Q.when is leaf lettuce mature enough to eat?
How do I know when a leaf lettuce is mature enough to eat? This is my 1st time gardening. I decided to do a leaf lettuce combo but I’m not sure how to tell when the leaf is mature enough to cut off and eat. I bought it after it sprouted and planted it in raised bed. It’s been about 3 wks or so.

What lettuce did you plant? Green and red lettuce, butter head lettuce, stem lettuce or romaine lettuce? Each is a little bit different on when they are fully ripe.
I will discuss green and red lettuce here. If you like baby lettuce for their more delicate flavor, you can harvest when the outer leaves are only a couple inches tall.
However, if you are interested in more mature lettuce, which is rich-colored, well-ruffled and deeply lobed, then green and red leaf lettuce varieties should be examined 50-60 days after planting or when the outer leaves grow 4-5 inches tall.
If you have other lettuce varieties, you can read the article below to determine their ripening times:
http://homeguides.sfgate.com/tell-lettuce-ripe-74516.html
For more information on harvesting leaf lettuce, please visit the following link:
https://www.gardeningknowhow.com/edible/vegetables/lettuce/harvesting-leaf-lettuce.htm