Monday, March 28, 2011

Edible Forest Gardens: Vol 1. Chapter 3 -- The Five Elements of Forest Gardens

I've been reading my way through Edible Forest Gardens (EFG) and just finished Chapter 3 of Volume 1 -- The Five Elements of Forest Architecture. What are these five elements, you may ask? They are:
  • Vegetation layers: the vertical structure of the forest
  • Soil horizons: Organic, Assimilation, Eluviation, Banking, Chemical, Durable
  • Vegetation density: much like our sense of "personal space" plants have preferences
  • Patterning: the forces of edge effects and surface area effects
  • Diversity: an attempt to bring more nuance to the discussion of species diversity
Interestingly vegetation layers came up in a different context this week when I went to the orientation for volunteers for the Backyard Habitat Certification Program where they talk in terms of 5 vegetation layers: tall and low trees, tall and low shrubs, and the herbaceous layer. In EFG they add to this list ground covers, and vines. They also introduce relative layers for the overstory, canopy, understory and root zone.

The soil horizons was largely review from the soils class I took last quarter at PCC. Yet it is always good to recall that half the plants and most of the life forms are living in the soil. The Organic or O horizon is often above what we usually think as the soil and includes the leaf litter and other organic mater in various stages of decomposition. Eventually hard working soil organisms incorporate this material into the lower horizon. The Assimilation or A horizon is the topsoil where most of the action happens: root growth, soil life, incorporation of organic matter, etc. Some soils have a distinct Eluviation or E horizon, some don't. This horizon accumulates clays that are carried by water (illuviated) from the A horizon and are deposited (eluviated) in the E horizon, it is usually light colored. The Banking or B horizon is often called the subsoil and tends to have less organic mater. A good way to develop organic matter in this horizon is by planting deeply rooted plants so that as the roots die back they leave organic matter in addition to the decaying soil life from the rhizosphere. They also help improve the soil structure and provide channels for good drainage and while alive a mechanism for pulling up nutrients into higher soil horizons. The Chemical or C horizon is where most of the soil formation activity happens chemically. Finally the Durable or R horizon is where it all got started with the parent material.

The section on vegetation density addressed the issues of vegetative cover and crowding. I found this to be interesting and instructive. Depending on the ecosystem that a plant targets as its niche it may have quite different preferences or tolerances to crowding, contention for root space, shading, etc. It also interacts with the choice of reproductive and dispersal strategies. This will be an important design consideration for me as it will be very tempting to crowd too many plants into too small a space. So the balance is between plant selection to accommodate this density and proper design to provide the plants the space they need to do their thing. At the Backyard Habitat orientation I saw a survey map of the greater columbian region from 1851 where my neighborhood was classified as "woodland" so probably 40-70% tree cover. It might then be reasonable to shoot for that same range in my design.

The patterning section was almost a tease -- the mathematical implications are intoxicating. The author investigated both the forces at play that lead to different sorts of patterns as well as the inferences we can draw to use as tools to weed less (less edges), or maintain easier access (more edges).

The text made the point that many discussions of diversity seem to treat it as an end unto itself rather than a factor to consider in ecological systems. Diversity can also take many forms beyond the simple count of species.

A couple misc. notes:
  • Nitrogen fixers need full sun to work.
  • Ribes (currants and gooseberries) fruit in shade.

Monday, March 21, 2011

Introducing the University of Here

I have been enjoying taking classes again. That said, I find that there are many things I wish to focus on that are not being covered. This has lead me to start a program of self-study that I am calling the University of Here at Campus Vorax. The basic recipe is:
  1. Pick a topic of study
  2. Identify texts or other relevant supporting material
  3. Identify learning objectives
  4. Identify evaluation criteria and learning "forcing functions"
  5. Write up a simple syllabus
I have written up four courses for the spring term:
My hope is that having a week-by-week schedule will provide enough impetus to make forward progress in the face of the myriad distractions which will present themselves.

Tuesday, March 8, 2011

Soil testing

In the soils class we have been using a soil test kit to test for nutrients in various soil samples.
Soil test kit
It has been neat to see what all goes into soil testing. Makes it a lot more tempting to just pay a lab....

Monday, March 7, 2011

Plant Propagation -- Week 10: Final observations

Last lab day of propagation we did a "final" round of observations of the handiwork from the term.
It was nice to see the radishes sprout and be all perky. Interesting how distinctly red the hypocotyl is.
The root seems pretty long for a week old sprout. The sprout was very tasty with a spicy kick.
Dave had some with roots growing out the bottom of the six pack.
And here is the proud father.
Several other seeds had germinated and emerged: basil, some parsley, and some california poppy.
I was surprised to see fully opened flowers on one of my strawberry plants. They all were then summarily snipped to redirect their energy to root development. Silly strawberries!
I was pretty discouraged about the snake plant until I looked closely and found four distinct, if small, roots protruding. So, there is hope yet.
By contrast the dogwood was going great guns with both root and leaf development.
Here is Sarah checking in on her plants.
In the hoop house the main action was with the siberian iris, which seemed to be doing nicely. Everything else seemed pretty dormant.
We gathered a crew to clean up the pile of nursery pots.
Here is some of the team proud of a job well done.

Sunday, March 6, 2011

Plant Propagation -- Week 9: seeds and The Flat Filler

We started our seed lab by using the flat filler to put planting medium into flats of 8 6-packs...

The medium rides up a conveyer out of a large hopper.

It then drops down onto a spinning fan that disperses the medium into the cells of the flat.

On the way out, the flat runs under a leveling brush.

And you end up with a nice flat that just needs to be hydrated and planted.

I planted up a tray with veggies and herbs (radishes, basil, parsley), as well as a few more challenging items.

We had some cool Earth Pots to experiment with. I planted a couple rows of basil, parsley, California Poppies, and nasturtiums.

For small seeds, I sprinkled vermiculite over the top.

Plant Propagation -- Week 9 -- Log

Let's take a look at how things are doing...
still not a lot of action with the leaf cuttings.
The Cornus cuttings are leafing out. But the Thuja are still not showing any activity.
I took a peek and the Cornus are putting on roots.
There is one cute little flower or fruit on the strawberry. I should have plucked it to keep the energy focused on root development -- but it was too cute. The foliage is looking very happy.
The snake plant isn't really doing anything. No roots, at least at first glance. If you look really close you might convince yourself there are some adventitious root tips forming.
At least it hasn't rotted away as I feared it might a few weeks ago.

Plant Propagation -- Week 7 -- There's no avoiding the graft

This week reminded me of the scene from Apollo 13:
We've got to find a way to make this
fit into the hole for this
... using nothing but that.

David introduced us to the M111 Malus root stock.
And the Golden Delicious scion wood we would be grafting to it.

The main tool for the day was an as-sharp-as-you-could-get-it grafting knife. We practiced several grafts: cleft, whip & tongue, veneer, and saddle. First up the cleft graft, accommodating smaller scion wood.
A whip & tongue graft with a nice tight fit.
A veneer graft on the side of the stem.
And the trickiest to do by hand, the saddle graft.
Here are all four wrapped up in stretchy tape.
With the practice over, we worked directly on the root stock. Exposed surfaces were coated with grafting wax.
And off to the hoop house to wait for callus to form.

I hate waiting.

Plant Propagation -- Week 6 -- Labor of Division

He who can properly define and divide is to be considered a god.

Today's task was plant division.
We started by tackling a patch of Iris sibirica near Building 7.
A couple students working together with shovels would dig out a patch, break off most of the bulk soil, and place it on the garden cart.
When we were done, we planted back several smaller clumps to fill in the area.
That's a nice looking pile on the cart.
We brought out a variety of tools including rakes to smooth out the soil and rake away debris.
Some of the tools ended up a little the worse for wear.
After dividing them up some more, we potted them up into mostly 1-gallon pots and placed them in the hoop house.
Also on the menu was some Panicum virgatum 'Hans Hermes' and Hemerocallis (pictured).

After a lot of hard work it was good to feel that we succeeded in the mission: divide and conquer.