When gardeners see their favorite lettuce start to bolt, it usually means it’s time to pull it and start over with another planting, but if your favorite lettuce happens to be an open pollinated variety, it can also mean it’s time to replenish your lettuce seed supply!
I’ve made a huge effort these past few years to save more seed from my garden from year to year. I’ve written quite a lot about the various reasons why, like how I am able to free up some of my seed budget so I can try a few new heirloom tomatoes every year, and how I hope to get better results from my favorite varieties from year to year with locally-adapted seed stock, but I think it bears repeating that seed saving is worth your time, particularly if it is a variety that has a permanent place in your garden from year to year. Over the past few years, I have gradually expanding my efforts, adding two or three new seed saving projects to my repertoire each year. After falling in love with Red Romaine lettuce last fall, it was kind of a no-brainer to make saving lettuce seed one of this year’s projects.
Lettuce seed is easy to save, but it does take a little time, space, and patience. A little planning ahead can be helpful if you are limited on space. The time from when the plant bolts until you can start to harvest seed is about one month, and then the seed harvest itself can last another month. During that time you will need to be able to accommodate a lettuce plant that will grow to be several feet tall and about a foot wide. You can harvest quite a bit of seed from one plant, so most home gardeners will be able to get by with leaving a plant or two in a convenient location and pulling the rest.
Always select plants that are slow to bolt and exhibit the best qualities, so those traits will be passed on to the next generation. You also need to make sure that the lettuce is an open-pollinated variety. Seed saved from hybrid varieties tends to revert back to one of the two original varieties that were crossed to create the hybrid, and may not look, taste, or perform as well as the variety you had hoped to grow again.
As the seed stalk emerges, there will initially be a heavier concentration of buds towards the top of the stalk, but you will also start to see additional, smaller clusters of buds start to emerge further down the stalk as well, and eventually each of these clusters will open up and spread out in the circular pattern you see above.
Once the plant starts to bloom, only a few flowers will open each day for a very short time. The flowering window is short–In fact, I missed the fact my plant was blooming for almost an entire week because the flowers didn’t start to open until mid to late morning and had already closed by the time I returned home from work in the afternoon!–but it gets the job done.
Lettuce flowers are self-pollinating, so you almost never need to be concerned about cross-pollination. That said, it can happen, so if you have more than one variety of lettuce going to seed at one time, and you want to ensure that you have pure seed stock, you may wish to separate them with a barrier or a little distance for good measure.
Flowering will continue with a handful of blossoms each day, and will continue for about a month.
You will also probably notice that the lettuce leaves will have changed rather dramatically during this process. They will be very thick and tough, and will excrete a very bitter milky sap if you tear into one. They are no longer palatable, with the age of the plant and exposure to hot temperatures having turned the sap extremely bitter as the plant transitions into seed production. The bud and seed heads may also have some of this same sticky substance (you can see a few droplets of it on the bud next the flower above).
After each flower has bloomed, it will close up once again (the purple teardrop-shaped pods you see in the photos) to develop the seed heads. It takes a couple of weeks for the seed to mature after blossoming, but then, just like the flowers, you’ll start to see the pods open up and reveal the feathery seed umbrellas.
The seed pods will continue to open in the same manner in which the plants flowered, with a handful of new seed heads opening up each day over the course of about a month. There will be some overlap with the flowering time, and there will be buds, flowers, seed pods, and seed heads on the plant all at the same time.
At this point there are a number of options for harvesting the seed:
Some gardeners choose to shake the entire seed stalk into a paper bag or a bucket every few days to collect the seed. It helps to allow the seed heads to sit for a few days after opening so they become brittle enough that the seed easily sheds without too much force. It takes a little practice, but once you get the hang of it, it works pretty well.
Others wait until at least half of the seed stalk has gone to seed and then cut the entire stalk and hang it to dry before harvesting the seed (unopened seed pods will continue to mature as the plant dries, but immature buds will not bloom). I tried this with a couple of small clusters, and the key to an easy harvest is to really let the stalk dry out for a few weeks (again, let the seed heads get brittle for easy seed collecting).
But I have found that the easiest way to harvest the seed is to simply harvest the entire seed head as they ripen. I simply pluck each one off (here’s where that sticky sap will get a little annoying, but it washes off easily) and collect them in a jar where I let them continue to dry. I feel like this method gives the greatest control over the degree to which the plants self-sow in the garden (not necessarily a bad thing, but it can but a kink in next year’s garden plans) and it’s also a good way to quickly harvest whatever seed is ready if rain is in the forecast.
The final step is to clean the seed by separating the seed form the other plant material. It separates fairly easily simply by rubbing the seed heads between your fingers to open up each pod and knock the seed out. Taking the task outdoors on a day with a light breeze can also help the process along (lettuce seed is light, so avoid really windy days), as will the use of seed screens if you want to be really meticulous about separating the seed from the fluff.
Lettuce seed is dormant for the first couple of months, so immediate seeding is not recommended. Instead, store your saved lettuce seed in the same manner that you would save your extra seed packets from year to year. If stored properly, lettuce seed will remain viable for at least 5 years.