I have been using containers for a few years now. My preferred container is "molasses tubs". Containers about 30 gallons or so that originally contained supplemental feed and usually molasses in some form for cattle. They also last a long time as opposed to the small planter pots that you get from Lowe's.
Lots'a cattle raisers use this for supplemental feed during the winter. The tubs are trash to them when empty and will give them away for free. Others collect them and sell them for $5-10 each.
However you aquire them, they make great pots for larger plants/plantings. I do my greens/lettuce/spices in them as I can place them close to the house versus the garden which it a lot further from the house. My lettuce, grown during the winter as it gets too hot for lettuce during the summer. I just sprinkle a lettuce mix seed and let it grow. Picking off it just about every day as needed. Same for greens and spices. Right now I have kale, green onions, basil, dill, oregano and sage on these pots.
As an experiment I am trying a "self watering pot" method. The name is somewhat misleading as you still have to water the pot but it supplies a steady supply of water to the plants along with air pruning the roots, which promotes plant health (supposedly, jury's still out on this one). Google this on Youtube for more info.