Last winter, I had 10 Sempervivums in terra cotta pots in the unheated greenhouse. Half of them did not survive. This year I decided to give the Semps a better chance by taking them out of the pots and putting them in one of the greenhouse beds. With other time commitments, it took nearly a week to complete the transformation, but today I finished it. I will keep the temperature above freezing for at least the next month so I hope that is enough time for the plants to get somewhat established.
As a quick summary, I removed half of the garden soil from the southwest bed (about 10 cubic feet) and replaced it with eight cubic feet of pumice and two cubic feet of coco coir. I topped it off with 1.5 cubic feet of pea gravel. Then I planted 13 Sempervivums, three Sedums, two Aloe Vera, and two Plectranthus 'Velveteen Aromatic.' The Aloe and Velveteen are not hardy, so they are in plastic pots that can be removed easily. I put them in there to give some height because Sempervivums generally aren't very tall unless they are flowering. A couple of the Sedums also have some height.
This is what it looks like after I placed the 20 plants. I'll take some macro images to show this better. Against my better judgment perhaps, I hit the bed with the hose to wash the dirt off the plants and gravel. I really need to get this bed to dry out before I turn the temperature down. Research indicates that Sempervivums have the best chance to survive the cold if they are dry, dry, dry.
It was nice outside so I moved ALL of the pots out to give them some air. I wish I could leave everything outside for a few days, but that is not possible for several reasons, namely deer and cold weather.
So I did move everything back inside, after doing some cleaning. The flowers will be overwintered in some manner, but most of the plants in the second image are not guaranteed a spot in the warm garage. Those Coleus (right corner) had better live up to their reputation as low-light plants because that is their only chance for survival.
Here are a few images of the succulent bed work in process. First I removed half of the soil, and stashed it in large containers at the house. Then I loaded nine buckets with soil from the bed, which left about four inches of soil in the 15-inch deep bed. The next step was to add layers of pumice, coir and soil. Here is the first batch of additives.
I kept adding layers of pumice, coir and soil, mixing as I went. This is the bed topped with an unmixed layer of pumice. This was a couple inches short of where I wanted to be so I had to stop at this point for a couple days before I had the chance to get some more pumice and coir in Billings.
Once I mixed in the remaining materials and topped the bed off with the pea gravel, I started planting. I started slow with Sempervivum 'Powdered Pastry' at center, and the two Aloe Vera in buried pots.
It took me three days to finish planting because I only had about an hour a day for greenhouse chores Thursday-Saturday. Today I made the final push. There is plenty of space between the plants now, but if they take off and start crowding each other it will be easy enough to put some of them back in pots.