Garden Experiments Archives

Experiments in the Demonstration Garden: Potato Towers

Posted on December 5, 2017 by sara

This blog is the third of a three-part series.

Garden Intern Clara and Demonstration Garden Volunteer Theresa preparing to fill potato towers with soil and compost. Potato tower experiement, spring 2017.

Building from Blogs

After reading several gardening blogs which enthusiastically endorsed potato towers in spring but never followed up to share how the towers had performed post-harvest time, the staff of Gateway Greening decided to put this technique to the test. Our goal was to see if potato towers are an effective method of vertically growing sweet potatoes as a way to maximize growing space in the home or community garden.

Limited Resources, Limited Testing

Although our staff originally planned to test this method using three towers of various heights and widths, we scaled the experiment back to create just one tower due to soil availability. (At the end of the day, expanding school and community gardens comes first. Experiments in the Demonstration Garden come second.)

The potato tower we constructed is close to six feet tall. Built around an irrigation tube (PVC pipe with holes drilled into it) and lined with burlap, Demonstration Garden intern Clara and volunteer Theresa filled the tower with thin, alternating layers of topsoil and compost. Next, small holes were cut into the sides of the tower at regular intervals for sweet potato slips to be tucked in.

Over the course of the summer, volunteers and staff carefully watered the tower by spraying down the burlap sides and also by using a hose to run water through the irrigation tube. Little by little, the slips began to flush out into vines and flourish.

Did it Work?

Although several sweet potatoes were harvested from the tower this fall, Garden Program Manager Dean Gunderson has decided to repeat this experiment again next summer. Technically the experiment was a success – but there was definite room for improvement.

Volunteers from Nike, and Eco Constructors helped to harvest sweet potatoes from our experimental growing towers. The harvest may only have been 30 pounds, but it was certainly fun!

When we constructed our potato towers, we made a fundamental mistake: we planted the tower with sweet potato slips shortly after it was constructed. Throughout the summer the layers of soil and compost settled significantly, damaging the delicate sweet potato slips and their root structures.

As a result, we harvested few sweet potatoes and they seemed to be quite small, as though stunted early on. Our volunteers also observed that all of slips planted in the lower half of the tower died, and suggested that the sheer weight of the soil above prevented the potatoes from establishing below.

Potato Tower Experiment Planning for 2018

In 2018, Demonstration Garden staff and volunteers will be repeating the potato tower experiment with the original (now settled) tower and a second tower that will be shorter in size for comparison. Keep an eye out for photos and updates next spring!

To learn more about experiments that happened in the Demonstration Garden in 2017, please check out our Garden Soxx Experiment and 45 Degree Angle Trellis Experiment blogs.

Experiments in the Demonstration Garden: 45 Degree Trellis

Posted on December 5, 2017 by sara

This is blog two of a three-part series.

March in the Demonstration Garden. The 45-degree angle trellis was built over an existing raised bed, seen here full of winter cover crops.

One of the challenges of growing food in an urban environment is not only finding a space to start a garden, but also clean soil to grow food in. As a result, Gateway Greening is always looking for new ways to make the most of our available space.

Growing Up

Last summer, Garden Program Manager Dean Gunderson decided to tackle the 45-degree angle trellis. The concept is fairly simple. Instead of using a shade cloth to cover and protect vulnerable cool season crops, he would build a trellis and grow a vining plant across it. If it worked, the cool season crops would be protected by the leaves of the vine above, and would result in twice the harvest amount from the one growing space.

To start, Dean and long-time volunteer John Newman teamed up to design and build the trellis using spare lumber and cattle panel.

“The hardest part [of building the trellis] was figuring out how to stabilize the flexible cattle panel and how to attach the legs to it since it was narrower than our wide [garden] beds.” – Dean Gunderson, Garden Program Manager.

In the end, Dean and John built a wooden frame to support a single length of cattle panel and attached wooden legs to the sides for support. By varying the lengths of the wooden legs, they were able to create the desired 45-degree angle.

Planting for Harvest & Feedback

In the spring cabbage, broccoli, and other cool season crops were planted in the raised bed below the trellis. These are crops that often die off as summer arrives, and would be effective indicators of how well the experiment worked. A few weeks later, volunteers planted four tromboncino squash plants at the low end of the trellis to be the “shade vine.”

This experiment was particularly fun to watch. Unfortunately, the squash’s growth did not take off until summer heat hit, meaning it was not able to provide significant protection for the spring cool season crops. However, once the heat hit the tromboncino squash plants grew at staggering speeds, creating a shady nook in no time. More than one Saturday volunteer and staff member observed that it was a perfect place for a yoga mat and a nap!

Tromboncino squash taking over the 45-degree angle trellis in August of 2017.

Although it did not provide adequate cover in spring, the squash was more than able to provide cover for fall cool season crops. As a result, volunteers were able to plant carrots, cabbage, and a few other fall crops earlier than we typically would. The harvest from these crops was smaller than anticipated, but we suspect that was due to a lack of sunlight – the tromboncino squash vines really took off!

Our Recommendation:

Using vining plants in place of shade cloths can be an effective method of maximizing space while still protecting cool season crops, however, it does require extra management. Choose vining plants that will grow and provide shade at the time you need it most. For some of the more aggressive growers, make time to prune away excess vines to permit adequate sunlight to reach crops below.

Fun fact: Saturday volunteers harvested 263.45 pounds of tromboncino squash from the trellis experiment this summer. That’s 263.45 pounds harvest in just three months!

To learn more about experiments that happened in the Demonstration Garden in 2017, please check out our Garden Soxx Experiment and Potato Tower Experiment blogs.

Experiments in the Demonstration Garden: Garden Soxx

Posted on December 5, 2017 by sara

This blog is part of a three-part series.

Joe Maddox of Eco Constructors and local artist Steve Ingraham spent a morning helping to set up our two of our 2017 experiments: Garden Soxx and Potato Towers.

“I wish I could garden at home but…”

One of the most common phrases I hear from volunteers helping in the Demonstration Garden on Saturdays is: “I wish I could garden at home, but I live in an apartment.” On the other hand, we have several older individuals who tell us they “miss gardening but I just can’t bend over to pull weeds anymore.”

At Gateway Greening, we believe that gardening should be accessible to everyone so when an opportunity to test a new container gardening product came up, we took it!

Beginning the Garden Soxx Experiment

Thanks to a donation by Eco Constructors, a local business that specializes in sustainable, low-impact erosion control products, Gateway Greening received several Garden Soxx to test. These short tubes are made using a special mesh filled with organic growing medium from St. Louis Composting, and weigh about 30 pounds each when dry. Our goal was to see if Garden Soxx could be an effective method for container gardening in urban spaces.

Pole beans sprouting during the Garden Soxx Experiment at the Demonstration Garden in Summer of 2017.

For our Garden Soxx experiment, we placed several tubes along the edge of a brick patio in the Demonstration Garden. By doing so, we hoped to create conditions similar to an apartment balcony or concrete patio. One placed, staff and volunteers planted a small variety of crops commonly found in both home and community gardens: chives, purple basil, three different varieties of hot peppers, pole beans, and radishes.

Planting was a breeze. Using a small pocket knife, we made holes in the mesh fabric that were just big enough for our seeds and seedlings to fit inside. For the seedlings, we scooped out a small amount of growing medium to make space for the root systems. The extra medium was gently packed around and over the seedling’s roots to stabilize and protect the plant while it got established.

Throughout the summer volunteers and staff vigilantly watered the plants several times a week using a garden hose or watering can. Thanks to the mesh tube, we saw very little soil run-off and overwatering was impossible. Excess water simply ran out!

Before long, we started harvesting a small amount of produce from the chives, basil, and each of the hot pepper plants. Unfortunately, the resident rabbits made a feast of our pole beans shortly after germination, and our fall crop of radishes did not germinate – likely due to dry conditions.

A mix of basil, hot pepper varieties, and poles beans in Garden Soxx on the Demonstration Garden Patio in Spring of 2017.

Did it Work?

Overall, the Garden Soxx were an effective method for container gardening in an urban space, but they did present a few challenges as the season wore on.

Firstly, that the Garden Soxx needed almost constant watering during dry spells and the height of summer heat. With their sunny location and lack of wind protection on the edge of the patio, the Garden Soxx were prone to drying out quickly which stressed the plants. The second challenge was that the Garden Soxx needed a few applications of organic fertilizer throughout the summer to support ongoing food production.

Our Recommendation:

Garden Soxx would be ideal for someone looking to grow annual vegetables or flowers with shallow root systems on a balcony or raised patio. Gardeners using Garden Soxx should be prepared to water regularly, and add small amounts of fertilizer as needed. Want to check out Garden Soxx first hand? Stop by the Carriage House during the growing season in 2018!

To learn more about experiments that happened in the Demonstration Garden in 2017, please check out our 45 Degree Angle Trellis Experiment and Potato Tower Experiment blogs.