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Watering begonia and Dahlias in pots

I have recently put new and old dahlia tubers and new begonia corms in pots - it is recommended that the begonia corms are not watered until growth is showing for fear of the corms rotting however the pots are now bone dry so should I water them and should I water the dahlia pots which are also bone dry now also with no growth. They are all in my small unheated conservatory/greenhouse although the temperature does reach up to 20 degrees when the sun is shining.


  • BiljeBilje Posts: 475
    Hello Guernsey..can't help with begonias but I do grow dahlias. I've been potting my overwintered tubers over the last two weeks..too many but that's another story! I live in the NE and my dahlias are in a cold greenhouse, a plastic mini greenhouse and a cold frame...bedroom window sills next. They are potted up in multipurpose compost and I do keep them watered but not soaking. That's the way I've always grown them and haven't encountered any rotting problems. Good luck.
    PS just remembered something about begonias..they have a concave top to I would imagine you have to be careful that an excess of water doesn't collect there.  
  • JoeXJoeX Posts: 1,357
    How often do you water the dahlias?

    ive just replanted my dahlias in pots and put them in a new mini plastic greenhouse along with some seeded pots.  I’ve noticed condensation pretty much straight away, if it matters.
  • Thanks Bilje, that has been very helpful, so I must keep them moist but not soaking, I think it is a question of keeping an eye on them Tin pot, and not letting them dry out.  I will be watering mine tomorrow. If the sun shines the peat dries out, but on a dull day they won't need so much if any watering at all Tin pot.
  • FireFire LondonPosts: 7,152
    My begs have been in beds all winter and I went and checked them this week and they are fine and hard tubers; in spite of snow and rain.
  • Nanny BeachNanny Beach Posts: 3,743
    Havent bothered with begonia (tubers) this year, dahlias, I buy Garden News, the expert chappie said to exlcude light because they shoot from under the soil, so thats what I have done, covered the pots with plant saucers, damp all purpose compost, havent watered them again, 7he says 7-10 days, they are in an unheated greenhouse, after 7 days they had sprouted, so I removed the saucers.  They have been outside in the days, but it was 6d last night (talk of snow tomorrow on the South Downs) so they went back in.  I did manage to overwinter some dahlias outside a few years back, I waited till the frost blackened the tops, then mulched them with straw and covered with an unturned metal hangin basket to stop the straw blowing off.
  • Thanks for your input Nanny Beach.  I have now got approx half of my dahlias growing successfully and some are now outside (in pots) day and night.  Three or four haven't done much which is very disappointing and the begonia tubers have been a wash out - I had twelve and only one or two have done anything - lack of sunshine, cold temperatures and perhaps my over watering too. Your system seems to have paid off, perhaps I will have more success next year!
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