Experiments in the Demonstration Garden: 45 Degree Trellis

This is blog two of a three-part series.

45 Degree Trellis Experiment

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!


45 Degree Angle Trellis Experiment
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.