Mounded gardening technique
Hugelkultur
(
German pronunciation:
[?hyː?l?k?l?tuː??]
), literally
mound bed
or
mound culture
, is a
horticultural
technique where a mound constructed from decaying wood debris and other
compostable
biomass
plant materials is later (or immediately) planted as a
raised bed
. Considered a
permaculture
practice, advocates claim that the technique helps to improve
soil fertility
, water retention, and soil warming, thus benefitting plants grown on or near such mounds.
[1]
[2]
History
[
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]
Hugelkultur is a German word meaning mound culture or hill culture.
[3]
Though the technique is alleged to have been practiced in German and Eastern European societies for hundreds of years,
[1]
[4]
the term was first published in a 1962 German gardening booklet by Herrman Andra.
[5]
Inspired by the diversity of plants growing in a pile of woody debris in his grandmother's garden, Andra promoted "mound culture" as opposed to "flatland culture".
[5]
This was also posited as an easy way to utilise woody debris without burning, which was illegal.
[5]
Andra appears to have been influenced by
Rudolf Steiner
's
biodynamic agriculture
. Steiner explained his biodynamic philosophy as developed through
meditation
and
clairvoyance
, on the grounds that his methods were “true and correct unto themselves.”
[6]
Andra quotes a 1924 lecture on biodynamics by Steiner, which describes mixing of soil with composting or decaying material in earthen hillocks.
[5]
Joined by author Hans Beba, another German gardener, "Hill Culture - the horticultural method of the future" was revised and republished several times in the 1970s and 1980s.
[5]
[7]
The technique was later adopted and developed by
Sepp Holzer
, an Austrian permaculture advocate.
[8]
More recent permaculture advocates such as
Paul Wheaton
strongly promote Hugelkultur beds as a perfect permaculture design.
[9]
Construction
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]
In its basic form, mounds are constructed by piling logs, branches, plant waste, compost and additional soil directly on the ground. The pile has the form of a pyramid. (Note?Wheaton suggests piling the wood higglety-pigletty rather than in a neat stack as shown, for structural engineering of the steep slope, or perpendicular to the spine of the mound.) The sides of the two slopes both have a grade of between 65 and 80 degrees.
[10]
The beds are usually about 3 by 6 feet (0.91 by 1.83 m) in area and about 3 feet (0.91 m) high.
[1]
However, this height reduces as decomposition progresses.
[5]
When positioned on sloped terrain, the beds need to be placed on contour or put at an angle to the hillside (rather than parallel to it). This makes sure the beds do not receive unequal amounts of water. In most cases, it is useful to have the beds positioned against the prevailing wind direction.
The raised bed can form light-duty
swales
, circles and mazes.
[11]
[12]
Mounds may also be made from alternating layers of wood, sod,
[13]
compost, straw, and soil. Although their construction is straightforward, planning is necessary to prevent steep slopes that would result in erosion.
[8]
[4]
In his book
Desert or Paradise: Restoring Endangered Landscapes Using Water Management, Including Lake and Pond Construction
, Holzer describes a method of constructing Hugelkultur which incorporates rubbish such as cardboard, clothes and kitchen waste. He recommends building mounds that are 1 meter (3.3 ft) wide and any length. Mounds are built in a 0.7 meters (2.3 ft) trench in sandy soil, and without a trench if the ground is wet.
[10]
Planting
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The mound is left to rest for several months before planting,
[5]
although some advise immediate planting.
[
citation needed
]
Anything can be grown on the raised beds, but if the bed will decompose/release its nutrients quickly (so long as it is not made of bulky materials like tree trunks), more demanding crops such as pumpkins, zucchini, cucumbers, cabbages, tomatoes, sweet corn, celery, or potatoes are grown in the first year, after which the bed is used for less demanding crops like beans, peas, and strawberries.
[
citation needed
]
Lifespan
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]
The original German publications described the mounds as having a lifespan of 5?6 years, after which they had to be rebuilt from scratch.
[5]
Evidence
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]
As of 2017 there are no peer-reviewed scientific studies available regarding the efficacy of the technique.
[5]
A few university student projects investigate Hugelkultur but have not been published in scientific journals.
[5]
One small scale and short term student project investigated the Hugelkultur method as a potential use for yard trimmings waste, and also if lima beans, kale and okra planted on a Hugelkultur mound showed any signs of nutrient deficiency compared to a non-raised control bed. It was found that over 11 tons of yard trimmings were used in the mound, and no evidence of macronutrient deficiency could be detected in the crops in the short term.
[14]
Indeed, despite concerns that incorporation of large quantities of high carbon woody matter would lead to nitrogen immobilization and hence nitrogen deficiency in the crop, a higher level of nitrogen was found in the raised bed. However, the micronutrient iron was lower relative to the control bed.
[14]
The author speculated that no nitrogen deficiency occurred since the roots of the plants did not penetrate past the superficial layers of the mound into the deeper wood-containing region.
[14]
A student thesis investigated the water holding capacity of Hugelkultur beds and whether the technique could be useful to prevent
karst
rocky
desertification
in China.
[15]
Over 3 months of measurements, water concentration in hugel mounds remained high. Samples from hugel sites contained almost twice as much water as those from flat control plots. It was suggested that
1 ha (
2
+
1
⁄
2
acres) of hugels has 3-10 times more water than a flat plot affected by karst rocky desertification.
[15]
Theory
[
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]
Many publications and websites advocate the technique based on personal experience of the authors.
[5]
Some have criticised the technique as lacking genuine scientific principles, and running counter to the ecological principles of soil building with
litterfall
.
[5]
Hugelkultur is said to replicate the natural process of decomposition that occurs on
forest floors
, however in natural ecosystems wood would be present at the soil surface.
[5]
Trees that fall in a forest often become
nurse logs
[8]
decaying and providing
ecological facilitation
to seedlings. As the wood decays, its porosity increases, allowing it to store water like a sponge. The water is slowly released back into the environment, benefiting nearby plants.
[1]
These beds are also considered beneficial because of the airpockets created by the settling caused by the wood's decomposition. This gives the benefits of tilling, without the destruction of soil microorganisms that come with tilling ("every time you till the soil, you lose 30% of the organic material (microbial soil life is killed, and plants feast on their bodies)"
[16]
). And, the organic material of the rotting wood also houses beneficial soil microorganisms.
[16]
Hugelkultur beds are said to be ideal for areas where the underlying soil is of poor quality or compacted. They tend to be easier to maintain due to their relative height above the ground.
[8]
The decomposition speed of organic material depends on the
carbon to nitrogen ratio
of the material, among other factors. Wood breaks down relatively slowly because it has one of the highest carbon to nitrogen ratios of all organic matter that is used in composting. If the wood is not processed into smaller pieces with larger surface area to speed up chemical reactions, breakdown is even slower. The decomposition process may, in the short term, take more nitrogen from the soil through microbial activity (
nitrogen immobilization
), if not enough nitrogen is available.
[17]
Thus, in the short term, the fertility of the soil may be decreased before, eventually, perhaps after one to two years, the nitrogen level is increased past the original level.
[17]
Traditionally, therefore, it is said to be advantageous to balance "browns" (e.g. woodchippings) with "greens" (e.g. grass clippings) for efficient composting, and to allow compost to become well-rotted before applying it to a bed, to prevent competition between soil bacteria and plants for nitrogen, which reduces yield.
Criticisms and controversy
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Hugelkultur mounds as solid earthworks
[
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]
Although Hugelkultur beds can safely retain water in light-duty applications (for example, conserving the moisture of rain that falls on the bed), creating heavy-duty rainwater retention areas behind Hugelkultur beds on contour, to catch
surface runoff
from surrounding areas, can be dangerous. Some designers conflate the Hugelkultur bed's appearance with that of solid
earthworks
, but Hugelkultur beds cannot predictably control large amounts of
stormwater
in the way that solid earthworks can. Whereas
embankment dams
or the hillsides of
swales
can be relied on to hold back many thousands of gallons of water for weeks to allow it to seep into the ground, and
berms
can slow runoff, Hugelkultur beds are different in two ways: earthworks have no buoyant core (whereas Hugelkultur mounds contain logs), and the soil that they are made of is compacted. If fresh or dried timber is used in the bed, it may become buoyant in the water-saturated substrate, bursting from the soil covering and releasing all the sitting water through a breach. This can be an issue for years, until the wood is sufficiently rotten and infused with water. Another consideration is that Hugelkultur beds will degrade, shrinking over time into much lower mounds of soft, rich soil. This means that the retention area will have less depth as time goes on, but it also means that the uncompacted soil will remain a threat to breaching even if the logs become saturated.
Some permaculturists have taken mild positions against the "hugel swales" still being promoted by other permaculturists, citing the danger and cross-purposes of Hugelkultur beds and swales. Swales are for long-term installations where perennials - like fruit trees - are grown. Hugelkultur is used for shorter term, more annual crops, as the soil settling that occurs with hugel decomposition is bad for the root system of fruit trees.
[18]
A common practice is to plant fruit trees beside a hugelkultur mound where some nutrient runoff can feed the tree without the tree’s support collapsing under it, while also allowing the tree to extend its roots laterally under or upward into the hugelkultur mound as far as it “needs.”
There is a recorded instance of a breach occurring in a new project. Upon the first rainstorm, the retention areas behind the Hugelkultur beds filled with water and broke through. The released water carried the freshly-buried logs and dirt downhill, smashing a hole in a building being used as a church and filling the space with mud. No injuries were reported.
[19]
Overfertilization, contamination of soil and water habitats
[
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]
Over-fertilized plants are said to have less flavor,
[20]
and too much nitrogen can be consumed by eating certain plants which have been over-fertilised (e.g., spinach).
[20]
Advocates state that overfertilization is a risk in the first year if woodchips are used, which will break down too fast.
[20]
Instead raised beds made with whole logs release nutrients slowly over a period of years.
[20]
It has been suggested that excessive use of decomposing organic matter in Hugelkultur could leach out and contaminate and disrupt soil and water habitats.
[5]
See also
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References
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- ^
a
b
c
d
Miles, Melissa (August 3, 2010).
"The Art and Science of Making a Hugelkultur Bed ? Transforming Woody Debris into a Garden Resource"
. The Permaculture Research Institute
. Retrieved
May 2,
2014
.
- ^
"The Many Benefits of Hugelkultur"
. Permaculture Magazine. October 17, 2013
. Retrieved
May 2,
2014
.
- ^
Lauterbach, Margaret (February 2, 2012).
"Margaret Lauterbach: Clippings fuel fertile 'hugel' mounds"
. Boise, ID.
Idaho Statesman
. Retrieved
May 3,
2014
.
- ^
a
b
Martin, Claire (April 11, 2014).
"Hugelkultur, translated: A path to richer soil"
. Denver, CO.
Denver Post
. Retrieved
May 2,
2014
.
- ^
a
b
c
d
e
f
g
h
i
j
k
l
m
n
Chalker-Scott, Linda (August 2017).
"Hugelkultur: What is it, and should it be used in home gardens?"
(PDF)
. Pullman, Washington : Washington State University Extension.
doi
:
10.7273/000004616
.
hdl
:
2376/12233
. Retrieved
8 July
2018
.
- ^
Chalker-Scott, Linda (December 2013).
"The Science Behind Biodynamic Preparations: A Literature Review"
.
HortTechnology
.
23
(6): 814?819.
doi
:
10.21273/HORTTECH.23.6.814
.
S2CID
39059239
.
- ^
Beba, Hans; Andra, Herrman.
Hugelkultur ? die Gartenbaumethode der Zukunft
(10th ed.). Mannheim, Germany: Waerland.
- ^
a
b
c
d
Palmer, Kim (August 14, 2013).
"A Garden Made of WOOD; Hugelkultur (Hooogellocullocher or Hewogellocullocher) A Nature-Inspired Method of Gardening in Beds Built on Logs, Touted as a Drought-Resistant Way to Produce Food"
. Minneapolis, MN. Star Tribune
. Retrieved
May 2,
2014
.
- ^
Wheaton, Paul,
hugelkultur: the ultimate raised garden beds
, retrieved 6/9/2014
- ^
a
b
Holzer, Sepp (2012).
Hugelkultur
. Chelsea Green Publishing. pp. 131?134, 139.
ISBN
978-1603584647
.
- ^
Hemenway, Toby (2009).
Gaia's Garden: A Guide to Home-Scale Permaculture
. Chelsea Green Publishing. pp. 84?85.
ISBN
9781603582230
.
- ^
Feineigle, Mark (January 4, 2012).
"Hugelkultur: Composting Whole Trees With Ease"
. The Permaculture Research Institute
. Retrieved
May 2,
2014
.
- ^
Shein, Christopher (2013).
The Vegetable Gardener's Guide to Permaculture: Creating an Edible Ecosystem
. Timber Press. p. 28.
ISBN
978-1604692709
.
- ^
a
b
c
Adams, A (May 2013).
"UNIVERSITY OF WISCONSIN SYSTEM SOLID WASTE RESEARCH PROGRAM Student Project Report: Hugelkultur Gardening Technique Does not Result in Plant Nutrient Deficiencies and is a Potential Source Reduction Strategy for Yard Trimmings Wastes"
(PDF)
. Archived from
the original
(PDF)
on 2021-02-20
. Retrieved
2018-07-08
.
- ^
a
b
Laffoon, M (August 2016).
"A Quantitative Analysis Of Hugelkultur And Its Potential Application On Karst Rocky Desertified Areas In China"
.
- ^
a
b
Wheaton, Paul (2019).
Building a Better World in Your Backyard, Instead of Being Angry at the Bad Guys
(New ed.). USA: Shawn Klassen-Koop. p. 74.
ISBN
978-1999171407
.
- ^
a
b
Seymour, John (2008).
The new self-sufficient gardener : the complete illustrated guide to planning, growing, storing and preserving your own garden produce
(New ed.). London: Dorling Kindersley. pp.
12
, 13.
ISBN
978-1405321334
.
- ^
"Hugels as Swales??"
. permies.com. Jan 14, 2015
. Retrieved
March 30,
2020
.
- ^
Spirko, Jack (November 6, 2015).
"Don't Try Building Hugel Swales"
. permaculturenews.org
. Retrieved
March 17,
2016
.
- ^
a
b
c
d
Holzer, Sepp (2011).
Sepp Holzer's Permaculture: A Practical Guide to Small-Scale, Integrative Farming and Gardening
. Chelsea Green Publishing.
ISBN
9781603583831
.
External links
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