I sort of poked around and experimented to figure this one out. There is no real racket science here but it is important to have a large enough bucket for the amount of plants you want to grow. I grow two to three plants per 5 gallon bucket. That gives me plenty of tomatoes during the season.
So you need to get a 5 gallon bucket with lid and wire handle. If the bucket doesn’t have a wire handle you can make one by taking heavy coat hanger and bending it to fit in holes you drill toward the top or the bucket.
Then you need two or three plants that are 10-12 inches tall. I choose indeterminate types that vine as there hang better but you can use just about any kind.
In the lid, drill 4-5 1 inch holes (this is for water drainage). Drill a few holes in the bottom of the bucket for drainage, too. And finally using a 4 inch hole saw, cut 2 to 3 holes in the sides about halfway up the bucket. This is where the plants will grow from.
With a good quality potting soil, fill your bucket up to the bottom edges of the holes in the sides. If you are concerned about the soil washing out, you might want to add an inch or two of drain rock or wood chips to help.
Now, after taking the plants out of their pots, lay them sideways on the soil in the bucket allowing the plant to stick out all but the root ball.
Finally, fill the bucket to the top with more soil and water well. Place the lid on and perhaps weight it down with a rock to keep from blowing away in the wind. Ask me how I know!
It’s going to be heavy so hang this from a sturdy bracket from your eaves or a post.
At first, the plants will grow upward toward the sun which is natural. It is really only later that they begin to grow downward from the weight of the fruit.
You will want to water your “upside” down tomatoes more often than their garden grown counterparts as they evaporate more quickly. At least once a day and sometimes twice on hot days.
And there you have it. Try this at least once for fun and you might find yourself upside down with peppers, too.