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CCAT Earthship Wall

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The goal of our project was to build a retaining wall with a culinary herb garden for the Campus Center for Appropriate Technology (CCAT) on Humboldt State University. This design is intended to support the growth of annual and perennial plants on a steep incline by creating step-wise levels for them to grow and to collect water and nutrients.

The earthship building method is discussed at length here: Earthships

Recycled materials such as tires and wood are used with the clay found at the site to shape the swale garden.

Fig 1: Humble beginnings

Project Requirements

  • Finish top row of clay packed tires
  • Excavate behind tires to make a planting bed for culinary herbs
  • Make a redwood retaining wall to hold the hill up behind the bed
  • Bring in topsoil and amend it
  • Cover top row of tires with gravel to make a walkway


Our design includes three layers of reclaimed tires packed with clay and gravel. In the middle layer annuals will be planted to hang down over the first stack of tires. The plants to be eaten will be grown on the soil (with manure, bat guano, and green sand) on the top. Gravel covers the top and bottom tire layers for aesthetics and walking/planting substrate. Donated Redwood constitutes the wall for the top planting area. The wood is held in place by bolts and wire. A rain barrel collects water at the end of the wall to be used for drainage and irrigation.

Donated Redwood used for support
Who's that fool?
Our whole class came out to help
Every swing counts...
Magic dust aka Bat guano
one two three
A drain and catchment system


  • The tires were free from Les Schwab Tires in McKinleyville.
  • The redwood was free (on the side of the road). A nice man chopped it up with his chainsaw for free.
  • We had to buy the soil and amendments. I purchased these at Mad River Gardens and they delivered the top soil. I don't know how much it cost because I gave the receipts to CCAT for reimbursment.
  • We also had to buy the metal cable, screws and washers to wire. These were purchased at ACE in McKinleyville. Again I don't know the cost because CCAT has the receipt.
  • The Gravel cam from Eureka Ready-Mix on Bode Rd. It was $20 for all I could take in my truck.

Tools Needed

  • Shovels - For digging and moving stuff
  • Wheelbarrows - for easy transport
  • pick axes - to break into the hard clay soil
  • sledge hammers - for packing tires
  • Screw gun - for screws holding wire to redwood
  • Hoes - for mixing in soil amendments
  • Strong backs for all the hard work


Though we did not get to the actual planting, we are proud to present a mighty fine start to a culinary herb garden for CCAT. The wall is solid and ready to go!

Next Steps

Plant perennials or wait till spring to plant annual and perennials. If we wait till spring (left for a future group) we will need to cover the soil to prevent the nutrients we added from leaching out with the coming rains.

Also in the future: A second swale above the redwood wall with fruit trees.


Earthen construction is hard work!


Contact details

The group consists of:

Dan Hughes,Stephani Pescitelli, Thallia Bird, Krystal Ocean, & Jamila Ghoul

Special Thanks:

  • Azad, our awesome contact at CCAT
  • Richard Hansis, HSU Professor who gave us the redwood
  • And especially...Special thanks to the rest of the class who donated three hours on a Friday to help us conquer that clay wall. You guys rock.
  • Also, thank you to other Friday volunteers such as Karly.

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