Growing tomatoes in planters is perfect for limited spaces or when garden areas are unsuitable due to poor soil or animals, such as deer, that may get into your plants. You can put planters on patios, apartment balconies or on a windowsill. Using determinate varieties of tomatoes work best in planters because they do not grow too large. Growing tomatoes in a planter will allow you to enjoy fresh vine-ripened tomatoes all summer.
Select a 5-gallon planter, preferably with drainage holes in the bottom. Use one 5-gallon planter per tomato plant. Add about 1 inch of coarse gravel to the bottom of the planter to improve drainage.
Fill the planter with potting soil and mix in compost to help with drainage. Dig a hole that is about 2 inches deeper than the height of the root ball and just as wide. Remove the bottom set of leaves and place the plant into the hole up to the next set of leaves on the stem. Planting tomatoes deeply allows for stronger root formation. Fill in with soil and firm over gently.
Water well after planting so the water runs out of the bottom drainage holes. Keep tomatoes watered sufficiently so the soil does not dry out, which can reduce the growth of the plant or cause it to die. Water once a day until the water runs out of the holes in the bottom.
Set the planter in a location where it will receive full sun all day. Some partial afternoon sun in hot climates is OK, but too much shade will cause leggy growth and less fruit.
Feed with a water-soluble liquid fertilizer lower in nitrogen, such as 10-15-15. The fertilizer should have nitrogen, phosphorus and potassium which are the three numbers, in that order, on the fertilizer container. Too much nitrogen causes lots of foliage growth and less fruit. Apply the fertilizer according to the manufacturer's directions every other week until tomatoes begins to appear, then stop fertilizing.
Place a tomato cage over the plant to provide support. As the tomato grows, work the stems through the cage to hold it up. You can also use a stake and twine.