The Journey of an Onion: Seed to Plate with the MSU Tollgate Farm Sustainable Agriculture Team

We are harvesting onions! Come along on the journey from seed to your plate.

It can take over 100 days from seed to harvestable bulb, so we start in February in the greenhouse. There was still snow on the ground, but the greenhouse was nice and warm for our onion seedlings to spend the first eight weeks of their journey.

Baby onions in our greenhouse

Next, we transplanted the seedlings out into our fields the last week of April. Onions require lots of water, sunlight, and minimal competition from weeds to grow large bulbs.

Onions are photothermoperiodic, meaning they are sensitive to temperature and day length. Onion varieties require a specific number of daylight hours each day for a certain number of days to form the bulb! There are three classifications of onion varieties: Long-day, which requires 14-16 hours of daylight per day, Short-day, which need 10-12 hours of sunlight per day and Intermediate or Day-neutral, which requires 12-14 hours per day. 

After the Summer Solstice, the onions start to sense the shortening of the days. The plants will stop forming leafy tops and start putting their energy into developing the bulbs. As the summer continues to wind down and the plant continues to focus its energy on the bulb, the plants show a physiological response known as “tops down” when the top of the plant falls over. The tops falling is a sign that the onion is ready to be harvested from the field.

For optimal storage quality, we must cure onions after harvest. Plants are pulled from the ground and left out in the field or moved to a greenhouse or hoop house. Curing decrease the possibility of neck rot, reduces water loss during storage and prevents microbial infection. Curing is complete with the neck of the plant is fully dry.

Onions curing

Once fully cured, we trim the onion roots and tops off and store the onions to distribute throughout the winter.

Next time you are at the store or farmer’s market buying an onion, remember the long journey it took to get to you!

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