I started a mini windowsill garden last week.
What I did was save the short stalk end of the Romaine lettuce, put it in about a half-inch of water, and place it in a sunny window. I change the water every day. The progress is as follows going clockwise from the top Chobani container: Sunday – April 28, Tuesday – April 30, Sunday May 5 and Friday – May 3. The first Romaine stalk I started is in the Chobani yogurt container. I experimented with the clear vs. opaque containers to see if it made a difference. Apparently it does.
I can cut and use the lettuce and start the process all over again until the stalk sends out a thick seed shoot, then I need to find a new stalk and start over. I read someplace that these can also be started in the ground but I have a lot of rabbits and doubt I would get any produce before they nibbled it all up.
I understand you can grow celery this way as well.
Will this mini windowsill garden keep us in Romaine lettuce all spring and summer? I doubt it. But it’s fun to watch it grow.