Nottinghill Forest Garden – 2012: Consolidation & Diversification

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This is Part Three (A) of a series of Articles, that critically discuss’s the Nottinghill Forest Garden Project from Analysis – to Implementation – to Future Idea’s.

Part One can be found here.

Part Two can be found here.

2012: Consolidation & Diversification

2012 Goals

After a year full of very hard work establishing the system, it was time to begin to allowing nature to do the work for us. At first, the title of this section may seem a bit contradictory. How can you, at the same time, consolidate and diversify?

By consolidate, I mean to hold on to the gains that we made in the first year and reinforce them while concurrently reducing the amount of time and energy we would invest. The age old method
of cover cropping: hardy, multi functional species improving the soil and occupying the majority of the niches available would prove to be a valuable tool in this effort. I wanted to use the second year to increase biomass production on site and replenish the soil’s nitrogen. Expanding comfrey to widen our nutrient net was also a high priority (and is ever so easy to accomplish).

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Diversification would be mostly geared towards incorporating more natives into the garden. We focused on native perennial nitrogen fixers and specialist insectary species to continue improving
the quantity and quality of niches available in the garden. Very often native species provide more ecosystem services than introduced species.

Diversification would also be promoted through the use of a combined endo and ectomycorrhizal inoculant in hopes that our existing trees would receive some additional benefits from new species of fungi. Lastly, with the worm compost (vermicomposting) working quite well, regular soil drenches of aerated compost tea would boost soil life. Taken together, our efforts to diversify the structure and species composition of the garden would work hand in hand with our goal of consolidating the benefits that came with extreme site remediation in 2011.

While I was interested in assisting some plants to grow some food for us, I was mostly focused on giving back to the system and racing against the closure of the canopy. Observation was the name of the game in the second year with only a few tweaks around the edges to further optimize water harvesting or species composition in mind. Of course, by doing all of these things, we were
accelerating the speed at which the canopy would close!

The only place we would really focus on expanding the garden to was the north side of the larger pond- the greater portion of the southern facing berm with its excellent aspect and microclimate created by proximity to the pond. I started collecting sheet mulch material in later winter for this.

Perhaps the most important reason to consolidate and diversify was that I was set to emigrate to Finland in the summer of 2012 and I wanted to make sure that I was doing everything possible to transfer the garden over to the family in a state that would be much easier to maintain.

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Soil Development & Cover Cropping

Soil Sample Results

Continuing to emphasize healthy soil, we sent soil samples at the end of 2011 (12/12/2011) to the state lab in order to gauge the after effects of the site preparation techniques I had implemented. The report was completed on January 18th, 2012.

I have reproduced 2010’s Soil Sample Results on the opposite page underneath this years results to make comparisons easier. You will note that the names of the Soil IDs have changed, but I have kept the colors to match the general area. The names changed simply because with the amount of site preparation and one year of gardening, those same soil zones have had entirely new patterns imposed on them. We can still compare the results as they have changed quite dramatically. I’ll start by examining the southernmost and highest guild on the property and move north and down through the garden.

The green guild had no direct comparison since we did not take samples from this area in 2010. It is interesting to note that because we did not grow any “fruits” or other demanding vegetables
here, that the phosphorus index is the highest of all the samples, with the exception of the small garlic beds which had high quality topsoil added to them from the raised bed. Therefore that sample is an outlier. The pH has been raised to a little higher than optimal, but still within a good “garden soil” pH range. Of course, the pH of the soil has only been increased in the top 10-12” of soil (about 25cm). Below that first shovel scoop, the soil had simply been decompacted. Still, the green guild’s cation exchange (CEC) and humic matter percentage (HMA) are double any result from 2010 (besides the raised bed, which is again, soil that had been imported). It is very encouraging that in the short span of 10 months, the soil’s ability to capture and store nutrients and water has been greatly increased.

The nightshade guild’s results are also quite positive: CEC & HMA have been dramatically improved as well, with the pH sitting inside an optimal garden soil range and phosphorus levels (according to the index) increasing by 6x! This in direct comparison to the “Willow” and “Oak” samples from 2010. Calcium and potassium are also in a better position, while magnesium has stayed
roughly the same and manganese and sulfur have slightly declined. Magnesium levels are, according to the literature available for interpreting these results, below optimum. Whether we should specifically address this is going to be up for discussion when we get results back from 2014’s soil tests. Rather than target one or two specific nutrients, I will probably continue to recommend building soil through diverse organic matter inputs. We should pay close attention to whether or not the plants exhibit signs of deficiency.

Next, the four sisters guild results show that, once again, that the addition of leaf mould compost (with an organic soil conditioner mixed in) protected by wood chip mulch has already made
an impact on the top layer of our soil (see the CEC and HMA results). PH is well balanced, phosphorus levels are much better (remember that they were almost non existent!), and the other nutrients have also increased, but not by too much. Slow and steady.

The results from where some Garlic had been growing from 2010-2011 demonstrate very good results in line with the changes seen elsewhere. The Bramble Soil ID corresponds with the area behind
the fence where we transplanted raspberry crowns and amended the soil. The results are encouraging here as well, but since this lies in our permaculture Zone 4 and 5 edge, we will not be spending much time addressing soil here for a while.

Overall, I was very pleased with these results with particular attention being paid to how well the soil had responded to the addition of organic matter on top of the soil. Of course, there were plenty of roots digging deep (deliberately inoculated by mycorrhizal fungi to boot) into the decompacted and amended beds as well. Remember, that samples are taken with the mulch and visible compost layers removed to get at the mineral soil, rather than testing the amendments. These results run contrary to the commonly held belief that organic matter needs to be tilled into the soil itself. In just ten months, feeding from above can make verifiable changes in soil organic matter.

It was decided that we would wait two years before exercising our right to free (tax subsidized) soil testing because we were not going to be making very great changes to the system in 2012 or 2013. Better to give the soil some time to respond to the coming cover cropping, chop & drop, and mulching regimes. I am eager to see how the soil’s pH has changed and whether or not we will be seeing any discernible changes in macro or micro nutrient levels through these additions. The only additional fertilizer would be sparingly used with certain vegetables or transplants and as always, these would remain organic or mineral in nature so that we would feed slowly from above.

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Table 3-1 2011 Soil Sample Results. Note: In order to test the mineral layer of the soil, any pure organic matter on the top (the O horizon) is removed.

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Table 3-2 2010 Soil Sample Results reproduced with widened columns to visually match with those from 2011.

Winter Cover Cropping

The winter of 2011-2012 was exceptionally mild and our cover crops were able to grow throughout the entire period and even flower as early as the first week of February! Since our chosen cover crop species were well established by the new year, the first few months of 2012 were really as simple as “watching plants grow.”

Care was taken to observe the garden each day and keep an extensive photographic record of different patches for future comparison. Fish were active in the ice-free ponds throughout the winter
and frogs were even observed on the move during this period. I was continually amazed by the amount of activity in the garden during the winter months. Even our cold hardy winter food crops continued to grow and thrive, when usually without some protection they would go dormant at some point. By rolling with the season and attempting to extend the collection and utilization of solar energy through photosynthesis, we were able to create a haven for local wildlife that typical gardening styles would leave to their own devices.

Photograph 3-3 clearly demonstrates, once again, the disparity between conventional landscape management and one oriented by permaculture principles. The neighbor’s lawn is largely dormant
and almost one dimensional. Even just the small sections of garden visible on our side of the fence, in contrast, exhibit species diversity, ground cover diversity, ground water recharge through passive rainwater harvesting, structural diversity through the trees, bamboo stakes, and remains of sunflowers that are available for use by all sorts of creatures. It is a truly different environmental situation.

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Not only is our soil being actively protected by living ground covers and leaf litter, but we have winter crops growing as well. Self-sown lettuce and mustards along with daikon radish and wild crops such as dandelions, chickweed, and henbit are thriving in these conditions. While small, their great number allows for periodic harvest without inhibiting the plants ability to gather and store energy. Permaculture based gardens are dynamic and multi functional, which is difficult for many people to understand.

Lengthening days at the end of January provided the plants with just enough energy to begin moving towards reproduction (Photograph 3-5 opposite). While not visible yet, the cabbages (bright
yellow) were well on their way towards flowering. Abundant standing stalks from the year prior along with diverse mulch materials act like insect hotels without the fuss of constructing them. Where you see orange, this is evidence of my collection of pine needles to use as mulch on the pathways. One can also observe, center left, the soil enriching qualities of comfrey by the dark, nearly black, layer of leaves that has begun to form around one growing on the second swale’s mound.

Seen from above (Photograph 3-6), the garden appears well organized, even without enough pine needles to mulch all of the pathways. The house, situated up slope from the garden, combines with
the low angle of the winter sun to cast deep shade throughout the majority of the garden. Only the river birch (white tree, center left) and its environs escape most of the shadow’s march. While this is not so much of an issue mid winter, it does become a problem in early spring when plants are flowering: the rapid shift in temperature can be enough to cause bud drop! It is important to track the movement of deep shade cast by buildings or other features and plan accordingly (that is, don’t plant something borderline for your zone in a place where it will be hit by sudden changes in temperature!).

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When February came around, temperatures warmed up enough that I could complete the mini hugel mounds underneath the pine trees. I had to move a huge pile of clay that had been dumped in one
spot when my brother and his friends dug out part of the pond while I was away in the summer. Once that was out of the way, I could finally get around to digging out the rest of the pond at my own pace. Not only did I have time to finalize these earthworks, but the wildlife in the garden was beginning to stir as if spring was already upon us.

At the end of February, we had our only snow of the season which mostly melted away by midday. The following two pages demonstrate the effects of microclimates are readily apparent: snow
melt follows deep shade (you can clearly see where the fence line was) and southern aspects (the left/ southern side of the swale mounds have melted completely while the right/north still have snow). Both of these facts are on display in the final image.

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Water Harvesting and Feature Upgrades

Water features- ponds, swales, etc. are all systems that will be continually adjusted and played around with as long as you live with them, especially on this scale. Our property is just large enough to accommodate many different kinds of earthworks and water features. Observing the interactions between the terrestrial growing beds and our aquatic ones is a joy. Even though the ponds are not well established yet: we could use many more plants along the edges and within them, they still provide us with many different benefits. Photographs 3-18 & 3-19 reveal how seamlessly these features blend into the landscape: subtle, yet beneficial.

Winter in North Carolina can be a good time to do some digging: temperatures are comfortable for long periods of manual labor. It is also a season when precipitation is greater than evaporation: therefore, any earthworks done during this period will infiltrate more water than during the summer months. We do not experience any larger quantities of precipitation in the winter here, but we want to capture as much water as possible. Additionally, since the cover crops were taking care of themselves, I could go ahead and fix some errors.

Towards the middle of February I was able to bring the lower pond to a holding stage. I was very excited about this because up until then we hadn’t had any fish in there due it lacking the fish kettle and number of steps I thought would make for a good start. I took the time to manually remove a lot of water from the pond (and put it in the swales) to draw the water level down so I could work. Excavating a small pond is similar to a strip mine: you dig each successive layer lower while allowing space to steer the wheelbarrow down each step via ramps. In this way, you create a nice stepped pond which allows for diverse plantings (that each require a different water level) as well as providing shallow and deep portions for aquatic life. I eventually dug
down about 8 feet deep to create a “fish kettle” in case the goldfish would need to escape a real winter.

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I intentionally left the area to the west, where the pond overflows, shallow and narrow (as well as being the start of the ramp for the wheelbarrow) to compensate for not putting in any kind of “key” for the “dam.” Since the overall quantity of water being stored here is actually quite small, I did not feel that going through the work to “key” the downhill side of the pond would be necessary. Still, better to leave a very large wedge of soil between the “wall” (water exit site in this case, where there wouldn’t be any wall) and the deeper sections of the pond. As I write, the pond has been completed for two and a half years and we haven’t experienced any problems. The pond has overflowed its bounds on numerous occasions and remained intact. Keep in mind that in
addition to the pond being dug into soil rather than being backed up with a wall that the soil is severely compacted from the construction of the house, so there are many factors in play here that help keep these ponds from becoming disasters. Lastly, it would probably be more accurate to describe them as pools rather than ponds!

I used some of the extra clay from the pond excavation to put elbows on both swales. Previously, whenever the swales would fill, they would overflow around either end. Not only that, but their maximum fill level was much lower because of this situation. By adding an elbow of soil (clay) to the eastern end, I could back more water up in the swales and direct the overflow in a single direction. In the case of the upper swale, this would direct water west, which also happens to be a small ridge. In this way, I am taking excess water from the valley end (east) and
watering the drier ridge. The second swale, because it was dug off-contour, however, still had a problem of water accumulating in the center. I would have to amend this later.

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In Photograph 3-22 you can see how the garden slopes towards the bottom left corner of the image into the “valley” where the ponds are situated. It is clear that the area near the house and dog fence is much higher than where the second swale abuts the fence. In keeping with the permaculture mantra of storing water as high in the landscape for as long as possible (and the keyline principle of watering ridges from valleys), by blocking the lower edge of the swales with elbows, I was keeping water in the system for longer. A lot more work remains towards the center of the garden so that we can move water along the longest edge possible (another permaculture water principle). If water is allowed to flow along the fence line, it is shunted out of the system much faster and we do not receive as much benefit from it.

How did this work out in practice? Well, just four days later, we had our first snow. It did not stick around very long (Photographs 3-15 – 3-17 p. 74-75) so we had to wait a few more days before a swale filling rain event would come our way.

The upper swale fills more regularly than the bottom due to its smaller size as well as being the first catchment we have, arresting water before it can get to the second. Growth along it has been strong since implementation and I have considered digging it even deeper. This may happen the next time I travel back and prepare a site for a persimmon tree. Still, it works as intended. Bamboo stakes on the mound (left of water) mark where new comfrey cuttings were planted a few weeks prior. Now the entire length of both swales have been planted with comfrey to close gaps in our nutrient nets.

The second swale also filled on the same day and it became quite clear that I would need to do something to rectify its propensity to overflow in the center. I knew that something had to be done when it overflowed the previous summer and helped wreck the four sisters guild as it made its way through the loose soil and into the lower pond. Luckily, this particular rain had stopped just short of that critical point.

The blocking of the fence-side overflow meant that, finally, given enough rain, the swale would fill along its entire length. Looking at the bottom left, you can see how it appears there is
less water than center (and the swale continues in a curve all the way to the fence). This is before I remediated the swale using steps (Figure 2-8, p. 34), so the western edge of the swale does not receive as much benefit. This is because as captured water infiltrates into the ground, the water level drops and the remaining water concentrates towards the center and east from the western edge. Still, putting the elbow on the end has enabled more water than before to enter all sections of the garden adjacent to the swale.

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To ensure that the swale no longer breaches the berm, I installed a “monk-like” device at the east end. Photograph 3-25 (next page) shows the location of the “monk,” while Figure 2-8 (p. 34) depicts its inclusion as well. Essentially, the idea (a monk is just another word for overflow pipe) is adopted from Sepp Holzer’s method of controlling the water level in his ponds. An adjustable pipe is situated with the mouth controlling the highest level desired. When water reaches this mouth, it enters the pipe and is sent to another water harvesting feature. In this case,
the short pipe elbows through the swale mound and down to the upper pond. This is a failsafe measure and only in the most extreme weather events does it do this. I would like to adjust this in the future to be a little lower so that we can have an overflow on the ridge as discussed earlier.

When it comes to the swales, it really becomes quite clear why designers like Ben Falk and Geoff Lawton are so adamant about their inclusion in spaces like this- and why they are always seeking to increase the number of them on a property. To actually watch earthworks you dug catch, hold, and infiltrate water throughout the entire year is positively reinforcing. When considered in conjunction with a deepening topsoil and the root/ fungal networks developing there, I can appreciate how it can, as Geoff Lawton says, take up to 7 years before a landscape is rehydrated. We were only starting the second year of swales and already the landscape was responding. I look forward to seeing the garden in 2017!

Photograph 3-25 also shows quite well how the garden is responding to our treatment and cover crop: quite lush and flowers of many species creating ideal conditions for prolonged ecological activity. Again, notice how swale is well and level until the middle section, before it climbs uphill. Making the mistake, however, has been the best teaching tool regarding earthworks because I’ve developed new ideas as to how to compensate and turn them into a potential solution. My eyes have been opened to the potential benefits of using ditches and swales in conjunction, which greatly increases the possibilities of structural diversity when it comes to water harvesting.

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Figure 3-1 depicts the changes made during the course of spring and early summer of 2012. The addition of elbows to the swales has rerouted surface runoff. This has worked well for the first swale, although still not ideal as the overflow is not purposefully directed anywhere (although the second swale can capture some of it since it extends further west than the first swale).

As just discussed, the addition of the monk (greatly exaggerated in size here [pink “Overflow Pipe”]) has stopped the water from overflowing in the center of the second swale. But it has also
prevented the water from overflowing in the center of the garden (to the ridge)- so this is something I would like to address in the coming years. Comfrey has been divided and planted densely along the length of both swales, consolidating the nutrient net (see Site Preparation Conclusions p. 27-29). These new cuttings need a good year before being actively harvested.

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Lastly, I have chosen to depict the addition of Zai Bowls before they were dug in early summer. Zai bowls, mulched with wood chip, will capture and infiltrate water before it reaches the second swale. These bowls, each at least 20 gallons (75 liters) in capacity, are connected to one another through small overflow depressions. They are filled with wood chip mulch, which makes it easy to walk along the fence line without risking breaking a leg! The wood chip also will become saturated and thus become a feeding zone for fungi and tree roots. The mass of wood chips and the ensuing fungal network also affords another level of biological filtration between the neighbor’s lawn, which is treated chemically, and the main garden area. Eventually, Zai bowls could be dug along the entire fence line. I believe they are an excellent means of harvesting water even in humid landscapes. Their only drawback, in this instance, is the need to be filled with some kind of mulch to prevent injury- ground covers grow exceptionally tall near them and so their presence can become masked to those who are unaware of their existence. Still, they allow for water to be “slowed, spread, and sunk” in places where more “traditional” earthworks would not function.

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