Large half-whiskey barrel planters supply a durable container for a larger food-producing plant such as a tomato (Solanum lycopersicum). These barrels often hold more than 20 gallons of soil, which supplies plenty of room for the tomato to send out a large and healthy root system. You can grow a single indeterminate tomato plant, which can grow five feet tall or more, or three or four smaller cherry tomatoes in a single barrel. Preparing the soil and planting the tomato correctly after spring frost danger has passed further ensures a healthy and productive barrel garden.
Set the empty whiskey barrel in a location that receives six hours or more of daily sunlight. Heavy barrels are difficult to move once filled. Drill a few drainage holes in the bottom, and line the bottom with a piece of fiberglass mesh to hold in the soil mixture.
Mix 1 cup dolomite lime and 1 cup 5-10-10 fertilizer into each 2.5 cubic feet of a soilless potting mixture. Fill the barrel to within 2 inches of the rim with the mix.
Dig a planting hole two inches deeper than the tomato's seedling pot. Situate the hole in the center of the pot for tall tomato varieties, or space the holes at an equal distance apart for small cherry tomatoes.
Lift the tomato out of its seedling container. Set it in the hole so the stem is buried to just beneath the bottom set of leaves. Tomatoes form roots off buried sections of their lower stem, so planting deeper results in a larger root system to support the plant.
Fill the hole in with soil and firm it gently around the base of the tomato. Water thoroughly until excess moisture begins to seep from the bottom of the barrel.
Insert a plant support immediately after planting. Push a stake into the soil until it touches the bottom of the planter, positioning it about 4 inches behind the tomato plants. Tie the main stem to the stake at 8-inch intervals as it grows. Alternatively, set a tomato cage over the top of the tomato immediately after planting.