This is one of those ideas that is insanely simple yet effective. Grow a couple of lettuce varieties with pretty leaf shapes and bright colours. Put them together in a container that sets off their leaf colours or grow them in individual pots of a contrasting colour. In this case I have two leaf lettuce varieties with very curly leaves and contrasting colours (‘Ruby’ and ‘Henderson’s Black-Seeded Simpson’) set off by a black metal container. Hint: Chartreuse and yellowish greens always looks good when paired with deep reds or purple.
The key to keeping lettuce happy on a hot deck is to move the container to a less intense spot when the heat of summer kicks in and make sure to keep the soil moist — they’ll get bitter faster if they experience too much drought. You can cut each leaf off individually (remove from the outside if you want to keep a nice rosette) or just chop the whole thing off about an inch or so from the soil line and set the plant aside (somewhere less visible unless you’re comfortable with the stubby bits on display) until it grows back a second harvest.
By the end of the second round the leaves are usually too bitter to eat. Don’t toss it out into the composter just yet! You can still get some use out of your lettuce by setting the plant into hotter sun (don’t forget to water!) and allowing the plant to bolt. Bolting is when a plant produces flowers and then seeds prematurely in a mad rush to reproduce itself when the growing conditions become too extreme. This is usually caused by the increasing heat of summer and intense sun. The colour will often deepen in hotter sun and some lettuce varieties will grow into crazy, alien towers with pretty flowers perched on top. Don’t bother trying to eat it at this point since it will taste horrible and ooze a gluey substance when cut, but it makes a very cheap and easy bright spot when set amongst boring edibles like tomatoes and potatoes.