How do you get lettuce to form a head?

I have some lettuce growing from a head I let bolt last year but it's not forming a head. Looks like a few leaves on a thin root.

what variety of lettuce?

some are loose leaf plants, and some are the head forming kind.

Romaine

hmmm, romaine should form a head. since it came up on it's own, it may not be fertilized enough to grow well. or it may not be getting enough sun.

we've certainly had enough rain this year, so it's not that.

They started to grow on 3-4 inch long thin roots so I burried then in the dirt to stand the plant up a little better. Anytime I grow lettuce from seed it blows. Only the plants already started, like from Lowes, grows real good.

my guess is your soil is well drained since you're not too far from "the shore", lol, so it's not a root rot problem.

since it's nothing but a green plant, it primarily need nitrogen. try adding a high n fertilizer.

i turn over a 12 foot by 3 foot row of soil, then make little troughs along it's length with my finger, removing any rocks. then i sprinkle a few packets of each type of seeds over the row in blocks.

i planted about 2 feet of kale (some of the seeds packs i bought were cheap, so there were very few seeds in each pack), 5 feet of romaine using 2 packs of seeds, and 5 feet of black seeded simpson using 2 packs.

then i just barely cover the seeds with 1/4" or less of a good, screened potting soil and wet it thoroughly but gently with a diffused watering can so it doesn't wash out the seeds.

you can try this method in a few weeks for a fall crop if you want. that is if summer ever gets here.