OK. I've just built a prototype wicking pot (50cm wide and 43cm high) using a biochar aquifer in the lower half of the pot and permafert in the upper half of the pot. The design is based on the Permachar Kitchen Garden (see on a separate page) which is a proven system - I just modded the irrigation element with a central water column using 2" PVC pipe with no separate horizontal overflow (used in most wicking systems) - the theory is, it won't need one. This is solid-state with no moving parts (other than water, soil biota eg.microbes, arthropods, fungi etc. and plant growth). Just a 4D matrix (x,y,z,t), where t stands for time. There is a 4D matrix in every piece of biochar as well as collectively within the whole design. The pot system will biodegrade over time but since the biochar has Millenia-scale C drawdown properties, the final design should be extremely stable over a long time. Adaptability and mitigation are key!
I siliconed the drain holes at the base of the pot and added slots around the circumference of the central 2" PVC pipe up to 10 cm above the biochar aquifer. The section of pipe above the slots can act as a reservoir for excess water eg.heavy rainfall/a water reserve over the warmer months. The wicking system should work like a 2-way valve. You could use a hose or 10 litre watering 'can' (most of them are plastic nowadays) with a detachable spray nozzle to fill the pipe until the water reaches 2/3 of the way up the pipe (or 1/3 below the top of the pipe). The watering times will be different for each (and also vary with the volume of the pot) so say around 30 seconds for a hose at average flow rate and 2-3 filled watering cans for a large terracotta/black plastic pot but this is just an approximation. The idea is not to waterlog the permafert but provide enough water for a few days of wicking or even longer which will depend on the rainfall/evaporation ratio too.
The pipe(s) could be capped in between watering to reduce evaporation from the aquifer.
If the pot is undercover, there will be no rainfall so the pot might need more regular watering. When the water level goes down to 1/4 of the way up in the pipe, it's time to top it up with more water since the aquifer (and permafert) is starting to dry out.
The biochar aquifer will store the water via biochar sucking it up and releasing it as needed, wicking the moisture up to the root zone of the plants where it's most needed. It also provides water filtration including the ability to remove salts, heavy metals and pesticides and herbicides.
Also, note that the biochar aquifer uses coarser grade biochar (small chunks eg.2-3cm diameter plus some smaller pieces to fill some of the gaps) and the permafert uses crushed biochar, which can be made in a large galvanised bucket and sledge hammer using a vertical pounding motion.
The straw lucerne will reduce evaporation, provide slow-release Nitrogen to the permafert and create a moister/slightly humid micro-climate for the plants above the surface.
I'm going to test it with perennial herbs, flowers and vegetables and immune building herbs to prepare our immune systems to fight COVID-19 and variants and whatever else comes our way, suited for the Mediterranean climate in which I live. The planting possibilities are endless...
Updates will be posted below...
I'm hoping to use a biochar-epoxy resin biocomposite (pioneered by Dr Mauro Giorcelli and his research team in Italy) to make pots and PVC pipe replacement (no drain holes in the pots). These would be non-toxic and organic (no microbeads). I'm also hoping to make the biochar with locally grown sea kelp (trace elements, minerals) for the Permafert and Pinus radiata (pine) for the aquifer in the Kon-Tiki 'Rolls'.
This could also test the biocomposite for Mediterranean conditions in the context of climate change disruption too.
This is also a 'green' COVID-19 response, when planted with immune building plants, that is part of what should be a green COVID-19 etc response built around the world which will build resistance antibodies in the individual and herd 'immune system'.
Also, see the 'Permachar Wicking Module (PWM)' page for a modular approach to wicking beds.