Q. When do I know to harvest garlic, Walla Walla sweet onions, green onions and garlic?
A. Garlic should be harvested in our hot, dry climate when the tops have browned down by about 1/3. In other locations where it is not so hot they usually will harvest when the ½ of the tops have turned brown or when they fall over. We cannot wait that long in the hot desert.
There is a thin, tight “wrapping” around the cloves when you harvest garlic correctly. For appearance purposes and storage it is important that this wrap be continuous and tight around the cloves. If you wait too long before the final harvest, this covering starts to rot away, leaving the cloves exposed.
Sweet onions like Walla Walla are harvested when the tops have fallen over. Do not step on the necks to ready them for harvesting unless you plan to eat them fresh and not planning them for storage.
The drying down of the tops and tops falling over is a natural “sealing” process of the bulb. Stepping on the tops can allow disease organisms to enter the bulb because the neck has not dried down properly and may prevent any storage of the bulb.
Scallions are really nothing more than green or immature onions that have not yet begun to bulb, just barely started bulbing or cannot bulb. In the case of the Welsh onion, which is traditionally grown as a scallion, it cannot bulb up. White Lisbon onion is also grown as a scallion but this onion will bulb up if left in the ground too long. Harvest it before it starts to bulb.