I have been looking it up and found key hole beds in youtube that were built up and as joel hollings worth said had compost in the middle so the central path lead to to the compost centre and you could throw in your kitchen scraps more easily,
The basket for scraps was also the place to water
the bed so the nutrients in the compost part passed into the water that ran through the scraps and into the soil.
the video was of a keyhole bed in Africa and i thought that maybe these small circular raised beds hold moisture better than a ground level bed would because the water in a raised bed
would not wick into the surronding dry soil.
The beds in the picture where about thigh hieght and surronded by stones. I htought that in a dry country it could be a good idea to have plastic walls to the keyhole beds that would hold in the moisture even better than stone walls. Maybe the roots
would get roasted you would have to shade the plastic walls.
In bill mollisons videos of dryland solutions keyhole beds he gives another reason for raised beds that it lifts the plants above the salty soil. Arid hot weather makes it easier to have salty soils it seems .
The soil of the beds as that in the bottom of the kitchen scraps basket was made of a mixture of ash
manure soil and hay i think
. It was a highly nutrative mix these beds are made for high production.
You stick four sticks into the ground where you want to have the centre of your keyhole bed and then add cross bits to your four sticks so they make a basket like square tube in the centre of the bed.
These beds grow a heavy production of vegetables in Africa where food is scarce. Normally a heavy production of vegetables in a small space is connected to a big supply of nutrients.
In the old back gardens in villages they had a lot of manure, privies were the normal type of toilet and pots under your bed, for those who did not want to go out into the yard in the night. My mother used to give visitors pots so they did not have to go down stairs to the bathroom, she enjoyed maintaining this old fashioned habit or she thought it was good for the ellderly a bit of both. We children had to empty the potties. I supppose the contents of the privies used to go onto a dung heap in the back garden . That would be a lot of manure for a small garden at least till the children leave home. No one talks of it as being a danger as town drains are that can get into the ground water system. Mind you I am not a historian.
It seems right to mention how much manure their used to be for the production of all the vegetables the family ate and in England in villages the majority of the vegetables were, probably still are by the traditional grown in the garden.
In england there is a village fair everyyear and one of the main events are the prizes for the best vegetables, other events are prizes for the best hand writing of children and flower arrangements . in big towns fo rhte best cow bull and such . The competition for the biggest carrot and such was fierce. rose macaskie.