Starting to clear and triple dig an allotment (10)

Finished trench 9 and about to begin trench 10.  I am still using the shredded goat willow Salix caprea as a carbon source to put at the bottom of the trenches.  In the past I have used Cupressocyparis leylandii shreddings or any other that I could get my hands on.

Using Cupressocyparis leylandii shreddings

A few years ago, I would never have done this.  I thought that adding carbon like this would deplete the soil of nitrogen.  Microorganisms need nitrogen to make proteins and nitrogen is gleaned from the soil around the shreddings.  However, I have always buried the shreddings quite deep in a trench Hugelkultur and allowed the shreddings to decompose before bringing them up nearer to the surface when making the next trench.  

Quercus robur logs and branches

What fascinated me was that there seemed to be no nitrogen deficiency in the area of the the trench. Vegetables, which are notoriously nitrogen dependent, grew normally with no sign of lack of nitrogen.  

On the new allotment the soil is particularly thin lacking dead organic matter.  This means that the characteristics of the clay becomes very dominant.  With the deep digging, it is much easier to fork over, however the soil is very heavy and tends to cap over after the rain - and we have had a lot of rain recently.  

Adding the shredded goat willow Salix caprea will add dead organic matter to the soil but this will take time to decompose and be mixed with the top soil so I will have to invest in some horse or farmyard manure to dig into the top soil.  This manure will rot down much quicker and be incorporated to make the soil much more open and friable.  

The soil is heavy because clay holds a lot of water.  Adding dead organic matter will allow a clay soil to drain much quicker.  Adding gravel will also open the soil and make it lighter and I was going to do this until I read about rock dust which will also add nutrients - or so the theory would lead us to believe. I bought some rock dust and am adding it to both replenish nutrients and to improve the structure of the top soil.  I know there is some debate about adding rock dust but I can find very little academic research about it at the moment.  I will continue to look for some academic validation for adding rock dust but I am not optimistic about finding any.

I am using two foot square concrete slabs to make the path down the side of the allotment.  The original top soil from the path has been sieved to get the weed rhizomes out and put onto the growing areas.  The hole that is left is filled with stones that have been sieved from the growing area.  A little of the clay subsoil is put over the stones to make it easier to level and the concrete slabs have been put on top of the subsoil.  

Adding the shredded brushwood material has raised the allotment above the level of the path and has meant that a curb has to be put down the side of the path to keep the top soil from falling onto the path.  I am using 50 square centimeter slabs for this job, however I am quickly running out of them so I will use the two foot square slabs as curbing when necessary.  

While it is possible to still dig when the ground is saturated due to the rain we have been having over the last week, it is not very pleasant particularly where the soil contains a lot of clay.   So, leaving the ground to dry out a little, I will do some moving plants around.  The fruit trees are now fully dormant so, when there is a little relatively dry and warm weather, I will move the apple trees into their permanent positions.  I am trying to find places where they will get maximum sunlight but will not overly shade the allotment.  

I have already decided to plant the strawberries Fragaria ananassa between the new compost bays and the grape vine, Vitis  vinifera.  I have sown some green manure in this area and will have to dig it in as I plant the strawberries.  Fragaria ananassa  seems to respond well to being watered in with comfrey liquid. They will also be given some mychorrhizal fungi to encourage symbiosis and, hopefully, better more fruitful plants.  

I went round for the Christmas harvest today and this is what I took home for Christmas dinners:

1. Curly kale
2. Purple sprouting broccoli
3. Brussel sprouts
4. Winter cabbage
5. Parsnips
6. Carrots
7. Leeks
8. Onions - from the store shed.
9. The last squash in the store shed.  All my butternut squash have rotted away.  
10. Elephant garlic from the store shed
11. Ordinary garlic from the store shed
12. Shallots from the store shed
13. Beetroot
14. Salsify
15. Hamburg parsley
16. Swede
17. Kohlrabi
18. Red Duke of York potatoes from the store shed.   

I think that I might just have enough veg for Christmas dinner.  What is left will make soup for the rest of the week.