Stressful Care of Limberlost Garden in High Duration Heat and a Pandemic

The Earth Arch with 75% weave of Aluminet on top, 50% weave below that, and high tunnel of hydrophobic row cover inside.

I built an arch shade house in March 2012 to help heat stressed squash survive fierce sunlight. That shade house got me thinking about the future of my garden. I could forecast problems already showing up under long-duration heat and drought. The arch shade structure seemed like it might be a good framework for experimenting with shade to control temperatures of the bed. I raised about $5000 in four rounds of crowdfunding using Kickstarter and Indiegogo platforms. I documented the creative process that produced ten arch variations that were part of a business development process using prototypes. Four of those prototypes were commissioned by supporters. The Earth Arch design took advantaged of insights gained from all of these experiments, as well as my own history with solar heated housing.

Summer of 2019 would put a different kind of stress on my forest garden and the Earth Arch (EA). It was time for Acacia and I to escape the summer heat. We planned a series of trips that would keep us out of the desert most of June, July and August. I employed a rotating triad of friends of friends to care for the food forest, the animals and the EA. The plants were dependent on hand watering, completed early in the morning. I was nervous about this plan, knowing much attention was needed. Its success was a roll of the dice.

The first week of June 2019 we got to see my granddaughter Hailey graduate high school in California. After that we flew to Seattle and got to spend two weeks with Bob and Donna of Rokalu farm on the Kitsap Peninsula. Bob and Donna host two young couples who lease land for organic gardens that feed the surrounding semi-rural population. Bob operates a thriving composting operation and drives a tractor that scares me half to death. It was great contrasting a small farm operation to my house garden.

The remainder of our 2019 July and August trip plans were upended by the health emergency of a family member. On our return to Tucson it was clear that our backups were not able to cover all that was needed. The garden made it through 3 weeks, but I had no solution for a several month absence. That experience led me to build a drip system that would lessen the stress of early morning waterings on housekeepers. Bob introduced me to hose-end water timers. I would bring that concept back to Tucson and spend a year implementing it, completing four zones in early July 2020. By March when the pandemic came along I completed two of four sectors of irrigation. Any plans for a summer get-away would soon be overwhelmed by the Covid-19 pandemic, and the one of the hottest summers on record. July 2020 was the hottest and 10th driest on record. On June 5, 2020 a lightning strike started the Bighorn Fire in the Catalina Mountains northwest of Tucson, Arizona on the Coronado National Forest. It would burn 119,978 acres, adding smoke and air quality concerns to the heat. It wouldn’t be 100% contained until July 23rd. This was followed my record all time heat in August, September and October. All told, 2020 was the 2nd warmest on record, setting a yearly record of 108 days of high temperatures 100˚ or hotter.

The Weavers Bamboo (Bambusa textilis) responded with robust growth to the switchfrom handwatering to drip irrigation

The Water Mystery

Hose-end water timers

Late in June in order to complete the drip irrigation I hired a contractor to install the third and fourth sectors of my hose end water timer system. It was completed July 2nd. When my water meter was read on August 5th, I was sent a bill for $742. The property typically uses about 25 to 30 CCF in July. This bill showed 60 CCF. We used an additional 30 CCF (One CCF = 748 gallons) which is 22,440 gallons. Keep in mind that I and the world around me were reeling from the stay at home orders due to the Covid-19 pandemic. Arizona was one of the states with the widest spread of the virus. I did my best to keep a distance from the workers, fearing for my own health. The result was that I had no real idea how many emitters were installed. My first impulse was to check the four toilets on the property. None showed any sign of leaking. My next impulse was to think the installation of the drip system was the problem. Yet I couldn’t see any evidence that a swimming pool’s worth of water was leaking, I was stumped. To make a long story short, after reading my meter and ruling out my household use and drip systems, I went back to a toilet in the separate studio building that had practically no use during the summer. This time I scrutinized the studio toilet carefully. Again there was no sign of it leaking when I flushed. I flushed it twice and the chain got hung up. I flushed it again after resetting the chain and the source of the leak was revealed. The handle did not return to the full down position, leaving the float valve hanging. That is how you lose 22, 440 gallons in a month – 748 gallons a day, 31 gallons an hour, half a gallon a minute, for 30 days.

Scott and Edna’s Arch Gets Restored

Scott looks at new gussets.

Scott and Edna’s Arch was completed in 2013. Scott and Edna love this garden structure. It sits on a steel plate over a culvert that diverts the monsoon streams of rainwater from above their house down a steep desert mountain hillside facing south. This location gets plenty of solar radiation as well as canyon whipped winds. A few years after construction they installed a mist system to help cool the interior. This structure used the original prototype arch design built with 2’x4″ lumber using exterior plywood gussets sealed with acrylic primer paint. The gussets sustained severe water damage from the mist system. In November and December 2020 I’ve replaced every plywood gusset with steel plate gussets and aluminum sheeting to cover the space where the plywood once was. Quarter inch concrete board lining the raised beds lacked a backing of plywood, and as the soil became wet and expanded, cracked the board in multiple places. The expansion also pushed side-walls outwards, forcing corners to spread. Fixing this damage involved placing new concrete board over the old, and waterproofing. This experience illustrates the value of learning from a prototype. I’d never built a raised bed structure out of 36″ high side walls before. Now that I’ve been back to repair the structure, I’ve learned alot about how it should be built.

The Writing Challenge

I finished my last commissioned arch for Rod and Carol in March 2017. The Earth Arch, which was started in December 2014, wasn’t completed until April 2018. The amount of finish work (sanding, sealing, priming, painting) for over 200 components was simply overwhelming. In the end it was an endeavor I couldn’t manage by myself. So I assessed the situation, knowing I was not going to risk taking on debt to grow Nurse Tree Arch as a business. I decided that the best way forward was to document the learning from the Nurse Tree Arch project, in writing – perhaps as a book. There is a good story here to be told about the challenge of home gardens under conditions of high-duration heat and drought. It is reasonable to ask the question: how will we continue to support gardens when the cost of water becomes 25% more expensive. Already the quality of potable water is problematic, due to chlorine disinfectant and high mineral contents. Given that I am using rainwater as much as is available, the record drought conditions means that I ran out of rainwater in June, and as of December when I write, I’ve got no more rainwater stored than I had in June.

In spite of tough conditions, the Nurse Tree Design project reveals that we can control heat and water loss through managed applications of shade, humidity containing row covers and fans moving the air. The research results are finding their way into writing. Stay tuned for more reporting of results on this blog site in 2021.