I’ve just purchased 4 new dahlia tubers and wanted to start them off early (Bergers Record, Friquloet, Bora-Bora and Labyrinth). The general guidance is that dahlias shouldn’t be grown outdoors until all risk of frost has passed and/or the nighttime temperature doesn’t drop below 10’C. In the North of the UK, that’s usually towards the end of May or beginning of June.
In previous years I have started tubers off in doors in pots. However last year I moved to a new house and don’t really have anywhere to put them indoors, especially as my tuber collection has grown too large to start them all off in the house. So I bought a very small Lean-to greenhouse/ coldframe W76 x D46 x H110cm.
So I have decided to experiment this year by planting the tubers in small pots with potting compost and perlite lightly watered and I have placed these in the greenhouse in early April….fingers crossed they will do ok outdoors as I have no idea what temperature the Greenhouse is during the day and night. I should probably insulate it with bubble wrap. let me know if you have any tips or advice.
I plan to leave the tubers in these small pots for as long as possible just to give the tubers enough time to sprout and produce shoots..then I will plant these out into a patch of garden I have already prepared for them.