Do-it-Yourself Upside-Down Planters

Grumpy's Castle; 26 July 2010 --

A while ago, Grumpy said that he would describe his design for a do-it-yourself upside-down planter. This post will be an attempt to do that, using easily obtained recycled materials. The reader may use his own imagination and ingenuity to modify the design to suit the materials he/she has available.

Main items needed:

Here are the primary pieces that are required: A five-gallon bucket & lid, preferably black so the heat of the sun can keep the roots warm; a sturdy plastic 4" planter pot, preferably having a rolled top; a 3/4" thick piece of porous, fairly rigid plastic foam.

Tools required: A compass with which to scribe a circle to guide cutting a round hole in the bottom of the five-gallon bucket; A sharp knife or Xacto knife with which to cut said round hole and also to cut a 1 1/4" hole in the bottom of the 4" planter pot as well as to trim the piece of porous plastic foam to fit snugly in the bottom of the 4" planter pot. A slit should be made to the approximate middle of the foam disk. If Grumpy could figure out how to reliably cut a hole in the bottom of a terracotta pot, that would be his ideal!

I prefer the plastic planter pots which have a rigid rounded rim (e.g. 4" 'Shuttle Pot', #SP433); this rim will support the weight of the tomato plant without being deformed and pulled through the 4" hole in the bottom of the five-gallon bucket.

I also have white five-gallon buckets; I plan to spray paint them with flat-black paint (the type that will adhere well to the polypropylene plastic of which the bucket is made). Other dark colors would work OK, just not quite as good as black however.

I anticipate that cutting the hole in the bottom of the bucket may be the most difficult job; the plastic buckets are fairly thick and it may be slow work to cut through the plastic as well as keeping the hole very closely round. If you have a sabre saw or Dremel tool that can cut on a 4" diameter  circle, that might be easier. At any rate, if you use a knife (as I probably will) or an Exacto knife, be careful not to slip and cut your fingers. Grumpy probably will ignore this precaution!

4" pot, with hole cut in bottom

The 1 1/4" hole in the bottom of the 4" pot need not be as precise; it is important to leave enough bottom material that will support the 3/4" thick porous plastic foam. The minimum size of this hole needs to accommodate your tomato seedling at the time you decide to replant it to the upside-down planter. It is important that this hole have no sharp corners or "nicks" in it; these imperfections will greatly weaken the ability of the remaining material to withstand the weight of the tomato plant as it grows to maturity. Think about how heavy your tomato plant will be by mid July and early August when it is loaded with luscious tomatoes -- the foam must not rupture the pot bottom and slip through the bottom of the 4" pot!!

Depending on the hooks on which you plan to hang your upside-down planters, you may need to remove the handle-piece typical on a five-gallon bucket. Keep in mind, though, that without that add-on handle piece, the small diameter wire bail that is left will be painful to your hands when the planter is full of soil -- and even more so when it is adequately moistened! I  initially put in only enough soil to cover the roots on the seedling I have just inserted; after hanging the planter, I then pour in more soil (and organic vegetable fertilizer, in layers) as needed to fill the planter to within 3-4 inches from the top.

Finally, after your planter is hung and filled with soil, the top should be placed over the opening. This is to prevent loss of moisture due to evaporation. Before placing the top on the bucket, cut a hole about 1 1/2 to 2" in diameter near the center of the top; this is the hole into which you will provide irrigation for your upside-down plants. Grumpy's preferred method is to drill a 1/8" hole in the center of the plastic lid from a 3 liter Ocean Spray juice bottle, then poke (with a large needle) a 1-2 mm pin hole in the side of the 3 liter bottle between the handle and the neck. The distance between the 1/8" hole in the lid and the 1-2mm pin hole in the side provides approximately the right amount of pressure difference, when the bottle is full of water and turned upside down into the hole in the 5-gallon lid, to provide about 1-2 drops of water per second. Ideally, 3 liters of water should last 2 days during the early season; during the hotter days of July and August, 3 liters per day may be advisable. If the 3 liter bottle is allowed to lean at approximately a 45 degree angle, the rate of drops can be adjusted by turning the 3 liter bottle slightly to the left or right (decreasing the vertical distance between the hole in the lid and the hole in the side).