If you have a garden full of lettuce, mesclun, and arugula, saving your own seeds is an economical way to propagate next year's crop. Saving seeds allows you to cherry-pick the varieties that perform well in your garden or heirloom varieties that are difficult to obtain. Over time, seeds saved from your garden adapt to their particular growing conditions making your seeds specifically suited to your garden, assuring a fruitful harvest.
Before you go to the effort of saving lettuce seeds, first, make sure to save seeds only from open-pollinated or heirloom varieties. Open-pollinated and heirloom plants both grow true to seed. Open-pollinated varieties are more genetically diverse, allowing them to better adapt to specific growing conditions. Heirloom seeds represent original varieties passed down from generation to generation, assuring their vitality. Some heirloom seeds have been documented as having come from a variety that's well over 50 years old.
Hybrid seeds, on the other hand, do not produce the same plant due to a phenomenon called "hybrid vigor" where certain characteristics outcompete others in subsequent crops. Saving and planting hybrid seeds is risky; there is no guarantee that the seedlings will be the same as the parent plant.
Timing the Harvest
Small, tender lettuce leaves are attractive to look at and delicious to eat, but when the plant goes to seed, it becomes gangly and unattractive as it bolts (sends up a flower stalk to produce seeds). The blooms resemble small dandelions and the plant becomes quite tall as if it's reaching for the sun. After a plant bolts, it's time to harvest seeds.
Waiting out this awkward growing cycle is hard to do for those who value garden aesthetics. The good news is that you don't need very many plants to produce seeds. In fact, one plant per variety will provide more than enough seed for next year's harvest. That said, camouflaging one or two bolting plants in your garden is easy to do. And you won't even see them if you plan your garden's layout with this in mind.
Most lettuces bolt when summer temperatures begin to rise. Once the plant sends up its seed stalk, the leaves become bitter and tough, making them unpleasant to eat. This marks the time when the plant will produce small clusters of flowers. These flowers contain the plant's pollen and will eventually produce a puffball full of seeds that, if left to its own device, will disperse to other parts of the garden.
If you are growing more than one variety of lettuce and they have bolted at the same time, you run the risk of cross-pollinating species. To prevent this, isolate each plant with a plastic bag or floating row cover to create a mini-greenhouse over each particular species.
You can also construct a cage covered in a screen and place it over an entire plant to isolate it from others. This assures the pollen of one flower won't be passed onto another variety to create a hybrid seed. If plants are situated more than 25 feet apart, you don't need to worry about cross-pollination occurring.
Harvesting Lettuce Seeds
Once the flower heads are fluffy and dry, it's time to harvest the seeds, and here are two harvesting methods:
- Hold a paper or plastic bag near the plant and every day shake the flower head into the bag until most of the ripened seed is harvested.
- Wait until most of the seed heads look ready to harvest, remove the entire flower stalk, and shake it over a bucket or bag to dislodge any fully-ripened seeds.
Both methods will work, but the first method takes more time and effort and the second method yields fewer seeds because you pull the plant before all seeds are ripe.
After harvesting the seeds, go through them and remove the fluff and chaff to isolate the seeds: pour your seed onto a shallow dish or tray and gently run a fan nearby. The breeze from the fan will blow away unwanted materials. If you don't want to use a fan, place the seeds and chaff in a bowl or saucer and blow on it gently. Once you remove the chaff, place your seeds in a clean, dry plastic food storage bag or mason jar, seal it, label it, and store it in a cool, dry place.