Never have you seen a more satisfied group of people than our cohousing residents yesterday after a day of working together to regroup after the summer and prepare for winter.
Last week we walked around our 8.5 acre site together and prepared a list of jobs. Some are urgent, some not so, and some will continue to bounce along in and out of the long grass. With this list in mind, yesterday people put their different skills into action…
- Barley straw added in to treat non-potable water reservoir
- Chicken shed moved
- Angle grinding of an old axle to prepare for recycling
- Hotbox composter emptied and refilled
- Pallets in place ready to construct into new compost bins
- Donkey manure ready to mulch
- Digging of beds (couch grass means no-dig methods are no go so far)
- Sheep sorted into different paddocks, ready for the ram later in the year
- Hay moved to winter storage
Shared space means shared responsibility
The definition of cohousing is that there is an element of shared space. At Hockerton Housing Project each household owns its own house and garden, but with that comes the benefit of shared access to 8.5 acres land, income from the onsite business and the use of facilities including renewable energy systems and various ponds and lakes. Not forgetting the zip wire, treehouse and pizza oven! To manage all this, each house has a commitment, set out in the original planning permission and bound in a 999 year lease, to undertake a certain amount of hours work on the Project. Visitors on our tours are often taken aback by the idea of such a formal commitment but, as the work is flexible in terms of content and timing, it quickly becomes a way of life.
Flexible working
Some of the work is paid, where undertaken for our trading business, and the rest is compensated by a supply of fruit, vegetables, eggs, meat and access to the land. All of it is tracked so we all do our fair share. Those working full-time elsewhere may take on the weekend jobs of public tours or evening jobs of managing the website and tour administration. Others may have ideas that they can develop as part of the business: our current projects include R&D for a new form of renewable energy generation with a local university, building performance monitoring on behalf of a housing association, asset management of wind turbines for community energy groups and farmers, and our ongoing range of tours and workshops to develop sustainability knowledge and skills.
Such flexibility, and a decent pay rate, means it can work well for people of all ages, including those who want to cut back on full-time work. The activities suit a range of interests and personalities, and stages of life such as those in the early days of retirement or people who want to continue working whilst also caring for young children, and for those looking to develop new skills, or apply existing ones, in the field of sustainability.
Where there is a will…
The need to cooperate underpins this cohousing approach to managing shared land and a shared business. Plans need to reflect shared needs and values, whilst also taking into account individuals’ skills, time and interests. If people had neither the time nor the inclination to act, the business or use of the land would not develop as intended. But where there’s a will, there’s a way. And there’s definitely a Hockerton will, and way, to develop… sustainably of course.
Last year we embarked on a trial of aquaponics in a domestic setting, as part of a PhD undertaken by John Grant of Sheffield Hallam University. Our related blogs are not a guide in themselves, but perhaps help fill some of the gaps we found in existing literature. If you want an introductory guide we recommend Sylvia Bernstein’s Aquaponic Gardening.
This blog follows up on our previous post with a review of our first 6 weeks of hosting fish, and the snags we had with our initial build. There was a gap of some months as having built the physical system we were nervous of the temperatures that could be reached in our polytunnel and so waited until the summer so we could monitor temperatures before introducing fish to the system.
The build
Our first visit to the polytunnel after the winter break was a bit of a shock, as the foundations for the water tank had subsided. This meant we had to empty the water tank and dig out the earth around the sump tank to the extent that we could embed boards to stop the earth from collapsing against the tank.
Lesson learnt: if placing the fish tank over an IBC sump tank, box in the sump tank – however firm you think the ground is. We’d also suggest that the top water tank is filled some time before adding fish, if you are not building on a very firm base. The fix for our problem would have been a lot harder if we had already put fish into the top tank, and very disheartening if cycling had already started.
Having plumbed the growing beds’ inlets and outlets we added water to check the autosipons worked. It is worth doing this without the clay balls in place. We also discovered a leak in one of the tanks at this point.
Lesson learnt: It is much easier to fix these things before the clay balls are added.
Down the track we have realised that it will be difficult for us to alter the height of the outlet pipe that sits up in the tank. Ours is a single piece of pipe down to the junction with the outlet pipe that returns to the sump tank.
Lesson learnt: Plumb the system so that the pipe within the tank can be removed.
We have also realised that whilst we take water from close to the top of the fish tank, this can still carry a fair amount of gunk (technical term). It is likely that this affects the water flow.
Lesson learnt: Install a settling tank in the plumbing immediately after the fish tank.
Which fish?
Originally we had hoped to stock Tilapia or trout, but were concerned about the need to heat or cool the tanks. Having reviewed various guides it became clear that carp were one of the most robust fish when it comes to temperature range and fluctuations. And, as we have a lake full of carp on our doorstep, carp it was. We don’t normally eat carp because it is very muddy when fished from the lake, but we realised that keeping it in the aquaponics fish tank offers a way of cleaning out their systems,and perhaps make them more appetising.
We spent a significant amount of time trying to source organic fish food but it seems to be available solely to large scale fish farms. The first batch was a floating feed from a local ‘World of Water‘, which we have followed up with a slow sinking feed for coarse fish from Skretting. We are also considering how we can farm duckfeed as a high-protein green for them.
Lesson learnt: We recommend a floating feed. Whilst carp are, naturally, bottom-feeders, they were happy eating from t
he surface after 1-2 days, and this gives you a chance to check on them.
Whilst considering the animal kingdom, it is worth noting that we found a frog in the sump tank one day. It is worth ensuring that the tank is sealed, and/or providing a route out for anything that decides to go for a swim.
Cycling the system
We used the Murray- Hallam cycling technique to start the system off. This means adding liquid seaweed and adding plants, and then waiting for 2 weeks before adding fish. There was concern about the pH of the water, which was higher than the ‘ideal’ range given in the literature. However, having tested the pH of the lake from which the fish would be taken, we realised they were the same, so no action was taken on its acidity. This has dropped over time.
We were also able to introduce some rocks from the lake into the growing beds. They carry ‘healthy bacteria’ that would help speed up the cycling process.
3 solar powered oxygenators were used over the summer, which are now powered by the mains as daylight hours start to reduce. We cannot currently monitor oxygen levels in the water, but hope to get a more efficient approach to the energy consumption in future.
The rationale for this approach was that the water would be prepared for the fish. However, 2 weeks into their residence we found a number dead. This hit us hard as the whole idea of this approach had been to avoid stressing the fish. It appears to have happened because the stocking levels were too high, and they received more food than necessary due to some enthusiastic helpers. We reduced the fish levels to a quarter of that suggested in the literature, and their feed is also given at a lower rate than suggested. A month on the pH, Ammonia, Nitrite and Nitrate levels remain spot on.
Lesson learnt: Use the Murray-Hallam method but introduce the fish very gradually, and give a single person responsibility for feeding. It is better to lose some early plants than put the fish through stress.
Data monitoring
We are yet to start the formal monitoring of the system but readings were taken daily during cycling and the first two weeks of the fish residency. Now the system is up to speed we are testing pH, ammonia, nitrite and nitrate levels on a weekly basis. We found (but don’t know if this is the norm) that the Nitrite level rose and fell very quickly, and the Nitrate level rose to 80ppm on the day after the fish were introduced and haven’t fallen much since.
We also visually check the water levels and flow rates in the tanks and from the outlets into the grow beds. We have found that we have to add around 300 litres of water on a fortnightly basis over the summer, suggesting that evaporation is more of an issue than we expected.
Our greatest concern is the temperature, as this is very difficult to control, and there is no data available on this for our particular site (a polytunnel in the UK). The good news is that the water appears to limit temperature swings with its highest temperatures on the hottest days reaching 5 degrees less than the outside air, and staying 5 degrees warmer than the outside air overnight. It is likely that the water will provide a similar cushioning effect over winter, and it is hoped we will have full temperature monitoring to provide more information to protect our fish, and help others with their aquaponics plans.
Output!
First plants go in, and visibly struggle to find nutrients
The planting of the grow beds was circumstantial rather than planned. A tomato cutting or two have taken hold surprisingly quickly and are now fruiting. Some supermarket coriander plants thrived for around 6 weeks but didn’t survive the first cold night of the autumn, whilst some strawberry plants surprisingly fruited within weeks. Spare pea seedlings grew, but failed to fruit. And of the greens, the lettuces have taken well but various brassicas have been eaten by unseen bugs (or slugs?).
At this point it seems that the output is different to that achieved in soil. Some leaves, like spinach and mizuna, are growing well and deliver on taste and texture; but other lettuces are just too limp. Next year we will need to more consciously trial what works and what doesn’t.
And finally, perhaps most exciting for a beginner, that thing where people just scatter seeds into the grow beds – it works! In early August, in a rush before going on holiday, I sprinkled a handful of dwarf peas into the bed and covered it with a single layer of clay balls. Those plants are now growing nicely and producing flowers. Light levels may now be too low to deliver many peas this year, but they may well survive the winter ready to grow on in the Spring.
We have cut the cost of our public tours that we host six times a year to our ecohomes. This is thanks to an EnviroGrant for £990 from Veolia (Nottinghamshire County Council’s waste contractors),
The tours are a unique opportunity to visit a co-housing development that has shown zero carbon housing is not only possible, but also desirable. A resident takes visitors on a walk around the 15 acre site to look at how we manage our needs in terms of food, energy, water and transport. The highlight is a visit to one of the five private ecohomes on the development where you will see, and feel, the difference of the homes’ design. It uses the warmth of the sun and the fabric of the building to maintain a comfortable temperature year-round, whilst also maximising sunlight and providing flexible living space.
Tickets have been reduced to £5 for people outside the local area, and remain £2.50 for NG25 residents and free for our close neighbours in Hockerton. The next tour is on 4 November 2017. The fund will support tours up to September 2018, and places are limited so please book your place now.
The EnviroGrant Scheme is run by Veolia and offers a helping hand to a wide range of grassroots community, voluntary and grassroots projects. Over the years support has been granted for a range of projects such as providing outside classrooms, supporting forest schools, enabling recyclable material and updcycling workshops to take place, providing recycling bins at a youth centre; and assisting in the creation of numerous school gardens and biodiversity projects.
We remain on the lookout for ways to support schools and universities with the costs of visits, please let us know if you are aware of any such funding.
