Has anyone attempted growing roses year round in a temperature controlled greenhouse? I am in Zone 5. I have had the roses growing for 3 years and they are starting to decline. Can someone recommend the best soil combination to use. My beds are raised and not using the natural dirt as I have them on a heated floor throughout the winter.
Any advice is much appreciated!!
I have propagated & grown cuttings in a greenhouse heated in winter to keep above 35deg. The cuttings have been uppotted to 1gal and bloomed after the first yr. They are are in a top soil planting mix and set on the open gravel ground with no bottom heat. These are mostly OGR’s.
Unless you are making your own homemade soil, I would buy the best organic potting soil (not Miracle Grow.). I add perlite to it for draining. When I fill the pot, 1/2 way - I add organic fertilizer, then the rose, then add the rest of the soil.
I have not kept roses exclusively in a greenhouse as described and am not in the same zone as you, however, I would imagine there could be several causes for the decline you mention:
If they were doing well in the greenhouse previously, that is a good indicator that the greenhouse is suitable for them. As it sounds like they are still in larger, raised beds, I would add the same types of items you’d add outdoors to the soils. These would be alfalfa and rose food/fertilizer along with any additive needed to make sure you have slightly acidic soils. Also - rule out disease as the cause, as well as under/over watering. Another reason that might be perceived as decline but is actually a very quick fix would be if the roses have not been pruned back for the last couple years. They would have little new growth and fewer blooms. Lots of resource here in the forum and online will help you with proper pruning!
Let us know how they are doing!
Thank you for your advice! much appreciated