In the home garden, Romaine lettuce is best used by harvesting leaves from the base, a few at a time. Photo: homeguides.sfgate.com
Question: I have beautiful romaine lettuce plants that produce abundantly. I’ve been harvesting the outer leaves only and all is well so far. However, the bare lower stem is getting longer and the plants look less solid to me. I’m afraid they might snap off. What should I do? Should I mound some earth around the base the plant to shore it up?
Answer: Romaine or cos lettuce is, in many ways, the easiest lettuce to grow.
More heat-resistant than other lettuces, very resistant to slugs and extremely slow to bolt (go to seed), romaine lettuce will often produce leaves all summer if you harvest them the way you’ve been doing, by picking only the outer leaves of the plant, those at its base, a few at a time, like you would with Swiss chard.
This may fly in the face of the market garden tradition of letting the romaine lettuce mature, then harvesting it all at once by cutting it off at the base, which puts an end to the plant’s life, but then, you’re not a market gardener, are you? In the home garden, picking romaine lettuce a few leaves at a time is a perfectly viable way of harvesting fresh lettuce over a much longer period.
The flaw with this method is that you end up defoliating the lower stem over time, leaving the lettuce plant looking quite bare and top-heavy … although it’s not nearly as fragile as it may look.
If so, mounding up soil around the stem won’t give you much: lettuce doesn’t really root from the stem when you cover it with soil. However, what you can do is to cut the plant about an inch (2 to 3 cm) above the ground. (You need to leave a short stub.) This will stimulate the plant to regrow from the base and will soon give rise to new shoots that will become a source of fresh leaves. This is called the cut and come again method and it will work on most lettuces.
Note that cutting back must be done before the plant starts to go to seed (that is, before the flowering stem begins to lengthen and leaves become bitter and produce milky white sap). Once the plant has started going to seed, the harvest of that particular plant is over and you’ll have to start new plants from seed.