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Brown and dying dahlias

Ann85Ann85 Posts: 64
edited August 2022 in Plants
Hi we have our Dahlias in pots but they have all started to brown and a couple have outright died. 

Could it be:

a) just too hot in Kent? 
b) the seaweed feed I used two weeks ago? 
c) wrong watering? We water with a watering can in the evening. 

Thanks for any ideas. 

We usually grow Dahlias very successfully in our flowerbeds but had to move these out temporarily. They started fantastically in May and June but now look tragic 

Anna 
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Posts

  • FireFire Posts: 19,096
    edited August 2022
    You water with a fan?
    Are they planted in the ground?
    How were they before you gave the seaweed feed?
  • bcpathomebcpathome Posts: 1,313
    Just a guess at not enough water .
  • FairygirlFairygirl Posts: 55,117
    They do need a lot of food and water, but seaweed isn't really ideal for flowering plants. The slow release granular food or tomato food is more suitable. You can also have them i a bit of shade - they're perfectly happy with that, and in the sort of conditions you're having down there, that would be worth doing. 
    I'm not sure what you mean about the fan though. Do you mean a can?
    If they've got dried out, water tends to run through and not be absorbed, so it's worth doing the 'submerging in a container' method to get them fully hydrated again. If that's not possible, a tray under the pots, and water until they soak that all up. 
    Even here, I have to water all my pots of dahlias and sweet peas most days, because rain doesn't penetrate well enough, and they both need a lot of water to thrive.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • Ann85Ann85 Posts: 64
    Fire said:
    You water with a fan?
    Are they planted in the ground?
    How were they before you gave the seaweed feed?
    They are in big plastic pots. Sorry I meant *can (watering can). 

    Tomato feed (diluted etc.) every two weeks before the seaweed (diluted etc.)
  • Ann85Ann85 Posts: 64
    Fairygirl said:
    They do need a lot of food and water, but seaweed isn't really ideal for flowering plants. The slow release granular food or tomato food is more suitable. You can also have them i a bit of shade - they're perfectly happy with that, and in the sort of conditions you're having down there, that would be worth doing. 
    I'm not sure what you mean about the fan though. Do you mean a can?
    If they've got dried out, water tends to run through and not be absorbed, so it's worth doing the 'submerging in a container' method to get them fully hydrated again. If that's not possible, a tray under the pots, and water until they soak that all up. 
    Even here, I have to water all my pots of dahlias and sweet peas most days, because rain doesn't penetrate well enough, and they both need a lot of water to thrive.  :)
    Thanks this is really helpful. We have a giant bucket for dunking plants but I didn’t think of this for the Dahlias. I will try this. And maybe tomato feed again. 🙂
  • Ann85Ann85 Posts: 64
    Does anyone know of the leaves do all die at this stage, is it worth storing the tubers over winter to try next year? I suppose if they look healthy and plump? 
  • FireFire Posts: 19,096
    If they really are dying back, then yes, keep the tubers for next year if they look plump and worth it.

    It's probably not a good idea to feed ailing plants. They more need to rest up and regain health. Feeding pushes them harder to flower. If they are not covering the basics, giving them 'steroids' and telling them to leap might make them feel worse. Maybe just stick to water, don't feed for the rest of the summer. See how they do.

    Dahlias come from south and central America and I don't think they would suffer from too much sun.
  • FairygirlFairygirl Posts: 55,117
    If you have a photo, we can maybe help further  :)
    Most dahlias flower on and thrive until quite late in the year - September/October depending on conditions/location. If the foliage got fried in the heat that's why they'll be brown. 
    The tubers should be ok, but if the plants are just short of water, they may well recover once rehydrated anyway.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • PlantmindedPlantminded Posts: 3,580
    Another consideration is the compost you have used, some are better than others at retaining moisture and providing nutrients.  In this heat potted dahlias can need watering more than once a day, but it's important that your pots drain adequately.  
    Wirral. Sandy, free draining soil.


  • Ann85Ann85 Posts: 64

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