Forum home Problem solving
This Forum will close on Wednesday 27 March, 2024. Please refer to the announcement on the Discussions page for further detail.

Dahlias looking ill

This year I'm attempting to grow dahlias but it looks like I've fallen foul of my inexperience. Planted two types of dahlia and both are not doing good. I've taken them
out of potting compost with JI2 and put them in Westland multi purpose compost with JI. I've also had an automatic watering system running that I've now switched off. The removed compost was absolutely saturated. Have I done the right thing. 
«1

Posts

  • FireFire Posts: 19,096
    edited May 2022
    Looks like four dahlia plants in one small pot might be ambitious. I would water when the soil seems to have dried out. I find dahlias to be very chatty plants that will tell you when the want watering - they go limp. Are the plants in full, all day sun? Did you buy them in flower?
  • They were bought in full flower and initially kept in a cold frame. They were doing ok until two days ago. They are in a full all day sun from about 10:00 to 18:00. 
  • GardenerSuzeGardenerSuze Posts: 5,692
    @davidgibbs.pl6srLpEO  WelcomeAutomatic watering systems are ok up to a point. I still think they need a lot of human intervention. I have known them to completely blow out of hanging baskets or as you say you can finish up with plants that are overwatered.
    I like to check pots by using a finger to see if compost is wet or not.
    I have worked as a Gardener for 24 years. My latest garden is a new build garden on heavy clay.
  • FireFire Posts: 19,096
    What are the bottom of the pots like? Big drainage holes? can the water flow away easily? you don't want them to be sitting in water when the plants are so new - you risk rotting the tubers. Check the pot of the pots for slugs and snails.
  • FairygirlFairygirl Posts: 55,117
    I agree with @GardenerSuze. These automatic systems seems to be quite hit and miss. It's better to check manually.  :)
    I think you may have to take a couple of those tangerine ones out though. There's not really enough room for 4 plants - especially greedy ones like dahlias. 
    They'll have been forced undercover a bit too, if they were already in flower when you bought them. They'll be a little weaker than plants bought at tuber stage to grow on, and may have needed a bit more warmth for  a bit longer before going out. 
    They may have suffered a little bit due to that, and especially if the soil was very soggy. They do need moisture and food, but they also need really good drainage. As they're in good amounts of sun, they should do a bit better now. Did you mix some grit in with the soil mix? That would ensure they won't get too waterlogged if they do get a bit too much water.  :)

    The slugs are one of the biggest problems at this stage too - as you're discovering  :/

    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • punkdocpunkdoc Posts: 15,039
    Agree with other comments.

    Too many plants in too small a space. Dahlias need lots of food and water and space to grow.
    How can you lie there and think of England
    When you don't even know who's in the team

    S.Yorkshire/Derbyshire border
  • It's lessons learned for me. I've just spend the afternoon switching them
    all in to a different compost. Unfortunately I didn't mix any grit. What sort of proportion should I mix. And yes, something is eating them but can't catch them. I've even been out is the dark with a torch. 

    Fairygirl said:
    I agree with @GardenerSuze. These automatic systems seems to be quite hit and miss. It's better to check manually.  :)
    I think you may have to take a couple of those tangerine ones out though. There's not really enough room for 4 plants - especially greedy ones like dahlias. 
    They'll have been forced undercover a bit too, if they were already in flower when you bought them. They'll be a little weaker than plants bought at tuber stage to grow on, and may have needed a bit more warmth for  a bit longer before going out. 
    They may have suffered a little bit due to that, and especially if the soil was very soggy. They do need moisture and food, but they also need really good drainage. As they're in good amounts of sun, they should do a bit better now. Did you mix some grit in with the soil mix? That would ensure they won't get too waterlogged if they do get a bit too much water.  :)

    The slugs are one of the biggest problems at this stage too - as you're discovering  :/

    Fairygirl said:
    I agree with @GardenerSuze. These automatic systems seems to be quite hit and miss. It's better to check manually.  :)
    I think you may have to take a couple of those tangerine ones out though. There's not really enough room for 4 plants - especially greedy ones like dahlias. 
    They'll have been forced undercover a bit too, if they were already in flower when you bought them. They'll be a little weaker than plants bought at tuber stage to grow on, and may have needed a bit more warmth for  a bit longer before going out. 
    They may have suffered a little bit due to that, and especially if the soil was very soggy. They do need moisture and food, but they also need really good drainage. As they're in good amounts of sun, they should do a bit better now. Did you mix some grit in with the soil mix? That would ensure they won't get too waterlogged if they do get a bit too much water.  :)

    The slugs are one of the biggest problems at this stage too - as you're discovering  :/


  • I've got some others still under cover. Not in a hurry to get them out given what's happened here. Looks like I'll be buying some grit tomorrow. 
  • FairygirlFairygirl Posts: 55,117
    The grit will just help if they're in danger of being over watered. If the compost is decent, and doesn't hang onto moisture too readily, you wouldn't need much - a couple of handfuls mixed in. 
    It's one of those things though - it depends on the compost, and how much water they get. In a wetter area, it's useful. Less so in a drier one where you're having to water manually anyway, and can judge it more easily. Plants in pots will always need more attention than ones in the ground   :)
    Making sure the drainage holes at the bottom stay clear, is also important. 
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • GardenerSuzeGardenerSuze Posts: 5,692
    @davidgibbs.pl6srLpEO At this time of the year I am watching and checking my garden daily. I am retired so I am able to do this, when I worked I was checking other gardens and sometimes my own garden suffered as a result. It is true you do learn from mistakes and I still keep making them!
    I have worked as a Gardener for 24 years. My latest garden is a new build garden on heavy clay.
Sign In or Register to comment.