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Dahlia - sprouted indoors - most going crazy- can I put out in unheated GH

selinasallyselinasally Posts: 166
Hi there- first time growing Dahlias- I have about 12 which I potted up end of March and most have gone crazy- I have pinched back some but growth is prolific- they are on a windowsill - shall I put them into unheated GH to slow down growth a bit, before planting out in June and harden them off ? ( I feel so grown up using these words like I know what they mean !) 


  • chickychicky Posts: 10,379
    You don’t say whereabouts you are @selinasally, but they should be fine in an unheated greenhouse if there is no frost forecast (we don’t have any forecast here in the South East for the next fortnight).  They will be fine out there.

    If you do see frost expected then you could cover them with horticultural fleece for the night to keep them safe.
  • Nanny BeachNanny Beach Posts: 8,427
    Started mine off in a frost free green house,going to start putting them out overnight today if that makes sense! SE UK out of room these are y pots I need for my veg
  • Mark-EMark-E Posts: 182
    We have put ours in the greenhouse to slow the growth a bit as they were getting leggy in the house. They seem to be fine in there.
  • selinasallyselinasally Posts: 166
    Thanks all - I am in London should be frost free
  • Have any of you started giving them a feed yet? Mine have been indoors the whole time, sparingly watered, and are now about 8-10 inches tall.
  • BiljeBilje Posts: 740
    I’m in NE England, mine were potted up in March a few a week, in a cold greenhouse, plastic green house and a cold frame. Some were then put outdoors about 10 days ago and I’ve started planting in the borders. All seem fine despite cold temperatures. 
    I wouldn’t move plants from a window sill to a border just acclimatise them over a week or so. 
  • Nanny BeachNanny Beach Posts: 8,427
    Watch out for slugs they loo new Dahlias growth
  • selinasallyselinasally Posts: 166
    Have any of you started giving them a feed yet? Mine have been indoors the whole time, sparingly watered, and are now about 8-10 inches tall.

    Yes, get them in the greenhouse and start hardening them off now. Im in the North East and ours have been growing in the ( unheated) greenhouse from being planted up. I have moved some, now, into the cold-frame and some have gone outside ( in their pots) ( with a plastic dome over them on a night). All are growing and steady and bushing out , so I shouldn't worry about them @selinasally . Those in our greenhouse will be hardened off over the next few weeks. 
    BTW check your pot bottoms, if you can see some roots coming out, it is time to pot them on into a bigger pot. It might be a good idea, anyway, to  plant them into something larger, if the pots are getting full. 
    When I planted dup the tubers I threw in a teaspoon of granular feed 
  • FireFire Posts: 17,116
    I just split four dahlias today and got 25 plants from them. It's going to be 'Dahlia year' for me. Lots to keep and lots to give away.

    - -
    They grow so fast once they get going. Their final potting will be in a few weeks.

  • DitsyDitsy Posts: 174
    @Fire do you mean you split the tubers or took cuttings? I would love to multiple my dahlias.
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