Monday, March 7, 2011

Upside-Down Tomato Planters by Duane Davidson

My upside-down tomato vine in early October.
As I start plans for the coming gardening season it's time to evaluate several experiments from last year. Among them was a trial of one of the upside-down tomato planter.  Let me share my results. I'll begin with some overall findings and then fill in the details.

• I harvested several dozen small-medium size tomatoes from a tomato plant that grew hanging from the bottom of an "upside-down tomato planter." I picked them into late fall.

• There were no insect or disease problems except for a single instance of blossom-end rot.

• It was difficult to monitor moisture levels inside the container, but I made a daily check part of my morning chores.

• To avoid frost at the end of the season I moved the container to a sunny spot indoors where tomatoes continued to ripen on the living tomato vine.

I grow tomato plants from seed and usually plant them both in a small vegetable garden and a couple of 18-inch lightweight pots. Some years I've been able to extend the pots' growing season by rolling them into the garage on chilly nights in late September and even into October. I wondered if a hanging tomato planter might also be brought indoors when frost threatened.

I purchased a tomato planter with a water reservoir on the top. It was made of canvas stretched over a heavy wire frame with an "X" cut into the bottom for the tomato plant. The water reservoir was a solid plastic basin that held a gallon of water when filled. Water was supplied to the planting mix beneath via a synthetic fiber wick stretched across the bottom of the basin, where it was in contact with the planting mix, The two ends of the wick, which was an inch wide and about one-fourth inch thick, extended up the sides of the basin and folded over the top rim into the water. This seemed an unlikely way to water the tomato plant, but it worked.

I filled the container with moistened planting mix by laying it on its side and filling the lower half, then feeding the plant's stem and leaves through the slit, and finally filling the rest of the container up to where the water reservoir would rest. The planting mix was a typical garden center blend, to which I added an alfalfa-based slow-acting organic fertilizer. The tomato plant I had reserved for this planter was Siberian, described by the seed house as a dwarf sprawling determinate variety producing good strong-flavored 2-3" fruit 57-60 days from transplant.

I decided the best location for my container would be a southwest-facing corner, where it would have the best protection from wind. Unfortunately this spot is shaded during early morning hours, but becomes quite warm later in the day, a condition tomatoes enjoy. I suspended the container from the crossbar of a pergola-type structure.

A cluster of ripened tomatoes, including the one with blossom-end rot, caused by uneven moisture conditions.
The container came with a simple "moisture indicator" to be inserted through a small slit in the side of the container. It was to indicate when the planting mix dried out and the reservoir needed to be refilled. It stopped functioning after a couple weeks and I found I needed to feel for moisture around the tomato stem at the bottom of the container. I might have done better using the device I have for checking moisture in houseplant pots, but didn't think of it until later. I added the tomato vine to my regular morning rounds of checking and watering containers. One of the first tomato fruits to set on the vine developed blossom-end rot, an indicator of uneven watering. Fortunately, there were no more such victims.

I'm not sure the reservoir and wick system is the best way of watering in our dry climate. I found a way a way to cheat a little by pouring more water into the container than it could hold. What spilled over the rim of the container quickly soaked through to the bottom of the container and re-hydrated the plant before the wicking action got started.

When nighttime frost threatened I unhooked the container and moved it into a sun porch where I over-winter houseplants. I found it was extremely heavy and ruled out moving it indoors and out every day to take advantage of warm autumn days while protecting it from freezing nights. Instead I hung it on the side of a plant stand and let the tomato vine spread out on the floor. There were still a large number of green tomatoes on the plant. They ripened and I enjoyed eating home-grown tomatoes through most of November.

I had also planted the same tomato variety in my backyard, where its vines grew larger and produced tomatoes about one-third larger. The backyard plants received slightly more sun and more water; they also produced more cases of blossom-end rot. At the end of the season their unripened fruit had to be stripped from the vines and brought into the basement for ripening with substantial flavor loss.

Next year I may force the container plant with liquid fertilizer during the growing season and will try harder to get the watering right.