline in quality and the more difficult it can be to make quality hay. In part, this is because as tonnage per acre increases, the time it takes to dry the hay increases. Hay left in the field for longer periods also increases the risk that it will be rained on and cause even further declines in hay quality.

Perhaps the easiest crop to make the timing decision on is alfalfa since it is often near the ideal stage for harvest in early to mid-May in most years. We already make use of early harvesting on alfalfa if we find that alfalfa weevil is becoming a problem since the early harvest often solves the problem. In addition, alfalfa tonnage can rapidly increase with a delay in harvest and cause all kinds of drying problems.

A more difficult decision surrounds many of the grass hays that we use. Orchardgrass although it may have some seed heads visible is not approaching its maximum yield potential yet. Early harvest with this crop will result in excellent quality hay (if not rained on) but yields will be low. The second harvest will be heavier than normal and many of the side, younger tillers of the plants will produce seed heads, boosting yield and making the second harvest appearance more like the first harvest. Depending on the time of harvest for the second cutting, the quality may be a little below that of the traditional second cutting orchardgrass but should still be very good. The total tonnage of the two harvests when the first one is taken very early will not be as high as that for the typical almost mature late first cutting and leafy second cutting system.

Kentucky bluegrass in many areas is approaching full head emergence so the first half of May harvest for this crop will work fine. Similarly, the ryegrasses should respond well to this early cutting system when weather permits growers to harvest in May. Timothy harvest in Delaware seems to vary greatly so scout the crop carefully to assess its stage of maturity. When the heads are mostly emerged but still relatively small and not yet flowering, you’ll be at the point that is the best compromise between quality and quantity.


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