Some Alfalfa Establishing Poorly

By Marvin Hall

Reports from Pennsylvania and New York indicate that some spring seeded alfalfa is struggling to establish.

Poor establishment of spring seeding alfalfa has been widely reported across Pennsylvania and New York. The alfalfa germinated and emerged but then just seemed to stop growing. In some cases, six week old alfalfa was still in the unifoliate leaf stage. Then when the temperatures got warm, some of the plants grew out of it but others just aren’t as thrifty as we would expect.

The unifying factor in these poorly establishing fields is timely planting, cold conditions, and some late frost. It appears that fields that were planted later avoided those conditions and are establishing fine. While some farmers report plants actually disappearing from the stand, other report that the plants are there but just not growing.

What to do?

Control weeds. This has been a challenge because the alfalfa was too short to be treated with herbicides. On some of my research fields, we have resorted to chopping off weeds and alfalfa to get sunlight down into the alfalfa. Hopefully, this will stimulate the alfalfa to grow and provide a good harvest in July.

Should you replant?

Not now. As we enter the hot and dry part of the summer it is not a good time to be trying to establish alfalfa. Keep the seed in the bag. Control the weeds and monitor the stand. If you have 15 plants/ft2 at the end of July then there should be sufficient plants to justify keeping the stand. If you are below that plant density, then killing off the stand and replanting in August or early September is recommended. Alfalfa auto-toxicity is unlikely in these fields.

Source:psu.edu