122. Permaculture Design: Water, Soil, Site Visits & AI

Permaculture Roundtable: Context, Water, Soil and Designing on the Ground

In this episode of The Permaculture Vine Podcast Cormac and Graham are joined by Michael Wardle of Saviour Soil Permaculture.

The conversation covered what each had been working on, permaculture design and site visits, the use of large language models, water management across different climates and soils, soil testing and contamination, weeds and ground preparation, and the practical work involved in consulting, designing and installing permaculture systems.

Who’s at the Table

Graham Towerton is based in Michigan, where he works with permaculture clients and manages his own seven-acre property. At the time of the conversation, he was carrying out spring installation work for customers, growing seedlings for client gardens, completing design work and continuing his engineering work.

Michael Wardle works across Southeast Queensland and northern New South Wales in Australia. He is a full-time permaculture consultant, designer and educator through Saviour Soil Permaculture and said he has been doing this professionally for about 13 years. He is currently based in Ipswich and travels from there for his work.

Spring Work in Michigan

Graham had just returned from his fourth day of spring installation work for customers in Michigan. With the weather moving beyond the expected final frost date, he had started planting some of the more frost-tender annuals.

He was also returning to gardens that had been established three or four years earlier. At one client property, perennial plants were already emerging, plants were flowering and strawberries were developing.

On his own seven-acre property, asparagus was emerging, raspberries were leafing out, strawberries were flowering and around 1,500 garlic plants were in the ground.

Graham had started seeds in January using trays under lights and on heating pads in his basement. This year, that had allowed him to take his own seedlings to customers rather than buying them from nurseries. He had ten customers in Michigan for ongoing work and expected to visit the remainder over the following weeks.

Current Work in Southeast Queensland

Michael had recently completed his 15th PDC as a student, this time with Robin Francis. He described this as part of his professional development and continuous learning.

After returning, he had been catching up with his existing client work. He was also restarting his own nursery after several local nurseries he had previously used for client plants had closed. He had begun propagating perennial plants, although he expected it would be around four months before they were ready.

Michael was also involved in a 12-month project with Permaculture Australia involving around 60 participants across Australia. Participants would record information including what they were growing, how much they were growing, pests, water use, tools and techniques, and expected yields across different climate zones.

Alongside this, he was involved in a three-year bioregional project. Work already underway included a local seed library, schools and free community workshops.

Large Language Models and Permaculture Work

The conversation moved into the use of large language models and the difference between accessing information digitally and observing what is actually happening on a site.

Michael discussed their limitations in research and education. He described PDC students who had attempted to use large language models to complete design work but found that the resulting designs could be disconnected from the landscape, climate and landform.

Graham had used large language models for specific engineering research tasks, including finding research papers that he could then investigate himself. He also tested them for permaculture design and plant selection.

When he asked for plants suitable for his Zone 6 climate in Michigan, he said the resulting list contained less than 10% of the plants he already knew could grow there.

Cormac also discussed remote design. From his own experience, he said his view had shifted from seeing the completed drawing as the final product towards working with the client and considering installation and the work taking place on the ground.

Remote Design and Site Visits

Graham discussed his experience completing remote designs and working with installers. In his current local work, an initial consultation may establish what a client wants to achieve, their budget and basic information about the property, but he now places greater emphasis on visiting the site.

Looking back at the designs where he had personally visited the property, he said those visits allowed him to see things he would not have identified remotely, including variations in soil that were not visible through soil databases.

Michael described a suburban project that demonstrated another part of this process.

The initial ideas included a herb garden at the front of the property for a client who was a naturopath. A soil test subsequently showed chromium 6 at a level Michael described as 3,000 times higher than safe limits.

The design had to change. Removing the contaminated soil would have been extremely expensive, and its position at the top of a hill also created concerns around disturbance and erosion. Instead, the area was planted with native plants and turned into habitat.

The conversation also covered maps and other digital information. Michael described arriving at sites with assumptions based on available data and then discarding those assumptions after observing conditions on the ground.

Water Across Different Climates

Water became a substantial part of the roundtable as Graham and Michael compared experiences from different locations.

Graham described living in Western Australia in an area receiving around six inches, or 150 millimetres, of annual rainfall, sometimes arriving in only three rainstorms. That required different approaches to rainfall and rainwater harvesting.

He now lives in Michigan, where annual rainfall is close to 1,000 millimetres, but he still stores rainwater. During his 14 years there, he had experienced periods of six to eight weeks with almost no rainfall.

He has around 10,000 litres of stored rainwater and uses it for activities including watering seed trays and newly planted trees. He also has a well but said it was primarily intended to supply the household rather than irrigation.

Michael discussed drought conditions in Australia, including a period when an area that normally received around 700 millimetres of rainfall dropped to around 250 millimetres.

The conversation then moved into the relationship between water and soil.

Michael described the heavy plastic clay at Robin Francis’s property. In those conditions, he said water management was not simply about trying to sink water into the soil but could involve moving it across the landscape and storing it elsewhere for later use.

He contrasted this with friable soils and sandy soils where water can drain quickly.

Graham’s Michigan property sits on very sandy soil. He had attempted to dig a pond but found that it would not hold water, and he was considering converting the excavation into a subterranean greenhouse.

His approach to the sandy soil includes applying six to ten inches of mulch to help hold water above the soil surface.

Soil Testing and Contamination

The chromium example led into a wider discussion about soil testing.

Michael said he encourages clients to organise soil testing because of the history that can be present within a property. He discussed several patterns associated with older Australian suburban properties, including lead paint around house drip lines, possible contamination beside roads and verges, chemicals previously used for termite control and the locations of former incinerators.

Graham also encourages soil testing before design work.

Sometimes the results show that the soil is better than its appearance suggests. In other cases, the results can change what is planted or how it is grown.

He gave the example of clients wanting blueberries where the soil pH was around 7.5 to 8. His own Michigan soil is sandy and alkaline, and he said he had been unable to lower the pH sufficiently for blueberries. As a result, his blueberries are grown in pots.

Dandelions, Thistles and Soil Disturbance

Cormac had been experimenting with dandelion microgreens, which led into a discussion about dandelions and other plants growing across their properties.

Graham described Canadian thistles on his seven acres. He had seen them grow strongly in areas where he had improved the soil with compost, manure and mulch.

He had also repeatedly observed Canadian thistles appearing after major soil disturbance. Dandelions, plantains and other broadleaf plants would then follow.

The discussion became more directly practical when Cormac explained that he was considering rotavating his front garden to remove the grass.

Graham said he had previously used a rotavator but had stopped because it brought weed seeds to the surface and disturbed the soil structure.

His current method is to cut the vegetation to ground level and then cover it with six to ten inches of wood chips or mulch. He said this had been about 95% successful at removing grass and most weeds on the sites where he had used it.

Cormac then added that his front garden is sloped and needs to be terraced. Because the soil would need to be moved to create the terraces, he said he would probably rotavate it, terrace it and then mulch it.

Listening to the Client

The discussion about Cormac’s slope moved into the conversations designers have with clients.

Michael described working with a client who initially talked about wanting a food forest. During their discussions, something the client said led him to question whether that description matched what they actually wanted.

He suggested something closer to a holistic orchard based on monastic traditions and showed the client examples. The client responded that this was what they wanted.

Michael described listening to clients as part of the design process, including recognising when what they are describing may differ from the terminology they initially use. Time, soil, water and budget were also mentioned as factors affecting what can be designed.

Work for the Coming Month

Michael had five new clients he expected to visit during the coming month. His initial visits are three-hour consultations that provide ideas and context before discussing a larger scope if the client wants to continue.

He was also continuing his bioregional project, working with existing clients and carrying out educational work.

Graham’s immediate work included finishing spring planting for his ten repeat customers, completing design work and writing reports from recent site consultations.

His engineering work was also moving into an agricultural study involving biochar produced from waste material containing chromium. The planned study would use soil testing and plant tissue analysis to examine what happened to the chromium when the biochar was placed into soil mixtures.

Cormac was working from his recently completed shed studio. On his own property, his immediate work included starting more lettuce, clearing beds and continuing work in the garden.

Closing

This episode of The Permaculture Vine Podcast brought Cormac Harkin, Graham Towerton and Michael Wardle together for a roundtable covering their current work in Northern Ireland, Michigan and Australia.

The conversation moved through spring planting and client work, large language models and remote design, site visits, water management, different soil conditions, soil testing and contamination, weeds and ground preparation, and the conversations involved in working with permaculture clients.

Get full access to Cormac Harkin at cormacharkin.substack.com/subscribe