To create a three-tiered pot tower for compact container plant growth, all you need is a few sturdy plant containers. Pot towers look beautiful when made of terra cotta, but because these pot towers can get quite heavy, you may want to use plastic pots that look like terra cotta instead.
Bottom tier. For the bottom tier, choose a short, stout terra cotta pot 18 inches in diameter. If you would like to make a larger tier, choose a wider bottom tier pot, but adjust the sizes of the middle and top tier pots.
Middle tier. For the second tier, choose two pots that measure a diameter of about 6 inches on their bases (one or both pots can be terra cotta – one can also be a leftover nursery pot). It is very important to measure the bottom because pots generally have a wider diameter on their tops, and then taper down to have a smaller base diameter. When the second tier is placed on top of the first tier, you will have 6 inches of planting space all around the outside of the bottom plant container.
Top Tier. For the top tier, choose two plant containers with a base diameter that will allow you at least 4 inches of planting space all around the second tier. For each tier, you can vary the height of the containers, having the bottom tier be more short and stout, with the top tier being a bit taller and thinner.
To put the pot tower together, place one of the middle tier pots (which could be an old nursery pot or a chipped pot you don’t want to use anymore) upside-down in the middle of the bottom tier’s pot. Fill the bottom tier with potting soil, and place the second tier pot on top of the other upside-down pot. Repeat this step with the top tier. Place one of the top tier pots upside down in the middle of the second tier pot, then fill the second tier pot with potting soil. Then put the top tier pot onto the upside-down plant container within the second tier.
Now you’re ready to plant. Use any plants that have roots that stay small and compact. You may want to plant the bottom tier with ivy plants or other plants that hang down over the pot. The top tier can have a taller plant, such as rosemary or a small bit of lavender. This type of planting will make the tower look like a planted fountain, with the tall top plants spilling over, down to the bottom ivy that trails off over the edge of the bottom tier.
Make sure to turn your pot (be careful) every few weeks so the sun is evenly distributed to all plants. If your balcony gets a lot of wind, or if you just want to play it safe, purchase some water-resistant glue or cementing agent that won’t harm your container plants. Carefully affix the upside-down pots to second- and third-tier pots resting on them.