Thursday, 11 June 2015

Tony's Permaculture Allotment.

This design focuses on a derelict allotment overgrown by perennial native flora and covered in builder’s rubble and rubbish.  An allotment is a small piece of land that can be rented from the local council in order to grow vegetables and fruit for the tenant and their family.  The tenancy agreements mean that there are many restrictions on the design.  Compromises have had to be made.  

Original state of the allotment. 

My aim is to reclaim the allotment for growing vegetables and fruit in one growing season by methods based on permaculture.  The allotment garden is situated at the top of the allotment site latitude 52o 35’ north and longitude 2o 11’ west. The nearest coast line is 80 miles to the west and 100 miles to the east. 
The climate is temperate maritime due to the effect of the Gulf Stream which ensures relatively mild weather and infrequent extremes for this latitude.  . 
The allotment site is on the western side of a big industrial conurbation which includes Wolverhampton and the village of Tettenhall.  Luckily, the prevailing winds are from the west so the allotment does not get wind borne pollution very often.  Very cold winds can often occur from the east.  These are winds blowing from continental Europe. 
The site is at the top of a hill 411 meters above sea level.  It is part of the West Midland plateau that stretches throughout the conurbation.    My allotment is at the highest point of the allotment site.  The source of the River Penk, a small brook, rises on the allotment site. The River Penk is a tributary of the River Trent which flows into the North Sea on the East side of the country.  On the other side of the hill Smestow brook flows south into the River Seven and the Irish Sea on the west.  
The allotment garden slopes very gently to the south. 
While the surrounding area is suburban, the allotment is fairly close to the countryside where the resources of farmyard and horse manure can be obtained.  Also, lawn mowings and shredded woody material are delivered frequently to the allotment where is it shared by allotment holders.
The soil is a gley with a clay and sand subsoil.  

The clay was deposited during the ice age by the Welsh glaciers and the sand comes from the underlying old red sandstone rock.  The soil has been depleted for decades by poor management.  Removal of top soil has resulted from people skimming off the top five centimetres of weed soil turf and disposing of it in refuse centres.  Also, crops seemed to have been harvested with little thought about replacing nutrients. Increasing the depth and fertility of top soil is a priority and will be undertaken by adding copious amounts of organic matter.

Allotment Zones.

Although this is a relatively small area, there are three identifiable zones within the allotment garden.

Zone 1 will be the main growing area for allotment. It is made up of raised beds in order to increase drainage, something that is necessary in this climate.  The raised beds will not be permanent and will be marked out by access alleyways to allow maximum flexibility.  The alleyways will be cut out 30 cm deep and the top soil added to the raised growing areas.  Shredded woody mulch will fill the alleyways.  This means that the width of the raised growing areas can be varied depending on the crop planted.  Rotation will mean that the crop will be changed each year so flexibility is paramount.  Although the raised growing areas will be flexible, there are  relatively permanent 60cm wide alleyways across the slope to allow access and to act as a mini swale.  Espaliered, cordon and fan trained top fruit and currant bushes have been planted on these swales in order to enhance the water retaining characteristics. The zone one area of the allotment is about 1/10 of an acre or 404 m2.  (5 perches by 4 perches). The orchard, zone two area, is about 110 m2.

Zone 2 will be a standard tree Orchard area.  This area will be scythed to reduce native flora cover and trees planted with minimum soil disturbance. 

Zone 3 the hawthorn hedge.

Surface Water Management.

Although tap water is piped to the allotment site, water conservation is a priority.  Hose pipes are banned except to fill water butts.  All structures should have gutters to collect rain water and this should be stored in water butts. 

Further water conservation techniques would be valuable in maintaining reasonable water usage.  Due to the number of days each month that it rains, with proper water management, there should be little need to irrigate the outdoor growing beds.  However, there are two greenhouses planned for the site and these will need to be watered.  Hopefully, the rain water butts will be able to provide most of this water. 

There are several hard surface areas to the north of the allotment including a car park, track ways and paths.  A drainage ditch dug alongside the zone 1 growing area and the hard surface car park and track way would allow capture of surface run off and slow soakage into the growing area. 

The slight slope to the south means that any nutrients produced and leached at the north end of the allotment will slowly infiltrate the allotment soil.  The compost bay will be sited here because of the easy access from the car park.  As this site is within an urban area, I will have to rely on imported organic matter to supplement the compost that I can make from the allotment itself.  Also run off from the compost area will run into the allotment soil. 

Zone 1 gardens do not lend themselves to large swales, however alleyways between the growing beds can be taken out 200mm deep and the soil put onto the growing areas to further raise the surface and provide a deeper top soil growing media.  The alleyways can then be filled with woody shreddings mulch and used as footpaths to give access to raised beds.  The alleyways will allow soakage of water into the raised beds when there is excessive rain.  The main 2 foot wide alleyways are more like mini swales and provide raised mounds planted with a range of fruiting trees and bushes.  The roots of these plants will further retard the surface run off and facilitate soakage.  As all these trees and bushes are in a zone 1 garden they will be espaliered or fan trained.  The Rubus fruiticosus, Rubus phoenicolasius and Rubus x loganobaccus canes will be tied to a frame.  This will mean that both top and soft fruit plants will not intrude into or heavily shade growing areas.
In this design, it would be pointless to make the beds curve or bend because the gentle slope to the south is fairly uniform.  The 410 metre contour line makes a U shaped intrusion into the bottom of the allotment.  Also, as the graph below indicates, in the British climate, water is not usually a limiting factor whereas light and heat is.  Roughly a third of each month has rainfall and this extends throughout the year. 

To facilitate both drainage and infiltration of water the paths have been designed to store and drain water from the growing area. 
All the paths were laid on top soil and this is a waste of a valuable resource.  The paths have been dug out and the top soil sieved and put onto the growing areas.  The foundations of the path will be builder’s rubble and stone sieved from the top soil.  Carpet found on the allotment will prevent clay and subsoil from falling between the rubble. A layer of clay on the top will facilitate levelling, increase the thermal mass of the path and suppress unwanted plants from growing between the slabs.  

This will give an ideal habitat for Mentha species to grow between the slabs and the curbing.  Alongside the path, herbs can be planted in order to benefit from reflected light, increased thermal mass and water soakage from the path sump. 

Tenancy restrictions mean that these ditches cannot be dug on contour; however the gentle slope towards the south allows maximum water harvest while remaining within the restrictions of the tenancy agreement.  Although the trackway is overgrown, any modification must reinstate the original trackway.  The ditches will be filled with stone and rubble sieved from the growing area tops soil.  Similar ditches will be dug to harvest hard surface run off from the car park. 

Topsoil dug from the drainage ditches will be sieved and put onto growing areas to make raised areas for tree and legume planting.  Along the north boundary Laburnum anagyroides,  Cytisus scopaius, Lupinus x hybridus, and Trifolium pratense will be planted on the raised area which will be the highest point on the allotment.  These plants will produce some organic nitrogen which may infiltrate the soil with the flow of water down the slope. The laburnum trees will be espaliered to produce a wind break against north and north west winter winds.

The hedge alongside the road must be maintained according to the tenancy; however it will be managed as zone 3 hedge – with minimum intervention.  The hedge does have some Rubus fruiticosus within it but more will be planted.  Also  Allium ursinum, Symphytum officinale, galanthus nivalis, calystegia sepium, Urtica dioica, Myrrhis odorata and Hyacinthoides non-scripta will be encouraged to grow.  Alongside the hedge there is a path and the top soil from under this path will be removed, sieved and put on the growing areas.  Stone and rubble sieved from the top soil will be used to make a foundation for the path.  The path will then serve as a drainage area. Furthermore, some water will be retained by the hedge bank allowing soakage in the growing area.  The path will be alongside a long row of Rubus ideaus which will allow easy harvesting without treading on the growing areas.  The bank and hedge will prevent pollution from the road reaching the growing areas.  The Rubus ideaus will aid in this screening effect. 

Cross section of hedge bank and path.

Cross section of small shed and foundations. 
Growing bed orientationTop soil will be removed from beneath the sheds and greenhouses in order to preserve it and use it on growing beds.  Builder’s rubble and stones sieved from the top soil of the growing areas will be used to make foundations for these structures.  This will achieve several functions.  This will act as a sump and water storage, will allow water to infiltrate through soil slowly and will also increase solar thermal mass storage under the structures.  The sheds will be used to store vegetables such as potatoes and onions during the winter and increased solar thermal mass storage will help to keep the sheds frost free.  The greenhouse will benefit from warmer temperatures particularly in colder months of the year. 
The guttering of the small shed extends over the water butt so that the down pipe can reach the bosh.  This means that I could attach a bird feeder to the gutter over the butt.  Any bird manure that is produced will fall directly into the stored water.

Planning around the greenhouse area.
In a similar way the main greenhouse will have increased solar thermal mass in order to maintain an even, low level heat in the greenhouse. The greenhouse has been sited to obtain the maximum amount of light and heat throughout the year.  As you can see from the chart below,  the sun is very low in the sky during the winter so greenhouses need to be sited where there is little shading from buildings or trees.  Deciduous trees are more of a problem in the summer when they are in full leaf.
In summer the sun is high in the sky above buildings for most of the daylight time.  The time that the sun is above the horizon lengthens considerably from December to June and this means that greenhouses, sited for maximum winter light, can get very hot unless they are shaded using a white wash on the windows.  (Days do not get longer in the summer - they are 24 hours more of less, throughout the year.)

Section through the greenhouse and foundations.
At a latitude of 520 north which is the same latitude as Nova Scotia and southern Siberia, the outdoor growing season is at most six months.  Although the graph of annual number of days of frost for each month is a little pessimistic, we cannot reasonably sow or plant outside until the second week of April, while the first frosts usually return in October.  Any technique that ameliorates the cold temperatures during the year has to be employed and orienting beds north south will facilitate greater exposure to sunlight and heat particularly in April and November allowing a slightly extended growing season.

The allotment site is about 80 miles from the Welsh coast from where the prevailing winds come from. However, there are some relatively high mountains in Wales between the allotment site and the coast of Wales producing a slight rain shadow effect.  Regardless, a reasonable amount of water can be collected from the roofs of all the structures and stored in water butts. 

Peach Green House and Cold Frame.
Both of these structures have the top soil removed and replaced with shredded woody material. In Victorian time they used something called tan.  This was the waste material from the leather tanning industry.  It was the remains of shredded bark.  The Dutch found that it was a very good substitute for manure in hot beds.  The shredded woody material heats up and retains it heat for longer than manure. 

I will use this material to make hot beds both in the cold frame and the peach house.  So instead of a banana circle I will have a peach rectangle.   Peaches are hardy enough to grow outside in England, however they are vulnerable to late frosts and a disease called peach leaf curl.  Both of these problems can be alleviated by putting the tree in a greenhouse for protection.  During the summer the greenhouse door will be left open.  While most of the greenhouse top soil has been dug out the area where the peach is to be planted has been left so that the peach tree can be planted in soil.  About 1 meter deep of soil has been removed. The best soil will be put onto the growing beds while the clay subsoil will be used on the paths.  The surrounding growing beds are higher than the floor of the greenhouse so there is net flow of water into the woody mulch keeping it damp.  This will reduce the amount of watering the peach tree needs.  There is enough room in the greenhouse to grow 8 ring culture tomatoes.  The rings will be placed directly on the woody mulch and filled with homemade compost.  The tomatoes will be grown up strings attached to wires strung across the eves of the greenhouse.  When the peach gets bigger this will be less of an option.

Peach house on the allotment plan caption
 Cross section and plan of peach house.

Fruit in the Zone One garden.

Except for the dwarf standard apple tree which was already on the allotment, all the apples are grafted onto M26 rootstock in order to create a 4 or 5 layered espalier.  All trees and bushes are planted with mychorrhiza fungi to encourage establishment.  Most of the apple trees are heritage varieties, some of which are quite rare. These include Pitmaston Pineapple, an apple that originated in the West Midlands.
The fruit trees will be planted on the soil taken out of the larger more permanent alleyways cut out at right angle to the slope.  The soil will be used to raise the fruit planting areas.   This will help to increase surface rainwater capture and allow soakage. 
Espaliers on the eastern side of the allotment will reduce cold east and north easterly winds.  Although they are deciduous they will still have a wind calming effect during the winter.  Only the cover crops such as grazing rye and tares will be growing during the winter so there is less need for a massively effective wind break.  
The two grape plants are pruned to the double guyot system in order to make sure the vines do not overly shade the growing areas.  They are orientated north south in order to make the most of the sunlight reaching them throughout the daylight time.  They are planted on a raised bed produced by taking out a 60 cm. wide alleyway parallel to the slope. 

Fruit in the Zone Two Orchard.

I will be using mainly heritage varieties of top fruit.  Tettenhall Dick is a pear that was bred in local area. It is a very hard pear and is only useful for making perry.  Berry bushes will be planted under the top fruit and these will mainly be blackcurrant and gooseberry. The understory will be mainly native flora also used as a chop and drop mulch for the top fruit and berry bushes. 
The trees and bushes will be planted into original soil with no major tilling.  The ground will be disturbed to plant the trees and well rotted compost will be added to the planting holes.  Mychorrhiza fungi will be put into each of the planting holes.  A wide area around the trees will be mulched with shredded woody material to a depth of 4 or 5 cm.  (The trees have just been grafted on to M26 rootstock and are not big enough for deeper mulch.) 
The original understory of wildflowers will be retained and supplemented with further plantings particularly of Symphytum officinale which I use extensively as a soil amendment. 
Zone 1 Growing Beds.
Having used Hugelkultur beds for many years, I want to apply it to the new allotment growing area.  I have used Hugelkultur to raise beds and to regulate the mass flow of water through the subsoil.  I used it mainly as a drainage method.  As the method seemed so good for raising beds and providing a sponge like layer that helps to regulate water flow, I thought why not use it to raise the whole allotment?  The soil could be raised even further when the alleyways are cut out. Furthermore, without boxing the beds in with wooden borders, these raised areas and their alleyways could be temporary features that allow flexibility when moving vegetables from area to area.  Raised beds could be widened or narrowed depending upon the nature of the vegetables growing there rather than the whims and fancies of woodwork.   
 If trenches were taken out perpendicular to the slope then a primitive water control method could be devised that meant that water would have to negotiate clay sand subsoil ridges.  Also subsoil and clay could be mined for the paths and foundations. Furthermore if the top soil was sieved, stones could also be mined for paths and foundations.  While top soil was being sieved powdered manures, rock dust and manures could be mixed throughout the soil profile. 

The idea of burying large amounts of woody material is to regulate mass flow of water through the subsoil.  Water will tend to collect in the depressions and soak the wood.  When there is excess water the depressions will fill and there will be net flow at right angles to contour.  However, the mixture of woody shreddings and subsoil will further slow the movement and allow soakage and access by plant roots.  When there is a lack of rainfall the woody material will still retain water within the subsoil allowing some passage into top soil by capillary action. 
The extremely slow anaerobic decomposition of the organic matter means that there is little methane production and what is produced will be quickly utilised by methanotroph bacteria and archaea which are ubiquitous throughout the soil profile. 
The increased cation exchange capacity of the soil with added organic matter will allow nutrient capture and release as top soil manures and mulches decompose. 
The system will be fairly flexible because I can alter raised beds and move alleyways without having to dismantle woodwork. 
Once the garden has been raised by trench Hugelkultur the system will be in place for several years before the wood rots away completely allowing a no dig system to be employed for many years.  As the wood rots it forms a very friable growing medium, extending a rich carbon full top soil further down the soil profile. 
The system is based on the indigenous South American raised beds where brushwood was used to raise soil above marshy areas.    
This is a system that will work in the cool humid temperate climate of the UK.
Soil erosion will be greatly reduced because slow water movement will facilitate deposition of silt, clay and organic particles.  Furthermore, decomposer bacteria and fungi in the hugekultur wood will extract nutrients that have been leached from the top soil preventing excessive loss.  While I am building soil from underneath, I am also building soil from the top by adding a thick layer of mulch on the growing areas. 
There are many good reasons for applying a thick 60mm to 100mm layer of mulch over the whole surface of the growing beds, prevention of evaporation from the soil surface only being one of them.   Shredded woody material initially has a very light colour and will reflect light onto the leaves of plants in the growing areas.  Eventually this colour darkens and the effect is lost, however, if mulch is applied in the spring, the temperature and light levels would have improved greatly by the time of colour change.    As Bill Mollison says, mulches also enhances the ethylene/oxygen cycle necessary for good soil health.   
The zone 1 garden will be rotated one bed each season anticlockwise around the main greenhouse.  No particular reason for this – just that it has to go some way or other. 
Rotation has many benefits; it allows us to plan for winter cover crops that will best enhance the next season’s crops.  Most of the growing areas will have a rye grass and tares winter cover crop, however where the peas and beans are going to be moved there will just be a rye grass cover. 
The rotation will also trigger an assessment of soil amendments reviewing the need for nutrient supplements such as lime and rock dust. 
After the initial Hugelkultur and raising of the allotment above the level of the surrounding land the soil will be thickly mulched with shredded woody material.  This material is imported to the allotments from the surrounding area and will be used to cover the allotment until cover crops are planted in the autumn.  Tilling will be reduced to the minimum – harvesting things like potatoes, roots and clearing brassica plants. 

Vegetables will be planted through the mulch and compost added to the planting holes.  Plants will be watered in using dilute comfrey liquid “tea”. 
As wide a range of annual and perennial vegetables as possible will be planted to increase the diversity of the plants in the Zone 1 garden, however members of various genus will be planted together.  i.e. Alliums, brassicas, potatoes, curbits and peas and beans.  This will allow suitable soil amendments to be added to areas as necessary.  For example; lime to the brassica beds.   
While this may be an unconventional subject for a permaculture system, the allotment seems to make a very good focus for design.  Too many allotment gardens are taken over without proper thought or consideration of the work and rewards that it can engender.  A permaculture plan enables you to consider new ideas and combinations that would not be thought of without it. It also suggest the ways in which work can be reduced considerably to allow focus on less strenuous activities. 
Consideration of mass flow of water that does not just focus on drainage is a major change in the way I consider growing.  Deliberation on the way nutrients move through the soil and the soil profile needs careful thought. 
While large scale earthworks are not recommended for zone one gardens, they are used for developing water management systems within permaculture.  I would argue that earthworks to drain and manage water in a zone one garden are also acceptable.  Moreover, doing the earthworks by hand rather than with machines means that it is very unlikely that this will be undertaken with any regularity, if ever again. 
This is a new adventure after giving up my allotment on another site after 33 years of growing vegetables.  The new allotment needed to be planned to get the allotment just the way I wanted and within a permaculture framework. 
I don’t know if I have achieved this but I have made a big effort to do so.  I know that the allotment is beginning to look very different from others on the site.  This is engendering a great deal of interest.

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