If you have a patch of earth you can grow something in it, as long as you tend it well enough. But for many people who have limited space there is only a yard with a stone surface. No matter what size the yard is, it is the surface quality that limits the space. Of course, a courtyard can be the scene of a container garden,whose containers are sizable stone or brick enclosures in which trees can grow. It can also contain large pots capable of taking shrubs. But few of us have a courtyard. For most of those with just a yard, there is the possibility of using containers, but for some growers pallets are an option.
There are two ways of using pallets. You can make a container from four of them knocked together. Often the pallets are cut down in size to make them more manageable, often they are cut in half, as you do not need great depth of soil for many vegetables. The inside of the pallet box will be lined with plastic or geo-textile to hold in the soil. It is also useful to insert water pipes to take water to the depths of the pallet container.An over-spill pipe placed about five sixths of the way up is also valuable, as all containers are prone to flooding in severe rain storms,and this will prevent complete waterlogging.
Yet pallets often go with pallet collars, which are flexible, hinged containers fitted over pallets to enclose the goods that they carry. Their uniformity of design means that they are intended to be stacked one atop the other,so many gardeners use them to create raised beds. In the picture below you will see how I use pallet collars on my allotment.
Yet pallets can be used vertically. Again the base of the pallet needs to be covered with black plastic or geo-textile, firmly affixed with staples, and the spaces filled with soil. It is then placed on its side,possibly affixed to a wall, and the seedlings inserted into the spaces. Watering can be with a spray. As with all containers the soil nutrients quickly run out, so regular use of fertilizer is necessary, but as I have said before, not in excess.You do not need large amounts. But all containers tend to dry out quicker than the soil does, so you need to keep an eye on their moisture levels.
Heavy plants are unsuitable for this vertical growing, so it is better to grow lighter plants such as the great range of salad vegetables that is available. Keep the heavier vegetables for the containers that lie flat on the ground.