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Germinating Dahlia and Crocosmia

Hi All, I have planted in pots a fair number of Dahalia and Crocosmia tubers and corms and despite them being planted since the beginning of March I am seeing no growth at all. I planted them in a medium grade Sphagnum moss mixed with some perlite and placed them in a bright, but not overly warm (in the Scottish Higlands) spot in a polytunnel unfortunately without doors. Is it the temperature or the medium that is not right or is it both? I would welcome some comments. Thanks 


  • DovefromaboveDovefromabove Posts: 86,126

    Patience Rich - it's early days yet image

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • LynLyn Posts: 22,873

    Put the crocosmia bulbs straight in the garden.

    You can start the dahlia tubers off in any old compost, I save some from old pots. When they shoot and are about 4/5 inches tall, you can put them in big tubs if thats what you want, or plant out in the garden, buy mine wont get planted out until the end of May. Beware of slugs, they will nip the tops off as soon as they shoot up.They do need warmth to get them going, have you got a conservatory or a window sill.

    Gardening on the wild, windy west side of Dartmoor. 

  • Rich VDPRich VDP Posts: 12

    Thanks so you reckon I need to wait for a temperature rise?  Bearing in mind it started snowing again today !

  • Rich VDPRich VDP Posts: 12

    Thanks Lyn I've got some on a bright but unheated windowsill and some in an old polytunnel with no doors. I have covered them with fleece on really cold and windy days. I have also planted some of the crocosmia directly into the ground and still not a sausage. I was wondering if my sowing medium Ie the sphagnum moss was lacking in nutrients too much?

  • LynLyn Posts: 22,873

    Thats ok for lining hanging baskets, I wouldnt grow anything in it.

    Give the crocosmia time, if they were newly bought they may not come up until the summer.

    The dahlias definitely need warmth, the polytunnel is far to cold taking where you live.

    Gardening on the wild, windy west side of Dartmoor. 

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