Due to the encouraging results last year, both as a crop and as a system's autonomy, but also as an appreciation of the readers of instructables
(https://www.instructables.com/id/Self-watering-vertical-garden-with-recycled-water-/), i decided to equip new planters also on the first floor of the building close to the original set-up.
Having collected enough 18l water bottles (thanks Ricky), i started to draw a model with sketchup to get an estimate of the materials and tools needed for the project.
Aim of this project:
-autonomy and low maintenance after the initial set up, the system should be automatic (the place is away from home and I can not check every day and also i'm often out of my country for work)
-Green design: wood, jute and felt are recyclable and biodegradable materials and parts, rubber and plastic are also recyclable. The bottles are already recycled.
-Green-power: the system is supported by a wind generator and a solar panel with its battery.
-Organic gardening is the main purpose, therefore they are not used chemical fertilizers.
Fertilization will be done through the introduction of fish and aquatic organisms in the water tank as in aquaponics systems where organic matter produced by the fish is processed by bacteria that make it assimilable by plants in a closed loop.
Step 1: FRAME
The planters were made as in the last year's set and are composed of 18 l plastic water bottles, cut and flipped on wooden shelves suitably perforated to allow the bottleneck to fit stably. The original cap is used together with a piece of water hose to create a small reservoir of water into the bottle. This configuration allows each planter to have a small water reservoir that let the plants to survive 1-2 days in case of failure of the system of watering.
(see my other instructables for details)
Each planter is then filled to 1/4 of the volume of expanded clay on which is laid a sack of felt filled with soil. The use of these bags allows drainage and aeration of the soil and does not permit the soil to mix the with clay.
The bottle is externally coated with jute to protect plastic and roots from the sun's rays.
Step 2: Water Circulation
I drilled 4mm holes in the drip pipes to permit pass throught water and bigger holes in the collecting pipe accommodate the bottlenecks. Some connections between pipes are made with water hoses.
three pumps take water from the filter that is connected to the fish tank, the other from rain barrels placed on the east side of the building. In this way, i try to compensate for the water lost to evapo-transpiration, soil absorption and any little losses of the circulation , without having to refill it manually.
In the south side, after crossing the planters, the excess water is collected and conveyed to the drip pipe below and from there through the planters arrive in the fish tank. In the west side, after passing through 2 rows of stacked planters, water flows through "the green window" of sedum plants and then passes into the main collecting pipe and in the fish tank. After passing into the bio filter, the water begins a new cycle.
Step 3: Fish Tank and Filter
The barrel filter is made with several layers of coconut fiber and felt and a layer of expanded clay.
After a few weeks, in the bio filter will establish a community of bacteria capable of transforming the ammmonia produced by the fish into compounds assimilable by plants.
The varieties of fish that I have chosen are carp and catfish for the fish tank and Gambusia to the rain barrel.
The gambusia is a small fish of about 5cm which has the distinction of being particularly voracious of mosquito larvae and thus useful in my project (I live in an area where in the summer there are lots of mosquitoes).
To oxygenate the water I put the air stones in the fish tank and the biofilter and I connected to a small cheap compressor 12vdc and i added a circulating pump.
Step 4: Power
Two different circuits are powered by the battery:
The first consists of 4 water pumps regulated by timer 12vdc (at this moment 3 minutes at 6 am an 3 at 6 pm ), the second is composed by a 12vdc tire air compressor and an another pump to recirculate the water in the fish tank , both regulated by a different timer ( at this moment 4 minutes every hour).
I started to test with different timing to understand how many power can use the system , in case I'll decide to switch to real aquaponics That need more watering cycle and more power .
At last a power inverter is connected to the battery that allows me to recharge my laptop and use tools.
Step 5: Start Growing
If I have time next week I'll get the fish. will post some updates soon.
Step 6: April Update 1
Were added as anticipated some fish to complete the setup five little goldfish and six Gambusia affinis (aka mosquito fish) .
For more differentiated ecosystem I added Lemna minor (common duckweed ) , a floating plant , taken at a nearby irrigation canal and some water snails (Lymnaea stagnalis)
The fish are set well and duckweed began to grow rapidly.
Step 7: April Update 2
The pumps for car tires will not last long with daily use for the air stones therefore I decided to use another system, perhaps less powerful but quieter and less energy consuming especially .
Now I have two pumps connected in series to the air 6VDC bought from ebay , I added a fuse and non-return valves . It is now about a month that works perfectly.
Step 8: April Update 3
The salad at the moment has already been collected divese , cutting above the root to allow regrowth.