Tomatoes in containers have the same nutritional needs as those grown in the open garden. The trick to growing tomatoes in containers is to deliver nutrients with methods that are tailored to container plantings. In a traditional vegetable bed, compost is turned into the soil to provide plant nutrients and add compost to planting holes. With container planting, plants can get the same nutrients, if the method of application is altered to a container setting.
Mix equal amounts of peat moss, builder's sand and compost to create a nutrient-rich potting soil that is also high in humus, doesn't compact easily and allows good drainage.
Provide an application of compost tea or fish emulsion, immediately after transplanting to give seedlings a good start. Make compost tea by seeping one quart of compost wrapped in cloth, in a gallon of water for several days. Aerate by stirring to activate beneficial micro-organisms that will help nourish plants.
Apply compost tea or fish emulsion again in mid-summer, after plant is well established and in full blossom.
Apply a foliar spray of compost tea weekly, once tomato plants have fully blossomed.
Provide an extra application of compost tea once fruits appear.