Posted by Sunset, April 12, 2009
By Johanna Silver, Sunset test garden coordinator
He's advised me on potato fruit and garlic harvesting, and now Greg Lutovsky from Irish Eyes Garden Seeds has done it again -- this time explaining the world of green onions (or scallions).
We received a question on our message board from a gardener named Sarah, inquiring about the seed heads (flowers) forming on the top of her green onions. I decided to give Greg a call to get the full story on how onions go to seed -- any excuse to learn way too much about a particular crop.
Sarah's seed-forming scallions
All onions are biennial, meaning they go to seed in their second year. In this case, the green onions lasted a summer, a fall, and a winter, but started to form seeds as winter came to an end. Sarah hastened this process by repeatedly using her scallions as chives (snipping the stems). This injured the plant and made it defend itself by going to seed sooner than later. No judgment from my end, Sarah, I promise. I've had my own troubles with onions.
Green onions are no longer edible once they start going to seed. The stalks become woody and tough.
Being the curious gardener that she is, Sarah wondered about saving the onion seed.
There are a couple of problems when saving your own onion seed. The first is that they won't come true to their parent plant unless there are no other onions (or only onions of the exact same variety) in a two mile radius. Onions are bee-pollinated, and bees can typically fly two miles. Greg manages this challenge by having 100 certified organic acres scattered on small plots that span over 12 miles. He further ensures no cross pollination by supplying all of his neighbors with free seeds of the varieties that he's growing that season.
Even if Sarah does save her seed (maybe she'll breed an award-winning variety) the next challenge will come with harvesting the seed. She'll have to wait until it's done flowering and then snip off the spent bloom when black seeds are visible. The black ones are fully dried and ready to plant, but there will be many seeds fully mature. These will need to be dried on screens and then thrashed out of their husks. Greg says that she could do this by wearing sturdy, rubber gloves and rubbing her hands together vigorously with seeds in the middle.
Be sure not to just leave the flower on the stalk until all the seeds are dry, as they will inevitably fall off and blow away.
Take home message: Use your green onions before a year has passed. I know it's tempting to leave them in the ground because they keep so well, but go ahead and pluck them before it's too late. Plant new successions in the spring and fall to keep a steady, year-round supply (depending on your climate, of course).
Here is onion information from the Sunset Plant Finder.
And here is an update: Sarah doesn't actually like onions (hence leaving them in the ground so long) and there's no way she'll be going through such an involved process to save those seeds. She's planning to use the patch for something more loved.
Good luck, Sarah!
