Q: I am growing butterhead and iceberg for the first time. Can anyone tell me why the iceberg leaves are all wide open? I thought head lettuce grew in a nice tight ball? Am I supposed to tie it up like the cauliflower?
You’re right that iceberg, a popular crisphead type lettuce variety, do indeed form tight heads as they mature. Lettuce is generally a pretty easy-going crop and they’ll do this on their own without intervention from us. However, there are conditions that can prevent this particular type from forming a proper head. Before fretting too much, I would first consider time as a factor. You don’t say how long yours plants have been growing. Crisphead types like iceberg are akin to cabbage in that they start out looking rather loose when young, and mature into their final, tighter form as they reach harvest time. I generally don’t start to see a tighter head develop until my plants have grown well past the halfway mark (35-40 or so days from seed).
That said, like all leafy veg, lettuce reaches its best potential when the soil is rich, loamy, and consistently moist, but with good drainage. Nitrogen is especially important in healthy leaf development. Crispheads that are grown in poor, compacted, or nitrogen poor soil tend to develop small, loosey-goosey heads. If you think soil could be the problem, I’d suggest scratching a handful of compost, manure, or vermicompost (aka worm castings) into the soil around each plant. Use a light hand to avoid damaging developing roots. This will add nutrition and help break up compacted soil. You can also try watering every two weeks with a weak solution of fish emulsion diluted in a watering can. The next time you plant in this spot, work a lot of compost into the soil before seeding or setting out transplants.
Lack of sunlight can pose another potential problem in head development. Lettuces are notoriously adaptable to low-light conditions, but head-forming varieties do tend to under-perform in these conditions. Potted plants can be moved around with the sun, but if your plants are in the ground, your best bet is to scale back your expectations and use what you’ve got. Both crisphead and butterhead varieties are perfectly edible at any size. Snip off the leaves individually while young, or allow the heads to form as best as they can and eat them then. They’re still going to be great at any size. In the future, I’d suggest growing a leaf lettuce variety such as ‘Red Sails,’ ‘Black-Seeded Simpson,’ & ‘Lolla Rossa’ in shadier spots and saving the crispheads for the sunniest part of the garden. In fact, I’d suggest growing both simultaneously so that you’ll have a range of flavors, sizes, and shapes to harvest for salads throughout the season.
Garden authority Gayla Trail is the creator of YouGrowGirl.com.