I use a full spectrum High intensity light. I ordered it from one of the catalog’s on sale. IIRC, Jumpstart lighting kit. Has a stand for the light, and I put it on an old micro wave table in front of a patio door.
My poor little lettuce bunch has survived a trial by Fire-and-Ice, no thanks to my beginner's ignorance. First it sat too long under 8" of sudden snow. Brought it in to warm up; fast snow melt, then back outside to get some real light. End of sunny day found a mass of dead-looking wilted mess, brought back inside, soaked well, figured I've surely killed it. Half hour later, it appears the little bunch has survived in spite of me. Every dead leaf came back and plumped up.
Then I ordered a proper light.