Tower Garden instructions indicate it’s best to place herbs and large plants in the bottom rows of the tower. After a year of tower gardening, we’ve learned the reasons behind this directive include what can happen both outside and inside the tower.
Blocked Water Flow: For example, the photo below shows how the root system from a Tuscany kale plant, grown at the top of the tower, wrapped around the inside blocking water flow to the plants below. But what you can’t see is how the roots extended down 4 levels!
The kale root system is small compared to what you see in the following photo. One tower gardener discovered just how aggressive mint can be when the roots of two plants completely blocked the flow of water within the tower. Another tower gardener had a similar experience with purple basil planted near the top of her tower.
We usually have mint growing in the bottom row but have learned to remove the plant once it reaches a certain size, regardless of it’s location. How can you tell it’s time to pull it out? Remove one of the plants in that row so you can see what’s happening inside the tower. When there’s a thickness of roots wrapping all the way around the inside, pull out the mint. Dry the plant for tea, plant it in a pot, or give it to family or friends.
A few weeks before that point, start more mint. Fortunately propagating mint is quite easy. Cut about a 3-inch piece off the top of the plant, remove all but the very top 4 leaves, place the stock in rock wool that has been soaking in water for 30 minutes, and transfer the rock wool to the tower.
Blocked Sunlight: Large plants growing at the top of the tower cause another problem…shade. Take a look at this huge brussel sprout and thriving parsley. Seedlings placed in lower net pots will struggle to receive the proper light, whereas reversal of the top and bottom plants in this tower would solve that problem.
Now you know two reasons behind planting the Tower Garden like a pyramid…smallest at the top and largest at the bottom. Remember, young plants can be moved around. If you think a plant might do better in a different location, don’t hesitate to change it.