Varieties of tomatoes that have existed since 1940 or earlier are referred to as heirloom tomatoes. These tomatoes have existed in the vegetable garden world without any genetic alterations or hybridization. Home gardeners who want to grow heirloom tomatoes in containers have nothing to fear. These tried-and-true tomatoes grow well in containers.
Wash the container with mild soap and warm water if it was used for anything else before planting. Swish white vinegar around in the interior of the container to kill any soil-borne bacteria or fungi that may lurk on the interior's surface if the container was used for another plant. Drill drainage holes in the container if it doesn't already have them.
Fill the container with a high-quality potting mix.
Create a hole in the center of the potting mix with a trowel or by hand. Make the hole deep enough to bury 80 percent of the plant.
Water the heirloom tomato plant when the top 2 to 3 inches of soil are dry to the touch. Do not let the soil dry out. Water the plant's soil carefully, wetting only the soil. Remove any lower leaves that get wet during watering. Remove any leaves that show signs of fungal infections (black spots or yellowing) to prevent spread of the disease.
Feed the tomatoes a fertilizer formulated for specifically for tomatoes. Follow the label instructions for dosage details.
Place a cage or stakes around the tomato plant before it reaches 1 foot in height to hold up new branches and developing fruit.