Hello Arturo - I'm glad that the seeds are doing well with you. I agree with Rick's advice. How warm is your heated greenhouse? I have one that I keep above 5.5C/42F. You can keep the formosanum at these temperatures and they will continue growing slowly. I think they will be fine with this. My L. formosanum var. pricei seem to be doing fine in my greenhouse from a September 2021 sowing. They are still in the flats they were sown in and I will pot them on shortly as Spring arrives (but we had 2" snow overnight and temps are going down to 23F/-5C tomorrow night, so we are not there yet). The L. pardalinum x kelloggii should do fine in the cool greenhouse. They won't mind a bit of frost. I think you just need to be a little careful on the watering they get, depending on how free-draining the compost is. Don't overwater them when they are dormant, but I expect you are aware of this from all the other plants you have grown.
As for your bulbs in growbags, then Rick and others who live in areas that are quite a bit colder than -º5C/-º6 in late winter might be better-placed to reply. How many growbags do you have, and how easy is it for you to dig a trench for them? While the bulbs in growbags might be Ok at these winter temperatures, I know it has taken quite a bit of effort on your part to get the bulbs to Argentina, so you may want to err on the side a caution during their first winter. Can you put the growbags in your cold greenhouse for the coldest month? I don't know what options you have for protecting the growbags if they are left on the surface. Any kind of mulch or tarpaulin covering might help if they were left out in the open. Is cold often associated with snow with you? If it snows then turns cold, which is often the case here, then the snow covering does help insulate the ground from the cold temperatures. But here the cold only lasts 5 days or so before a new low-pressure front from the Pacific brings rain and above-freezing temperatures. So my cold periods are short-lived, unlike those of Minnesota.
Hope this helps for now. Will write again later. Best regards, Steve
