Hot beds for fall rooting
I use to use hot beds quite a bit to overwinter tropicals & found they worked well to provide bottom heat for rooting roses. I had a very good success rate using this method starting in the fall.
I created the beds by digging out a trough in the garden 6" or more deep (some were 8-9" or more). I'd pile the dirt on one side & use that hill for planting veggies.
Through the year I'd fill the trough with organic material. Late summer I'd be sure to stack in plenty of rotting hay & keep it all watered.
In early fall, the best time for me to do rose cuttings, I'd set the cuttings in their pots into the hot fermenting bed. When late fall temps got cool enough I made 3-4' hoops from light weight pvc pipe stuck down into the bed. When temps got cool enough I pulled clear plastic over the hoops & anchored it. During most days I could leave it open. The combination of a hot fermenting bed around the pots, the humidity of wet hay & the cool fall temps that let me set the cuttings in full sun worked very well.
To grow great winter vegetables I would rake the soil I'd excavated from the trough back over the composting material then plant seeds--really grew great lettuce, broccoli, etc.