I have several gorgeous varigated New Guinea SunPatiens that I would like to save over the winter. I tried to save new guineas before with not much success. They did well for a couple of months and then died off. I tried to keep watering to a minimum, only when they truly needed it. I tried putting some under grow lights and I put some in a window that did not get direct sun. Neither areas survived all winter. What am I doing wrong?
My own experience of these lovely plants are they are very tender for winters and the conditions required to see them through is well beyond most peoples ability as they need sunlight, (not direct sunlight) but well lit, warmth without it being a dry heat from indoor heaters and no drafts from cooling systems, the other things they dont like is fumes from Gas appliances like boilers, or cookers, so when you consider all those things, it's not surprising it's difficult to get them right through the winter till the next spring.
IF you can meet these conditions, then go for it and just because it never worked the last time, take that as a learning curve and have another go remembering what you feel was wrong last time, I would say you should have gave them just a bit more water as when you break a stem off these plants, they are full of moisture, but again, not over wetting the soil, did they have a bit of heat, maybe that was the problem, I'm only suggestion things here.
the books say to keep the plants growing ALL year and flowering too IF possible, keep just wet and it may be that you loose ALL the leaves while doing this, BUT come March, you give a little more water, NOT over done. and the plants should fill out with new leaves again, at that stage I would give a half strength liquid feed. inside plants need shading IF set in direct sun.
Re-pot every second April after new growth has started.
Cutting are easier, you just remove a side shoot about 3-4 inches long, remove several bottom leaves and stick them in a glass of water, after a few days, week 2 at the most, you will see fine roots growing, leave them till you think the roots are hardy enough to be potted on into good well drained soil with added grit or horticultural sand from garden store, mix this about 3 scoops compost to 1 sand, then pot up and treat as parent plant, the parent plants might be still doing fine so care for both in the same way.
Always know there will be a few losses no matter how much experience you have as that is nature for you. good luck and have fun experimenting.
I think if you take cuttings you might be able to overwinter them indoors, and make a mini-greenhouse for them. This would moderate the temperature and humidity, and might make the difference. Cuttings are smaller, of course, so would need a smaller mini-greenhouse than the adult plant.
You could also place several of each cutting in different locations, knowing that you will lose some, but hopefully not all.
A lot of the time I make my own mini greenhouses when required, used both for seeds and cuttings,
I collect some of those clear plastic square containers we get strawberries or other soft fruit in at the suppermarkts, these are placed over either small seed trays and they allow light in, keep the seeds / cuttings at a warmer temp, they are easy to lift IF spraying / Misting is needed and you can cover them plastic covers with a sheet of newspaper if shade is required.
You can cut the bottom from round Cola bottles about 4-6 inches from the bottom and use the cut off bit like a mini greenhouse over a small pot of seeds too, it works the same as the square cover and set the pots with clear tops onto a tray for ease of bottom watering.
Hope this gives you some ideas to help you out and save you buying a lot of expensive equipment that MAY never be used again but all serve the same purpose.
Good luck, Take your time and enjoy.