Last year I started reading about so called highland papayas and got really fascinated by them. I ordered some of my seeds online and I got some seeds from one member of this forum (rarefruit). Since I live in the temperate region (USDA zone 6) i knew i will have to find a way to overwinter them indoors. This has proven to be quite a challenge since most of species demand high humidity and a lot of light, together with temperatures above 0°C. As a precaution a have donated one plant of every species that I have to botanical garden in Ljubljana, so in case i fail in keeping rest of them alive, some of the plants will live on and maybe serve as source of seeds in the future. The purpose of this thread is to write about my experiences with growing highland papayas in temperate regions and most importantly how to overwinter them (and how to avoid making same mistakes as me).
Vasconcellea cundinamarcensis (syn: Carica pubescense): this is one of the rare species of Vasconcellea that you can actually find some information on cultivation. That being said, I had by far hardest time keeping it alive. It doesn't like having cold and moist soil at the same time because it's roots start to rot (it is same with all papayas). Twice I have lost all plants because of root rot and once snails eaten all leaves (plants survived, but died in the winter because of the root rot). Now i am planning to sow them for the third time. So the lesson here is: keep them somewhere where snails can't get to them and keep them somewhere worm in the winter. Also, water them very sporadically (colder the temperature, drier the soil).
Vasconcellea goudotiana: compared with V. cundinamarcensis I had very little trouble with growing this species. I have kept them in a place where temperature never dropped under 5°C, with fair amount of sun (although we have a lot of cloudy or foggy days in winter) and I didn't water them much (to avoid root rot). Because there was not enough sun they started dropping leaves, but still kept some of them and have by now stopped dropping them since days are getting longer. But they did make flower buds trough the winter-probably because of stress caused by lack of watering. All my plants have survived and are tallest of all papayas planted last year (30+cm ). If anyone would like to grow a species of highland papaya this is the one I would recommend.
Vasconcellea monoica: this species has been moderately difficult to grow. I had some troubles with those I kept in the same place as V. goudotiana, probably because minimal temperature was too low. Once I moved them somewhere warmer they got better, but i still had problems with leaf edges getting brown and eventually dropping off. This was maybe caused by some disease, but strange thing is that V. monoica was only species with this problem. Now that they are in a warmer room and days are getting longer i don't have any problems with them.
To be continued...