When you grow tomatoes (Solanum lycopersicum) in a planter, you can enjoy fresh produce no matter where you live. Tomato seeds that are appropriate for containers are designed for reduced growth so you can be certain your plant will stay healthy without needing to transplant to a bigger planter before the growing season is over. The best time to plant tomatoes is in mid-March to early April depending on your USDA hardiness zone. With basic care you can begin to eat your own tomatoes by mid-July.
Choose a type of tomato that will do well growing in a container.Most types of tomatoes do very well in this growing environment. Big Boys and Beefsteaks are good choices. The seed package will indicate if your selection is appropriate for a planter.
Purchase a plastic pot that is a minimum of 12 inches deep and 12 inches wide. If the pot does not already have drainage holes, create a few. Without proper drainage, your tomatoes will die of root rot. Insert a screen of the same size and shape into the bottom of the pot to avoid your soil from washing away during watering.
Pour enough potting soil into your planter to leave 1/4 inch of space at the top. Do not use garden soil because it may have insects that can damage your plants. Stir in a slow-release fertilizer following the manufacturer's mixing and ratio instructions appropriate for the size of your container.
Place your tomato seeds on top of the soil and gently cover with a 1/4-inch layer of additional potting soil. Water carefully with a spray bottle to keep from washing the seeds out of position. Keep the planter in a warm location until the tomato plants sprout. After the plants are 8 inches tall, remove all but two of them to prevent overcrowding. Discard the weaker-looking plants and replant the others in an additional planter.
Put your planter in a location that receives full sun. Check the plants everyday to protect from insects and to make sure they have enough water. Depending on environmental conditions, your tomato plant will need approximately one gallon of water per week. In addition to regular watering, water your plant once a week with a water-soluble fertilizer.