- 4 identical, used, full-sized automobile or light truck tires (preferably at least 30 inches in diameter)
- 3 joints of top chain-link rail fence tubing (1.375-inch by 10-feet)
- 1 welded-wire livestock panel (4-feet by 16-feet with 4-inch mesh) OR
- 1 sheet of plastic lattice (0.2-inch-by-4-feet-by-8-feet)
- 1 box (40 count) self-tapping sheet metal screws (no. 10 by 1-inch)
- 1 box tek screws (no. 12 by 3/4-inch)
- 6 machine bolts including nuts (5/16-by-6-inch)
- 18 pipe hangers (1-inch)
- Weed barrier fabric (4-feet-by-50-feet roll)
- Duct (Gorilla) tape
- 3 2-cubic-feet bags of potting soil
Designing Tower Base
Choose one tire to be the tower base.
Using a tape measure and a white marker, make six evenly spaced lines on the tire as shown.
Cut the top chain-link rail fence tubing into six, 60-inch long posts. Remove burs on the tubing.
Drill a 5/16-inch bolt hole, 10 inches from one end, in each post.
Install posts using 1-inch pipe straps and 1-inch self-tapping sheet metal screws. Use two straps per post. Before attaching post to tire, place a short piece of two-by-four lumber under the post.
Align the center of each post over the mark, and use a level to ensure the posts are plumb before attaching.
Insert bolts into holes at the end of each post, and secure using nuts. Make sure bolts on opposite posts are aligned with each other twisting posts as needed to align.
When posts are aligned, attach hangers to posts using ¾-inch tek screws.
Preparing Planter Modules
Create three planter modules by removing the side walls from the remaining tires. On one side of each tire, use a utility knife to remove the side wall as close to the tread as possible without exposing the steel belting. A jigsaw equipped with a fine-toothed hacksaw blade or rubber cutting blade can also be used for side wall removal. Save one of the side walls.
To prepare the opposite side of each tire (planter module), mark the side wall along the midpoint (crown). Cut along the line to remove the side wall. This section of side wall may be discarded.
Construct a bottom for each module using a piece of plastic lattice or metal livestock panel. Using the saved sidewall as a template, mark off three bottom sections using a permanent marker. Use a jigsaw to cut the lattice or a pair of bolt cutters to cut the metal panel.
Prepare a liner for each bottom using a piece of weed barrier fabric. Use binder clips to attach fabric to the outer edge of the bottom sections or gather the fabric on the back side and secure using Gorilla tape.
Installing Planter Modules
Insert one of the growing modules into the tower frame and position on top of the base.
Next, insert the fabric bottom.
Attach the planter module to the frame using pipe hangers and sheet metal screws. One pipe hanger per post is sufficient. To avoid injury, grind off protruding screw tips.
Move tower to a permanent, level location before adding growing medium.
Planter Module Configurations
- When filled with growing medium, each module provides about 8 inches of growing depth. This is sufficient for root crops, leafy greens, strawberry and bedding plants. For large, deep-rooted crops such as tomato, pepper and trellised crops, the modules can be stacked to create additional rooting space. In a stacked configuration, only the bottom module needs a bottom section.*
- A two-level set up is ideal for growing a combination of high-light-requiring crops and crops that can tolerate some shade. In this configuration, strawberry will thrive on the upper level while leafy greens and root crops may be grown successfully on both levels. The support bolts must be installed (along with a bottom section) to use the upper planter module.
- Water dripping onto the lower planter module can be expected when using the two-level configuration. This should not pose a problem when growing greens and root crops but may increase disease pressure on warm-season fruiting crops growing on the lower level. If this becomes an issue, remove the growing medium from the upper module and replace with containers. Be sure to install a plastic liner before positioning containers.
- The tower planter is easy to accessorize. Hoops fashioned from 1-inch diameter polyethylene tubing inserted into the ends of the posts will support a greenhouse covering fashioned from clear plastic sheeting.
- A cage trellis can be fashioned from a section of remesh concrete wire fastened to the posts using plastic-coated wire or zip ties.
Use soil mixes high in organic material, such as peat moss and composted pine bark, to reduce weight on the tower frame.
Steve Upson serves as a senior soils and crops consultant with horticulture as his expertise area. Upson specializes in raised bed and container gardening, vegetable plasticulture, and hoop house vegetable and small fruit production. He also provides consulting services to organizations interested in starting community and school gardens. Prior to joining the Noble Research Institute in 1988, Upson managed a commercial vegetable farm and served as an extension horticulture agent for Oklahoma State University.