A barrel is a great way to grow vegetables if you do not have enough space for a garden. The barrel is deep enough that you can cut it in half and make two planters since most vegetable's roots are not that extensive. As long as you have a good sunny spot, you should be able to grow some nice vegetables in a barrel.
Drill holes in the bottom of the barrel so the water can drain. You can do this with a 3/8-inch drill bit to keep the soil from washing out with the water. Tip the barrel over to drill out the holes.
Fill your barrel or half-barrel with potting soil. You can use ordinary garden soil, but the barrel will get so heavy you will never be able to move it. Use a mix with perlite, vermiculite, spagnum moss and/or peat moss that will hold the water without too much weight.
Set upright plants like onion sets, spinach, Swiss chard, or carrots in the middle section of the soil. Bury the roots of the plants the same depth as they were in their original containers.
Plant seeds just under the surface of the soil, if you choose to save money instead of buying plants. You can crowd them pretty close together since you do not need to leave any room for walking or weeding.
Plant vine vegetables around the outside edge of the barrel. Dig 4- to 6-inch holes in the soil next to the inside edge of the barrel and place trailing vegetable plants like cucumbers, cherry tomatoes, chili peppers, green beans or peas in them. These plants can grow down the outside and onto the ground below.
Find interesting colors of lettuce to fill in gaps between the center plants and the outer edge plants. Even quick growers like radishes and beets can fit into a barrel garden. Sow some seeds in the empty areas and, within a week or two, they should sprout.
Pop in a few herbs like basil, cilantro or parsley when the quick growers are finished. They will continue to grow for the rest of the summer and even though crowded on the top surface of the barrel, their roots will have plenty of room to grow downwards.