Growing healthy food in Urban settings, a work in progress

1. Making Dirty Little Connections
Increasing Soil Health & Productivity
on a City Farm

2. a production from the
Tahoma Urban Agriculture Guild
written & presented by
Virginia Menstell, TUAG Director
“Improving soil health and productivity has nothing to do with the “silver bullet” approach of
conventional agriculture; dumping chemicals on the fields that feed us. Instead, it is about building
connectivity and diversity. In Urban Agriculture this is no more true. And as we better understand
how to belong to the land we live on, extraordinary change will occur. For all consumers in the
Urban Foodweb, including ourselves.” vm

3. An Introduction to Soil Health & Productivity
Three groups of Soil System members that generate similar outcomes in healthy soil :
➢ soil nitrification
➢ soil aggregation
➢ water storage
➢ disease suppression
Soil Microbes Worms Plants
By Shanegenziuk (Own work) [CC BY-SA 3.0
(http://creativecommons.org/licenses/by-sa/3.0)]
via Wikimedia Commons
By Doc. RNDr. Josef Reischig, CSc.
(Author's archive) [CC BY-SA 3.0
(http://creativecommons.org/licenses/by-sa/3.0)],
via Wikimedia Commons
By SuSanA Secretariat [CC BY 2.0
(http://creativecommons.org/licenses/by/2.0)]
via Wikimedia Commons

4. Group 1: Soil Microbes in the First 7 Inches
Soil Nitrification
➢ a build up & storage of water soluble
soil nutrients
➢ occurs as a process of cycling,
mineralization & immobilization
“ The conversion of ammonia to nitrate is
performed primarily by soil-living bacteria
and other nitrifying bacteria.”
from Wiki

5. Soil Microbes in the First 7 Inches
Soil Aggregation
➢ water absorption and storage
➢ the degree of aggregation indicates
the degree of soil microbial activity Microbial activity releases bacterial
polysaccharides or ‘soil gum’
which acts like glue, bonding soil bits
together. See here
from US Dept of Energy

6. A Comparison of Two Soil’s Aggregation:
a tool for improving soil health & productivity
Undisturbed grassland has a
relatively high amount of microbes.
see Soil Biology Primer
Good news!
Most of us have some undisturbed
lawn. If is also lacking chemical
herbicides & fertilizers we can likely
use some as a measure of good
soil aggregation. Try performing a comparison
between the aggregation beneath lawn to
that in your bedding areas.

7. A Yardstick for Monitoring
Here is how we did it in our yard:
Step 1
Dug up a chunk of lawn, about 7”
Step 2
Dug up a chunk of bedding area of similar size
Step 3
Compared the two using the soil aggregates
in the lawn clump as a model
Step 4
Rated the bedding area sample compared to the
lawn’s, used a scale of 0 -5.

8. Group 2: A (mixed) Bag of Worms
Epigeic - the surface food processors, living in or
near surface litter and common to compost piles.
Endogeic - act as root zone spreaders, feeding, moving about in
the upper layer of soils, creating small temporary channels which
become filled with castings.
Anecic - the soil miners create permanent vertical tunnels,
wider and as much as several meters long. Feeding habits deposit
castings at the mouth of burrow, along the walls of the tunnel.

9. Doing a Worm Survey
Here is how we did it in our yard:
Step 1
Clear of the mulch as needed and check
it for any surface feeding worms.
Step 2
Best done after a good rainfall, otherwise
after irrigating.
Step 3
Dig a cubic 1 foot out and place in a
wheelbarrow.
Step 4
Segregate the worms present by type
and log in a journal.
Step 5
Replace the chunks of soil to the
bedding area, then the worms &
top with mulch. leaf litter or straw.

10. Group 3: The Plants
Root Exudites - secretions which
feed microbes various types of
molecules; sugars, amino acids,
carbon & polysaccharides.
Plant Diversity = Exudite diversity = Microbial diversity = Disease suppression
Other Outcomes - soil aggregation (direct & indirect)
increase in soil nitrification (direct & indirect)
increase in water holding capacity (direct)
Crescent Berm: Comphrey, Mastic Thyme, Echinacea, Rosa
glauca, Hyssop, Calendula

11. Group 3: Plant Diversity = Root Exudite Diversity
Here is what a Plant’s Root Exudites look like:
from
Root exudates as indicators of
plant reaction to acid and nitrogen
inputs into forest ecosystems
See here

12. Getting Downright Dirty (or how to belong to a soil system)
What if we as Humans, could become functional soil system members?
How could this Happen?
What could be the Outcomes?

13. Means & Methods
Organic Waste as Feedstock
1) Determine what your soils &
crops need to consume to thrive.
2) Determine what your kitchen
scraps currently have to offer as feedstock.
3) Make adjustments accordingly:
change household consumption patterns
or products that better fulfill the dietary
needs of your crops & soils.

14. Means & Methods
Establish or Increase Plant Diversity
Consider:
➢ What are the gaps left between the needs
of the soil system and what our compost
feedstock now provides?
➢ What are my crops currently supplying
the soil? organic detritus, nitrogen, potassium,
trace minerals, etc
➢ What other plants might be added to
produce a desired return to the soil?
perennials, annuals, cover crops, etc

15. Means & Methods
Create a Dirty Little Connections Journal
Items to include:
➢ Date, Weather Conditions
➢ Comparative Soil Aggregation
Ratings: suggested scale, 0-5
➢ Worm count for all three types
➢ Crops Present or types of Mulch
➢ Notes or Observations which
document the feedback your garden
is giving you

16. A Short Recap
There are three groups of organisms in a growing space that produce similar and
important outcomes. Together the outcomes generate health and productivity for the
entire system.
Organisms:
Soil Microbes, Worms & Plants
Outcomes:
Soil Aggregation, Soil Nitrification,
Water Holding Capacity &
Disease Suppression
We can become functional members of the system and here
are some ways to begin:
➢ learn to manage and adapt our waste streams to serve
as suitable soil feedstocks
➢ perform regular soil aggregation evaluations
➢ do a seasonal Worm survey
➢ practice Urban Polyculture - grow a diversity of crops
➢ keep a Journal on what the garden is offering as
feedback

17. Best wishes for Making Dirty Little
Connections
Thanks for joining us!
Here’s some resources to get started:
Doing a worm survey
Composting & Kitchen Waste Stream Banana Peels Coffee Grounds
Cover Crop planting Perennial Crops
For additional resources on this presentation go to the Tahoma Urban Agriculture Guild blog