Monday, January 9, 2012

Dynamic Accumulators for Temperate Climates

Symphytum officinale, Common Comfrey, is one of the best dynamic accumulators.

This is a term that I first came across in Dave Jacke’s book, Edible Forest Gardens.  In brief, it is the idea that certain plants (often deep-rooted ones) will draw up nutrients from the lower layers of the soil, and these nutrients will be deposited in the plants’ leaves.  When the leaves fall in autumn and winter and are broken down, those stored nutrients are then incorporated into the upper layers of the soil where other plants will benefit from their deposition.

This is a natural method of increasing soil fertility.  It is likely one of the ways that forest ecosystems continue to thrive and remain stable with minimal external inputs.

This is also a great Permaculture tool.  By observing nature, we can mimic nature, and we can have great results with minimal effort.  As I always say, Permaculture is about design!

We can sustainably and naturally increase our land's soil fertility by using dynamic accumulators.  It can be done with almost no work, other than planting or sowing seed, and allowing nature to do what it naturally does on its own.

We can expedite the process a bit, and increase our work a bit, by cutting back fast growing plants to encourage more frequent plant growth during the growing season.  For instance, chopping a bunch of mature leaves off fast growing Comfrey will provide high nutrient green mulch.  We can drop them where they fall or redistribute them to other locations that are low in nutrients.

There are a number of other ways to incorporate dynamic accumulators.  I'll be addressing these in an upcoming article.

The tiny flowers of Stellaria media, Common Chickweed, a dynamic accumulator that has a lot of Permaculture benefits... poultry food (hence the name), ground cover, and dynamic accumulator!

The science of dynamic accumulators is an area of botany with very little research to date.  We know it is true, but unfortunately not a lot of time has been spent studying the concept of dynamic mineral accumulation, so we only have research on a few plants.  Hopefully with time, we will be able to add substantially to this data.

Here is a list of well studied dynamic accumulators that can be used in a Temperate Climate.   The nutrients that they provide are abbreviated in bold:
  1. Sugar Maple,  Acer saccarum K, Ca
  2. Maples,  Acer spp.  K
  3. Yarrow,  Achillea millefolium  K, P, Cu
  4. Chives,  Allium schoenoprasum  K, Ca
  5. Black Birch,  Betula lenta  K, P, Ca
  6. Birches,  Betula spp.  P
  7. Shagbark Hickory,  Carya ovate  K, P, Ca
  8. Hickory, Pecans,  Carya spp.  K, Ca
  9. German Chamomile,  Chamaemelum nobile  K, P, Ca
  10. Chicory,  Cichorium intybus  K, Ca
  11. Flowering Dogwood,  Cornus florida  K, P, Ca
  12. Horesetails,  Equisetum spp.  Ca, Co, Fe, Mg
  13. Beeches,  Fagus spp.  K
  14. European Beech,  Fagus sylvatica  K, Ca
  15. Strawberry,  Fragria spp.  Fe
  16. Wintergreen,  Gaultheria procumbens  Mg
  17. Licorices,  Glycyrrhiza spp.  P, N
  18. Black Walnut,  Juglans nigra  K, P, Ca
  19. Walnuts,  Juglans spp.  K, P
  20. Lupines,  Lupinus spp.  P, N
  21. Apples,  Malus spp.  K
  22. Alfalfa,  Medicago sativa  Fe, N
  23. Lemon Balm,  Melissa officinalis  P
  24. Peppermint,  Mentha piperita  K, Mg
  25. Watercress,  Nasturtium officinale  K, P, Ca, S, Fe, Mg, Na
  26. Silverweed,  Potentilla arserina  K, Ca, Cu
  27. White Oak,  Quercus alba  P
  28. Black Locust,  Robinia pseudoacacia  K, Ca, N
  29. Sorrels, Docks,  Rumex spp.  K, P, Ca, Fe, Na
  30. Salad Burnet,  Sanguisorba minor  Fe
  31. Savory,  Satureja spp.  P
  32. Chickweed,  Stellaria media  K, P
  33. Comfreys,  Symphytum spp.  K, P, Ca, Cu, Fe, Mg
  34. Dandelion,  Taraxacum officinale  K, P, Ca, Cu, Fe
  35. Basswood,  Tilia Americana  P, Ca, Mg
  36. Linden (Lime in the UK),  Tilia spp.  P, Ca
  37. Clovers,  Trifolium spp.  P, N
  38. Stinging Nettle,  Urtica dioica  K, Ca, S, Cu, Fe, Na
  39. Vetches,  Vicia spp.  K, P, N
  40. Violets,  Viola spp.  P

Abbreviation Key
Ca = Calcium
Co = Cobalt
Cu = Copper
Fe = Iron
K = Potassium
Mg = Magnesium
N = Nitrogen (in this case, these plants are nitrogen fixers)
Na = Sodium
P = Phosphorus
S = Sulfur


  1. Hello I was wondering if the dynamic accumulation of any of the plants on the list have been studied in a quantitative fashion. If so can you give a citation? My understanding is that this point it is highly criticized by many scientists who write permaculture off as a pseudo-science. I personally have a fairly rational explanation for how it works (and believe a number of people do). Did Bill Mollison originally propose it or did someone else? If no-one has demonstrated it in a reductive/quantitative manner then I will do my best to test it.

  2. Is your 'rational explanation' about accumulators or about permaculture? Maybe I misunderstood your comment.
    Very little scientific research has been carried out on plants and their ability to accumulate particular minerals. Most info seems to be presented in popular books and in permaculture forums and blogs.
    The whole notion of dynamic accumulators was developed way before Mollison and Holmgren developed the permaculture concept.
    I am a scientist, who has written and taught extensively about permaculture, and my observation is that it builds on the ideas of ecological design, and promotes concepts based on science. While I acknowledge there are some permaculture practitioners who have some unusual beliefs, these are not held by authoritive permaculture writers and teachers. Ross Mars

    1. I am not sure I understood your comment, are you saying that there is little evidence for plants accumulating minerals in their tissues, or are you saying there is little research on particular minerals?

      I found this in a quick search, and the science for plants accumulating minerals is well established (I serached for "plant mineral accumulation" in Google scholar):

      There is plant in New Caledonia which accumulates Nickel in it's sap to about 1%, and accumulation of nitrates in leafy greens is a well known phenomenon. Aluminium accumulation in NZ pastures in acid soils, Cadmium accumulation, radioactive isotopes... the fact of plants accumulating minerals appears well established in the scientific literature, so I don't quite understand what you were trying to say in your comment.
      Please explain

  3. Ben, below is a link to a spreadsheet that is well documented with citations & actual numbers of how many mg are being accumulated:

    1. This spreadsheet was empty. Can you resent it please?

    2. Looks like the person took it down but I found it again here:
      and it's downloadable

  4. I'd be wary of using black walnut as a dynamic accumulator as the leaves and roots are allelopathic and will retard the growth or outright kill many plants. There is a list of plants that can tolerate black walnut on Clemson Extension's website.

  5. Does anyone know if Trumpet Vine is a good chop and drop plant? It grows so vigorously I have to cut it back weekly to keep it from taking over the yard. Do I drop it or send it away? Thanks!

  6. This comment has been removed by the author.

  7. Maybe Arctium lappa (plant with taproot) too?