Thank you for the great reply Dale.
Biomass is the key. Keeping out snakes and other vermin is also a priority. We have an abundance of Kooigoed, Everlasting, Imphepho (Helichrysum petiolare)
http://www.plantzafrica.com/planthij/helichryspet.htm and other Helichrysum species which we can use as biomass. The other option is our almost unending supply of Black Wattle (Acacia Mearnsii), which we can stack in there. A great solution except for critters & possibly unwelcome fungi.
The Khoikhoi used the leaves and flowers as bedding; campers still do the same today. Burning a mixture of Helichrysum and Artemisia afra leaves, makes a pleasant insect repellent. It is very effective at keeping flies and mosquitoes away.
I was wondering about
not adding biomass and rather closing up all of the gaps with the mountains of landscaper's fabric we have. In my mind this creates small little ovens of warm air that is constantly pushed up against the beds during the day and should retain more heat in the concrete when the temperature starts descending. Does anyone know if this will work? As the beds are N-S orientated the paths can also be covered with the landscaper's fabric to warm up faster during the day.
The compost + plastic pipe idea would seem to be a great additive if we get a cold snap. Would mounting the pipe underneath the concrete be needed or can it just lie on the brick 1m below the beds?
In our situation the beds would have to be outside - lack of space. Designing it into a greenhouse is not a bad consideration.
I included the drawing for you to see if the flat plate solar collectors would work in our situation.
Dale, the farm is situated in a rather safe area & province. Our 40ha falls under marginal ground in this area, so if things do go south we might be the last to feel it. Our government always say land claims are around the corner but this time it might be true as legislation is in the pipe-line, as I understand it, any race except Caucasians will be allowed to claim any land they please without the original "willing seller, willing buyer" clause.
As of yet I haven't seen many of these claimed lands being productive. There are numerous reasons for this but the main one for me is Education. The new owners have close to zero knowledge of sustainable practices.
So if anyone is willing to take the gamble on South-Africa you will find many farms (there was a fully fledged tea & dairy farm up for auction a while ago) for relatively cheap.
The only thugs we have here are the Baboons. Our solution for them will be part 6ft electric fence part FFF (Furious Food Fence) which will be made up out of Num-Num shrub (Carissa macrocarpa). Fruiting Rubus vines which turn into shrubs if you allow them. Kei apple (Dovyalis caffra) & possibly Molasses grass. Feel free to add to the fence.
Thank you for all of the input.