Actively Aerated Compost Teas (AACT) – a mid summers spraying at Ragmans Lane

June 25, 2014 by The Urban Orchard Project Leave a comment

I recently spent five sunny days at one of my favourite places: Ragmans Farm (see previous post March 2013). I’d arranged to come and help with their annual spraying regime as the spraying regime at Ragmans isn’t your usual. Most commercial orchards, including those certified organic by the Soil Association, still rely heavily on routine applications of copper-based sprays as a fungicide against scab and powdery mildew, the former being the bane of the apple grower’s life. However, copper sprays or ‘Bordeaux mixture’ damages the delicate web of interactions that occur on the leaf surface and in the soil. And, as it builds up in the system, it can be harmful to fish, livestock and earthworms.

In his usual humble manner, Matt, the farm manager, told me “we’re not claiming to be experts on this and it’s still pretty experimental”. At Ragmans the preferred term is ‘beyond organic’, as Matt says “we need to get out of the habit of thinking antibiotically – ie spraying against pests and disease. We need to approach our orchards in a holistic, probiotic way. We need to strengthen the existing beneficial micro organisms and insects to produce food free from residues”.

So, enter the wonderful world of Actively Aerated Compost Tea (AACT). This wonderful brew is essentially a living liquid soil food web which is sprayed onto the canopy, trunk and surrounding soil of the tree, inoculating it with a micro-herd of beneficial organisms. The key word here is aerated; AACT is not to be confused with your pungent smelling, anaerobic comfrey or nettle teas which are usually applied to the soil only. AACT’s are brewed by bubbling air through a solution containing compost containing ‘seed’ micro organisms. During this brewing process these tiny organisms will reproduce rapidly.

By using different types of compost and additions, the tea can be nurtured to make it more bacterially or fungally dominant, depending on what type of plant you’re spraying. As fruit trees prefer a fungally dominated soil, as they originate from a forest-edge ecology, the order of the day here is a fungal-heavy brew, although it’ll also be teeming with bacteria, protozoa and nematodes. Choosing the right type of compost to start with is key here, with a mature compost being a more fungal one.

Pete had started the brew a few days before my arrival, based on one of Soil scientist Dr Elaine Ingham’s ‘recipes’. This involved suspending a mesh bag of mature compost in a barrel filled with spring water which runs down from the hills at the farm, tap water being unsuitable due to the presence of chlorimines which kill the fungi. “The council here started using chloromines instead of chlorine which means you can’t even leave it 24hours to evaporate off” Pete told me. Some forest soil and leaves from the apples trees are added, to inoculate the mix with the microbes already present and adapted to both the soil and phyllosphere (the above ground part of a plant as microorganism habitat).

To get the fungi off to a head start, they’re offered a tantalising platter of seaweed, yeast extract, organic molasses and porridge oats. The organic choice is important; not because the fungi are fussy feeders, but because of the presence of preservatives in so much of our conventionally produced foods these days, which exist to destroy the fungi, not nurture it.
Vitally, the brew is aerated using a pond aeration pump and stones, for 2-3 days, in a cool place. Adequate aeration is critical and the water should look like it is at a rolling boil. The organisms must be active and growing to be producing the ‘glues’ or exudates required for them to stick to the tree surface. Without the aeration the mixture would quickly become anaerobic, and the beneficial microbes would die and be replaced by anaerobic bacteria and root-feeding nematodes and potentially harmful pathogens such as e.coli.

And then comes the spraying. Pete demonstrated using a lance spray, tank and battery powered pump. After re-acquainting myself with my old friend Dumpy (the little 4×4 tractor) I got to work giving each tree a healthy soaking, following the branches to the tips and back down to the trunk and importantly to the soil. Each droplet of the AACT contains a wide variety of microbes as they derived from a few handfuls of compost made on the farm from leaves, twigs, roots, shoots and the odd handful of garden soil. When a droplet lands on the tip of a leaf the microbes within that droplet that are evolved to work at leaf tips are activated and get to work protecting the leaf surface. Other microbes ‘switch off’. Conversely droplets hitting the ground will favour soil dwelling microbes that will then multiply to inoculate the soil.


These favoured microbes waste no time in munching other less favoured ones. As they increase in number they form a ‘thatch’, surrounding the leaf cuticle or root. A carefree rust spore floating on the wind will alight onto the leaf hoping to penetrate its unprotected cuticle. Instead it lands in the soup of microorganisms surrounding the leaf and is broken down by bacteria looking for a protein-rich fix.

 It’s an unforgiving microbe eat microbe world down there at the microscopic level. “This is the beauty of homemade aerated compost tea – the ingredients are readily available and you are simply strengthening the resilience of your system” said Matt.

It can take up to 30 minutes for the fungi to attach themselves to the tree surface, so it’s important to spray on the shady side of the tree if it’s sunny, so that it doesn’t dry too quickly (the soil microorganisms are also sensitive to UV).

And so I spent several happy days working my way along 1000 trees, intermittently returning to the barrel to refill the tank. This was the first time I’d visited in mid summer, so it was treat to witness the farm and its surroundings in full lush mode. The blackbirds and warblers sang by day (well, until I started up Dumpy’s engine) and the owls called through the night. It was nice to not have to worry about personal protective safety equipment (as the impromptu video in this blog shows); one can take a laissez faire approach to safety when using such a spray. And, as I’d frequently get covered by a fine mist of the stuff, I was thankful that it didn’t smell bad – had it been comfrey or nettle tea I’d have smelt like a sewer for weeks. However, I was grateful for my sunglasses; not even the most enthusiastic proponents of the soil food web desires a case of the ol’ nematode in the tearduct.

video link here

During the evenings I hung out around the fire with the latest permaculture students on Patrick Whitefield’s course, drinking cider made from the very trees I’d been spraying, and I gave a talk about how the Urban Orchard Project are applying permaculture principles to our work. On my last evening I went to watch England take one step closer to World Cup exit curtousey of Uraguay with the lovely crew at Ragmans Lane Market Garden: four inspiring young growers selling organic produce to pubs and restaurants around the Forest of Dean.

Once again it was time to head back to the capital, something I always find hard to do after a few days at Ragmans (and one too many ciders the night before). I look forward to returning in October for some cider-related happenings.

Thanks to the Ragman’s crew for the opportunity to take part in the spraying, the PDC group for their hospitality and enthusiasm, Cari for lending me her hat, Andy his camera and Steven for the impromptu photo and film shoot.

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Future Farmers at Ragmans

Have a look at this great blog post from the  Sustainable Food Trust newsletter about the Growers at Ragmans Lane Market Garden. The growers have their own blog too, you can read their blog here.

My Experience of Making Apple Juice at Ragmans

By Chris Klasinski

Here is a relatively short account of my time working at Ragmans Farm picking and processing the apple harvest which is primarily used to create high quality organic juice. I have given some thoughts and experiences from each of the three main stages of production.

Picking:

The orchards at Ragmans contain a huge variety of different apple trees. Over 30 apple varieties are grown for juice and another 10 pear and cider apple varieties can be found here too. This gives plenty of benefits through diversity but means finding the type of apples that are ripe and required to create a particular flavour of juice can be a bit of a challenge. 

Armed with maps of the orchards and riding around on Dumpy, a mini 4x4 pickup/tractor type vehicle, we fill sacks and large wooden boxes with wonderful chemical free apples ready to be taken

to the refrigerated shipping container where they will wait for the next stage on their journey to becoming a fine bottle of pure fruit juice. 

The only spraying that is done here is with Aerated Compost Tea which is designed to inoculate the trees with all the beneficial microbiology that is found in good compost. Essentially it boosts the immune system of the tree as this friendly microbiology competes with the unfriendly ones.

By creating a liquid spray only a very small amount of solid compost is needed compared to the enormous amount of solid compost that would be required to spread on the soil around each tree. As Pete the senior farm worker at Ragmans explains to the students on the Permaculture Design Course: “We do still get diseases in the orchard but it’s a balance of diseases, with none becoming dominant and posing a real problem.”

The use of Aerated Compost Tea is an experiment which only time will reveal to be a success or not. So far the results are promising and I think the apples taste great.

Occasionally whilst out picking in the orchard there is a moment to take in the beautiful views of the farm and the surrounding land. This is a time when I am thankful to be working in Mother Nature’s office rather than the brick boxes I have been enclosed in so many times before. Even after frantically picking Bramleys amidst a jungle of stinging nettles during the pouring rain I felt better than I ever did coming home from a day working in a call centre. After all, being stung by stinging nettles is good for your blood circulation and it was a beautiful moment of contrast to see the sun come out just as we were finishing.

Most of the time out in the orchards is spent filling sack after sack then lifting them into and out of Dumpy which in my view is a far more productive workout than I could ever get at a gym.

This year the harvest has been a lot better than the previous year. However the constant rain, and the resulting water logging of the soil, last year has almost certainly caused damage to the roots of many trees. This means some of the energy they would have used for fruit production will have instead been used to re-establish their root systems. Hopefully next year they’ll be fighting fit again and able to concentrate on the delicious gifts they produce.

As part of my increasing desire to experience the world around me with a deeper sense of connection I have been apologising to some the trees for the rough treatment when a little shaking is required and also thanking them for what they give to us. I view the trees here as my equals and I think it’s important to recognise the hard work that they do all year round to give us the apples that we take to The Juice Shed. Thank you trees!

Pressing:

The Juice Shed is where all the processing of apples (and pears, raspberries and blackcurrants for the blends) into juice is done. This happens in two stages, the first of which is to clean the apples in a large tank of water. Then they are loaded, by hand, into a mill. This machine is much like a wood chipper that turns whole apples into a pulp that can be loaded into the press where it is squashed until the juice has been squeezed out and pumped away through a filter into a large container.

In contrast to the peaceful open surroundings of the orchards this stage of the process is confined to a small and rather noisy space, but still outside in the fresh air. The combined sounds created by the mill, the press and the

pump mean verbal communication has to be shouted and hand signals and gestures are often more effective.

This is a bit of a messy job, especially when hurriedly emptying the dry pulp into large builder’s sacks quickly enough so the cloths that contain the pulp can be used for the next round of pressing. This is when I have received a lot of unwanted attention from the local wasp population, who perhaps feel that we are simply putting on a party for them. I’ve only been stung once but have had our yellow and black friends flying at my face and trying to land on me many times. This has had the welcome effect of making me a lot less bothered about being around them – although I still prefer to keep a healthy amount of personal space between us.

Bottling and pasteurising:

Stage two in The Juice Shed is known to me as Bottle World. At this point the fresh juice from the pressing is pumped out of the large container through a filter and down into the two bottling machines where I have spent many hours shuffling between a pallet full of bottles and the six filling pipes. Early in the morning the bottles are cold, so are my hands and so is the juice. It makes for a slow start but pretty soon, as all warm up, I find myself getting into a rhythm where by my feet are moving in a sort of dance that carries me the shortest distance, back and forth, from the pallet to the machines.

The filled bottles are sealed with a cap and are then loaded into one of four hot water tanks that will

pasteurise the juice allowing it to be stored for many years. I always look forward to the first batch of bottles going into the tanks as the rush of hot steamy air that emerges is a delightful treat on a cold morning in Bottle World.

Once the juice is bottled and pasteurised it is laid to rest in a large crate where it awaits the chance to be labelled, packaged and sent off to be enjoyed by all the customers who buy this labour of love.

Some overall thoughts on my experience:

The last two months working the apple season at Ragmans Farm has involved some of the most physically challenging and demanding work I’ve ever done for a sustained length of time. Day after day, week after week I’ve crawled into bed each night to recharge my batteries just enough to get through the next day. The experience has certainly shown me my limitations and started me thinking how I would like to develop my strength and strengths both physically and mentally. It has also been some of the most rewarding and inspiring work I’ve ever done, an experience that I will never forget and have gained much from.

I am extremely grateful to all the people here at Ragmans who have given and shared with me this nourishing experience. I feel this place and the people who live and work here are an important part of the potential for a brighter future where we as a species can learn to live with the land and the rest of nature; A potential future where humans, once again, become a constructive part of nature and improve our own experience of life and reality. There needs to be more opportunities like the one I have been privileged to experience and I hope that I can find more next year after I’ve left Ragmans. I urge everyone to seek them out or create them if you can.

Chris Klasinski

For more information on the work at Ragmans Farm have a look at the following links:

Ragmans Farm

The Willow Bank

Juan-Fran’s Synergistic Agriculture Experiment

And for more information about Aerated Compost Tea I recommend the book ‘Teaming With Microbes’