I hope I have persuaded some of you to look into the possibilities of using concrete mixing tubs as containers for plants. Once you fill the container with soil, that's it!
After a couple years use, you can amend the spent soil with a rich compost top dressing. After harvest, you can keep the tub covered with plastic. This will keep down weeds and help the soil warm up faster come spring.
I've grown lots of different shallow rooted vegetables in these tubs. One year, I grew about 10-12 different varieties of lettuce in them. I had some very nice salads that year.
I detest cooked spinach, but I discovered a few years back that most sandwiches are far better when made with cold, crisp spinach than they ever were when made with near tasteless iceberg lettuce and healthier, too. Iceburg lettuce has few nutrients.
If you have a hankering to grow stuff, but feel you don't want to be a full fledged gardener, consider some loose leaf lettuce or spinach in one of these tubs. I think you will be pleased.