There are two approaches for planting an upside down tomato. Planting it right side up and letting it grow for awhile before hanging it up, and planting it upside down from the start. The advantage to planting right side up is that it gives your tomato a head start. The disadvantage is that your upside down tomato planter will be much heavier because you have to fill the bucket completely with soil.
Right Side Up Start
Some people like to plant the tomato right side up to start with and let it grow like this until the plant reaches around 12 inches, before they hang it. The advantage to this is that the container won’t shade the tomato plant when the sun is overhead. Also, upside down tomatoes try to grow up - it's just what plants do - even if they are upside down, so by starting it right side up, the plant won't contort so quickly. However, to plant this way, you have to fill your bucket to the very top, with soil, which makes it super heavy.To use the right side up planting method: Fill your bucket with potting soil right to the top. Put the lid securely on and then turn the bucket over (so the hole is on top now). You then push your tomato plant down into the soil. Tomatoes are one of the few plants that you want to plant very deeply, because roots will grow from the stem. So plant it up to the first set of sturdy leaves.
To plant your tomato upside down: Fill your bucket with potting soil, but not to the top. The soil level can be 3 to five inches from the top of the bucket.
Put the top of the bucket on securely, and tip bucket onto its side. This is really a two-person job. Stuff the tomato seedling deeply into the hole, up to its first set of sturdy leaves. You are pushing it through the screening flaps, which will bend back. Once the tomato is in, you’ll want to pull the flaps out so that they lay flat on the soil.
