Wednesday, 26 November 2014

Continuing to raise the allotment with trench Hugelkultur (4)

I had just scraped up the last of the woody shreddings and put them into the wheelbarrow when I got a call from the gate by a gardener with a load of woody shreddings.  Opportune or not? They backed the lorry into the carpark and tipped the shreddings into my composting area.  This will last me about a week or two.

It was great because I was not looking forward to trundling the wheelbarrow down to the main car park to fetch the woody shreddings from there.  A time consuming exercise.

I have nearly finished trenching the first section of the allotment but the final trench is alongside the path where it was full of mare's tail Equisetum arvensis and bind weed Calystegia sepium.  Removing these rhizomes is a tedious and slow task, however if not done with some efficiency it will cause a lot more work in the future.

It is reported that leaving even small pieces of the rhizome in the soil will produce regrowth of the plants.

The example of micropropagation shows that plants can be generated from the smallest of pieces of material.  However, I wonder the size of the smallest piece of rhizome that can regenerate plants when in the wild.  Do we accept the assertions of pundits in gardening books and on television or do we investigate for ourselves?

So, when I have time, I will be planting smaller and smaller pieces of Equisetum and Calystegia in ordinary allotment soil using 3 inch pots and keeping them in the greenhouse to see if any produce plants.  I reckon that any rhizome without a rooty node will not regrow.  Further, any rhizome smaller than a particular size will not grow.   

However, knowing these particularly, pernicious plants I would not be surprised if they did regenerate from the smallest of pieces.

I have been amazed  by the number of Stigmatogaster subterranea I am finding in the soil.  I think that it is fairly common in the West Midlands.  They are a good predator of slugs and soil pests so I would like to encourage them.  It is amazing the close interaction of invertebrates like these with the soil.  Worm burrows fit the worms much more intimately than a hand in a glove.

Stigmastogaster subterranea 
So, it takes a while to remove all the perennial rhizomes from the top soil using the bread tray sieve.  Moreover, I am not stupid enough to expect I have removed them all, but I have been pleasantly surprised how little if any Calystegia sepium or Equisetum arvensis  has regrown on any of the areas of the allotment that I cleared with the sieve last season.
Bread tray sieve.
Mare's tail and bindweed seem to grow well in poor soil where there is little competition from other plants.  Both perennial rhizomes are not seen where there are healthy nettle and comfrey plants growing; primarily because they shade out the mare's tail and bindweed. To ensure that they do not return, I will make sure that the ground is well fertilised and the crop plants form a good canopy to shade out any weeds that might grow between them.

As usual the bottom of the trench was forked over - and I was still removing mare's tail from the subsoil clay.  This plant forms extensive rhizome nets throughout the soil, which means that they can throw up aerial shoots over a wide area wherever there is little competition.   Also this wide ranging net of rhizomes can store a great quantity of food so that even when light is excluded - as when the ground is covered with carpets, black plastic or other opaque sheets, they can still grow from underground stems when the soil coverings are removed.  Breaking up this net by digging will reduce the amount of food that tiny pieces left in the soil have to rely on and this may further reduce their viability.  

In order to increase the fertility and organic content of the soil, I am adding logs, brushwood; processed wooden planks; at least a six inch layer of woody shreddings; comfrey liquid; sieved top soil from the path mixed with a little chicken manure and farmyard manure before pulling the sieved topsoil from the trench back over with the rake.   

I'm not really sure whether trenching like this has any particularly beneficial effect on the yield of vegetables I harvest from the allotment, however it keeps me fit and active.  

I took the oca out today and washed the tubers.  I will keep all of the tubers to build up my stock. They will have to be carefully dried and stored in paper bags until next season. The parsley was planted in their stead because it is a little shady behind the greenhouse.  Parsley will grow in partial shade.  

I may also plant a gooseberry there as well.  

I will have to sort the little greenhouse out because it has sunk even further where I have trenched around it.  It will not take long to remove the glass and raise it up but fitting this in when I am digging is quite difficult.  I will finish digging first.


  1. You need an assistant!

    1. Hi Andy, any time you are over here and I will buy you a scotch afterwards.

  2. What a splendid name, you must have made it up. I jest! To me its just a beneficial yellow centipede! Actually I blogged ages ago about how so many gardeners think it to be a wireworm!
    You forking out all those rhizomes reminded me of my youth forking out couch grass.
    I will be very interested in your pot trials

    1. Hi Roger I often think that I could easily make up latin sounding names to impress people with. Its not difficult. However, this one is real. I was never one for names finding that, as a biologist, I could get away with just a few. However, it is good to be able to shout out, "Be careful with that Stigmatogaster".

      One of my friends says their children think plant names sound like a Harry Potter spells.

  3. I'll take you up on that scotch one day... once I get my own garden in order!