What should gardeners know about the idea of growing upside down tomatoes? While the practice is nationwide, there are some Colorado-specific concerns.
First off, plants know up from down. Auxins (hormones produced in the growing tips) turn stem growth upwards. When tomato plants are hung, new stem growth makes a U-turn upwards. In Colorado’s windy weather, the weight of the stems in windy weather can pull or break off the stem. The new growth will make another U-turn upward. A web search of online images of “upside down tomatoes” will readily show examples. Many on-line comments about hanging tomatoes talk about wind damage. Upside down planters can weigh 50 pounds when they are filled with damp soil and a large tomato plant. This creates a challenge to make sure all of the hardware is strong enough to hold the weight.
Some advertisements for upside down tomatoes suggest that they be hung from a balcony or deck. Trees, roofed decks, and nearby houses cast shade and tomatoes need full sun for good fruit production. The planter itself can block the sun and shade the tomato when it is a young plant. Not every variety of tomato will thrive growing upside down. Cherry tomatoes and other small-fruited tomatoes are better suited for upside down growing.
Another concern is the size of the container (root size) to support a large tomato plant. One brand of hanging planters calls for two pounds of soil. This small rooting volume would not support a large tomato plant in our hot, windy climate. Only a small container size tomato variety would be suitable.
Buckets are preferred over the thinner breathable plastic planters which dried out so quickly that watering even once a day was not enough to prevent desiccated plants.
Upside down planters are an option if you can’t grow tomatoes right side up for reasons of space or sunlight. Otherwise it is easier to grow them right side up. When you grow tomatoes upside down, you don’t have to worry about cutworms or ground fungus. However, these are problems you don’t have to worry about with any tomato grown in a container garden.