Harvesting & Curing Onions in a greenhouse

Written by Jessica Davies

Onions are usually ready to harvest when the stems of the crop fall and or start to turn brown. We planted two onion slip varieties in mid April: Cabernet and White Candy. Onion slips are a great alternative to growing from seed. We didn’t have enough space in our seed starting greenhouse to start onions from seed, so we bought onion slips from Keene Organics, a local garlic and onion seed producer.

The past couple of weeks, I noticed that the onions should be harvested soon; the bulbs were emerging from the ground and the leaves we starting to turn yellow. We waited for a dry day to harvest all of our onions. Harvesting onions on a dry, sunny day will help mitigate any chance of rot while the onions are curing.

After harvesting all the onions, we set them aside in our greenhouse to cure. We laid them out on our greenhouse tables with the stem and skin still on. We turned on two large box fans and opened the sides of our greenhouse for proper ventilation. Curing onions in a greenhouse is a great option if you have a greenhouse, because this method will speed up the curing process by weeks. Curing onions in a greenhouse will require a few things, however.

You will need:

-70% shade cloth. (This is to block out a good amount of sunlight, because onions, like garlic, prefer a shaded curing space.)

-Greenhouse tables that allow air flow / racks. (It is important that the onions have as much airflow as possible.)

-Proper ventilation / fans. (Fans will help mitigate any chance of rot and speed up the curing process.)

Over the next few days we will rotate the onions by a few degrees so that the entire onion is cured and drys evenly. After about 2-3 weeks of curing in the greenhouse, the onions are ready for long term storage in a pantry or dry storage area.