Soil & Climate Change Mitigation

Author's comment: It's amazing how far I've come in understanding soil science since I first started asking questions in 2012. See blog posts here and here. At the time I was caretaking a couple garden spaces, and little did I know the soils were actually in decent shape (thanks to the efforts of former gardeners). Also six years ago I wasn't making the connection between soil building practices and climate change, nor was I aware of our rapidly depleting top soils. A few years later I was gardening in a newly tilled area with no soil building at all--a great demonstration of the effects of urban development on Seattle Soils. See that blog post here. Fortunately at the time I was in the middle of a "Soils" class so was able to interpret the results of the test. Still I wasn't thinking in terms of climate change mitigation; I'm not sure why but it seems hard to talk about it. In my current garden in West Seattle, I haven't actually taken any soil tests yet. Just by looking at the health of the plants and the color of the soil I am able to determine it's in pretty good form. Of course, soil testing would reveal the fascinating chemistry within it--but it's not the right time of year to yield the best results. So I'll wait for now. And keep building the soil. And researching.

I've been gardening in West Seattle for just over a year. There are some peculiarities about this space, including that it sits in a ravine at the base of High Point, so gets part sun much of the year, and is in a bit of a frost pocket. When I first moved in I noticed a lot of the soil was sandy, which surprised me due to Seattle Soil's reputation of being clay/acid. Which was a good reminder of how much variation exists in any area.  Based on what I learned in the "Soils" class I was aware of soil building practices I could do to remediate the sandy soil, so I focused on that immediately. A couple months ago, I was transplanting some materials and noticed what a year's worth of soil building had given my garden at Tim's. I was so excited I posted a photo on my Instagram:

This gave me a lot of encouragement that with thoughtful effort, I can influence the health of soil in whatever garden spaces I am working in. Almost two years ago I took a "Soils" class at a community college, which opened my eyes to soil structure, chemistry and the formation of tilth. I couldn't believe I had been gardening all those years without this basic knowledge. I've now been coming to learn how the health of plants really begins in the foundation of soil science. However since this field is always changing with new research, I've committed to continuing my education for life on this particular topic, while investigating the microclimates I am working in. In addition, there is the issue  of climate change and how it will influence soil science in the time to come.

Next month, I am moving again--onto a farm on the Olympia Peninsula, and I've been told by the farmers they are working with peat soils. I know very little about this type of soil so in preparation, I've decided to do some research. All I remembered from my "Soils" class was that peat is a carbon sink with a ton of organic matter and poor drainage. Upon learning there are peat soils at this particular farm, a question immediately arose in my mind: should we be digging up peat soils? In the face of climate change--shouldn't we be preserving peat lands wherever they exist? I will begin answering this question only as I start working on this farm, I'm sure.

Peat soils are called "Histosols" per their taxonomy. Here is a nice map of histosols in the U.S. created by the NRCS:

This map suggests to me that the Pacific Northwest is not a region where histosols are usually found. So if we have them in our area, they are probably in little pockets. Also from this map we can observe the percent of histosols in general is very small! According to Soil Society of America, histosols make up only 1% of the world's glacial-free land surface, which makes them very special. International Peatland Society says they make up 3%--but either way it's still a very small amount. IPS believes for the sake of mitigating climate change that peatlands must be properly managed to avoid increasing greenhouse gases (CO2, CH4, etc) and compaction (caused by changing hydrology patterns), while increasing carbon sequestration. I couldn't agree more! I am not sure how to pose this conversation with the farmers but perhaps I can casually bring it up sometime while working in the field.

There is a really nice article in Permaculture News that discusses peat soils (read here). I am not sure what percent of peat this farmland is where I will be working, but I'm assuming the farmers lean more in the direction of realizing their economic benefits--as we've had very little discussion of permaculture practices thus far. I do know they haven't formerly drained their land, so it's possible the percent of peat is not super high--otherwise they wouldn't be able to produce their vegetables (due to anaerobic conditions). And I must also acknowledge the farmers are simultaneously practicing some conservation to maintain natural habitat, particularly along the waterways, and the area for vegetable cultivation is only around an acre (not including pastured animals). I am definitely not trying to imply the farmers are disturbing their peat soils, just that it's possible some of their practices might benefit from shifting into more of a permaculture framework.

The Food and Agriculture Organization of the United Nations (FAO) recommends "paludiculture" practices, which work within the constraints of the peat microclimate. Without disturbing natural hydrology, you can cultivate crops more appropriate for that setting. The FAO also suggests various fodder crops, wood (trees that can tolerate high saturation) and food crops including aronia berry, lotus, cranberry, water chestnut and wild rice. From my perspective this particular bit of land  might provide a great educational opportunity for people in the area on peat soils and paludiculture. In fact the farmers might be able to work with a conservation district or WSU to conduct research, and they could provide workshops on permaculture and paludiculture--peatland restoration and cultivation--for the sake of climate change mitigation. We certainly could use more organizations in the area that are directly tackling issues on climate change. 

Permaculture for Tim!

Now that I have lived in Tim's home for about a year, I am trying to apply permaculture principles to a larger site design. I've had a chance to observe sun and wind patterns and feel a tiny bit more confident about what is possible for Tim's property. The easiest will be the front yard garden, which I will call Zone 1. In October 2016, we started gardening in the front yard - tilling up the lawn, laying down manure and straw, and clearing out blackberry roots (I wish I had a photo from "Before"!). Here is a photo from last winter:

Over  the past year I put in edibles & ornamental perennials (donated), annuals and one fig tree. There are power lines overhead most of the yard so I had to place it carefully. Also, I tried to choose plants according to Tim's taste, and always checked in beforehand. He gave me a lot of freedom. It's amazing how after a little soil building, and making do with many donated plants and seeds, the front yard became this:

So here is our starting point for thinking about a larger permaculture design for the property. While considering Tim's personality and likely maintenance habits and goals, it's important to honor all the human elements: the house/deck, fire pit, batting cage, mother-in-law apartment and power lines -- all Zone 0. Designing sensible access around all of these will be critical, and minimizing high maintenance areas means all cultivated areas in the front yard -including just outside the fence and a small street garden- will be Zone 1. Everything else will be Zone 2. Here is a rough map (based on Google Earth image):

In this map I tried to clearly mark all the human elements (Zone 0: purple) and pathways. I wanted to place all cultivated areas into Zone 1 (green) to keep them under the scope of ongoing maintenance. They need to be properly cared for before more can be introduced; the greatest challenge will be keeping invasive weeds under control in most of Zone 2 (white). For example the south facing fence line of Tim's property has a terrible English Ivy problem, and the north-west facing portions of Zone 2 have a Himalayan blackberry battle. Zone 2 also contains new plantings like elderberry, bay tree, western red cedar and limber pine that will need a little bit of maintenance and a watchful eye. Caring for Zone 2 is essentially invasive weed management so that new plantings will be okay.

Now just for fun, here is the map again, this time with sectors depicted (sectors are external energies that move through land and influence how things grow, like wind and sun). I was recently introduced to a neat resource that helps you calculate the angles of sun where you live. In my first year of living here I wasn't sure what to expect and thought I may be living in a part-sun valley, so I didn't grow many heat-loving plants. I eventually observed that a portion of the yard receives full sun. To be honest I'm still not sure how to interpret the sun angles in this map, except to notice that the sun covers more of an area in the summer. Depicted here are the angles of summer sun (red) and winter sun (blue). I also included a fire sector around the fire put, thinking that plants shouldn't be placed around there for the sake of bonfires. I wasn't sure how to depict wind, though. I also added lines depicting where power lines go (unfortunately they're all basically in the front yard).

Now, I want to discuss the Zone 1 elements more in depth - they are all within the front yard fence line and the first thing people see when they visit the home. (Note: there is a small street-level garden, which should really be placed in Zone 2 because of it's proximity to the house, however, since it is already cultivated I will consider it in Zone 1.)

Zone 1: raised bed of greens; berry border; Fig Tree Guild, herb border

Raised Bed O' Greens

Characteristics: accessible to kitchen and close to spigot, consumed daily, high value

Needs: Nutrition, water, sun, hygiene, pest/disease management

Products: daily food for humans and insects, soil stabilization, beauty, multiple levels for growing plants in symbiosis (particularly the kale along the fence line)

Comments: the kale along the fence is starting to get tall, so I sowed cover crop (white clover) underneath for overwintering, and next spring other greens can be sown underneath. In the densely planted square bed, if we get many cold nights we might lose some of them (the mustard is getting stressed) but there's a great chance it will overwinter and stabilize the soil. In the spring we can cut much of it down, add some top soil and grow something else from another family. Before it was greens it was garlic. I'll have to see what Tim would enjoy there. 

Berry Border

Characteristics: several kinds of berries: raspberries, goji berries, strawberries, blueberry; high value perennials, food for humans and animals, high shrub and groundcover, in full sun year round, must compete with invasive himalayan blackberry.

Needs: acidic soil, lots of sun and water for berry production, nutrition, weed management, pruning

Products: delicious berries, seasonal interest (flowers and fall color), long term value, soil stabilization

Comments: the plants are all still babies and have many weeds to compete with, which luckily are all herbacious. Hopefully their roots will establish over the fall/winter so they will push a lot of new growth in the spring. The soil is more sandy in this area of the yard and suffers from some erosion, so continuing to add good top soil will be important. It's a big mystery as to how they will look in their second year!

Fig Tree Guild (Ficus carica 'Olympian')

Characteristics: baby fig tree planted, and some of the guild members are already present, as the tree gets larger with each passing year more members will be able to be added in. My dream is to have the whole front yard be a Fig Tree Guild.

Needs: good soil, sun, water, companion plants, weed management, training/pruning (not yet)

Products: summer shade, mulch, beauty, food, and it will be the one and only tree in the yard!

Comments: although figs grow faster than many fruit trees, it will be awhile before the guild really takes shape. A wonderful exercise in patience and also dedication. If we can set up the right environment from the get go, hopefully it will make it through it's first winter and be healthy! Stay tuned as more of this story unfolds with passing time.

Herb Border

Characteristics: In full sun, faster draining soil then inside the fence line; mostly perennial herbs and flowers that are drought tolerant; pleasing to the senses for pollinators and visitors, the first thing people see when they arrive! 

Needs: Pruning/ plant separation, nutrition, occasional summer irrigation

Products: Beauty, medicines, good smells, culinary purposes, gifts for friends and family

This is the photo from last year when it was first installed. Now below you an see what it looks like a year later!

Comments: this is my favorite area of the garden. There are so many textures, colors and smells all coexisting together. I am excited to see how all the plants evolve together in time. Also, I am hoping with the installation of vines and as the plants mature, the fence line will be obscured. 

In conclusion, I want to share my intentions for Year 2 on Tim's property. First of all, I wish to get the invasive weeds under control, and second, to appropriately maintain all the cultivated areas, while especially developing The Fig Guild. I am also not very clear on how wind moves through the property so will need to pay more attention to that too. Once Zone 2 is cleaned up and cleared out I can start thinking about cultivating other areas. Also -- given that the Fig is considered a Mediterranean plant, and because I believe I spent too much time/resources this past summer watering the garden, it would be best to transition the entire property toward more Mediterranean plants with minimal summer irrigation needs. Stay tuned!