Nearly any vegetable from carrots and lettuce to tomatoes and even corn can be grown in a container. Large containers like an old cast-iron tub provide plenty of room and can be incorporated into a fun landscape. Plant the vegetables in the spring after the last hard frost, just as you would if you were planting them in a garden.
Remove the drain pipe and the drain screen. Enlist the help of some friends to move the tub to a sunny location where the vegetables will receive at least six hours of direct sunlight. Set the tub on patio stones, bricks or concrete blocks if the legs are missing to allow the water to drain freely out of the drain hole.
Pour 2 inches of coarse gravel into the tub. Fill the tub to within 2 to 4 inches from the top with soil. Mix ordinary garden soil with sphagnum peat moss, soil-based potting soil and rinsed coarse sand in equal parts or purchase fast-draining soil-based potting mix. Do not use peat-based potting soil or unamended garden soil.
Test the soil mix to determine the pH. Add lime to raise the pH or iron sulfate to lower it to between 6 and 6.5, if necessary. The amount of lime or iron sulfate required will be based on how far the pH must be adjusted.
Pour water over the soil and mix it until it is uniformly moist. Plant dwarf, compact or bush vegetable varieties. Space them far enough apart for them to reach their mature width. Spread a 2-inch layer of organic mulch over the soil around the plants to retain moisture.
Check the soil every morning. Water the plants with 2 to 3 gallons of water when the top of the soil begins to dry. Fertilize the plants with water-soluble vegetable plant fertilizer every two to three weeks. Add 1 teaspoon of fertilizer to 1 gallon of water and pour it on the soil around the plants immediately after watering them. Do not splash the fertilizer on the plants.