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Cactus turning brown

LeadFarmerLeadFarmer Posts: 1,500
in Plants
I have some cactus that were grown by my late grandfather and some must be about 40 yrs old. One in particular lives on my south facing kitchen window cill and has gradually started going brown.

Anyone know why this is happening? It is in gritty compost and gets watered maybe once per month, sometimes with tap water sometimes cooled down water that has been boiled in the kettle. I mist spray it once or twice per week, for no other reason than I assume plants like this.




Posts

  • DovefromaboveDovefromabove Posts: 88,147
    I don’t think cacti need misting …

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





  • Balgay.HillBalgay.Hill Posts: 1,089
    edited May 2022
    Did you water it over the winter? I made that mistake before, and lost a plant to rot. I found advice too late on a cactus forum that said to stop watering from Oct. to March, as the cactus is dormant.
    You have plenty of offsets you could plant as insurance.
    Sunny Dundee
  • GardenerSuzeGardenerSuze Posts: 5,692
    I agree with both these comments house plants are new to me but I wouln't mist cacti.
    I have worked as a Gardener for 24 years. My latest garden is a new build garden on heavy clay.
  • LeadFarmerLeadFarmer Posts: 1,500
    I will have watered it over winter, but now I know not to.
    Maybe I should remove some of those smaller cacti and pot them on, to be safe. I assume they just pull away easily? Do they just need regular compost but with lots of grit?
  • Balgay.HillBalgay.Hill Posts: 1,089
    edited May 2022
    I've been repotting using 50/50 John Innes no.2 and Perlite. It seems to be working out ok. I also use large grit as a top dressing.
    Tip the whole pot on its side and gently remove the cactus from the pot. Try to take as much root as possible with the offset. Don't water the offset for six weeks. This applies to any cactus you repot. Something else i learned from the cactus forum.
    Edit. It might have been 2 weeks, not 6. I'll try and find the info again.
    It was between 1 and 3 weeks! :)
    This link gives a good description of repotting if you scroll down.
    https://www.forum.bcss.org.uk/viewtopic.php?p=292623&hilit=repotting+cactus#p292623
    Sunny Dundee
  • LeadFarmerLeadFarmer Posts: 1,500
    Balgay.Hill said:
    I've been repotting using 50/50 John Innes no.2 and Perlite. It seems to be working out ok. I also use large grit as a top dressing.
    Tip the whole pot on its side and gently remove the cactus from the pot. Try to take as much root as possible with the offset. Don't water the offset for six weeks. This applies to any cactus you repot. Something else i learned from the cactus forum.
    Useful advice, thanks.

    Maybe I need to find the cactus forum seeing as some of mine are maybe 30 - 40 yrs old. My grandfather obviously knew how to look after them, so it will be a shame if I loose them.
  • Balgay.HillBalgay.Hill Posts: 1,089
    LeadFarmer said:
    Balgay.Hill said:
    I've been repotting using 50/50 John Innes no.2 and Perlite. It seems to be working out ok. I also use large grit as a top dressing.
    Tip the whole pot on its side and gently remove the cactus from the pot. Try to take as much root as possible with the offset. Don't water the offset for six weeks. This applies to any cactus you repot. Something else i learned from the cactus forum.
    Useful advice, thanks.

    Maybe I need to find the cactus forum seeing as some of mine are maybe 30 - 40 yrs old. My grandfather obviously knew how to look after them, so it will be a shame if I loose them.
    See my edit with added link to the forum. :)
    Sunny Dundee
  • LeadFarmerLeadFarmer Posts: 1,500
    Balgay.Hill said:
    LeadFarmer said:
    Balgay.Hill said:
    I've been repotting using 50/50 John Innes no.2 and Perlite. It seems to be working out ok. I also use large grit as a top dressing.
    Tip the whole pot on its side and gently remove the cactus from the pot. Try to take as much root as possible with the offset. Don't water the offset for six weeks. This applies to any cactus you repot. Something else i learned from the cactus forum.
    Useful advice, thanks.

    Maybe I need to find the cactus forum seeing as some of mine are maybe 30 - 40 yrs old. My grandfather obviously knew how to look after them, so it will be a shame if I loose them.
    See my edit with added link to the forum. :)
    Thank you.
  • LeadFarmerLeadFarmer Posts: 1,500
    edited June 2022
    This is another cactus I have which was also one of my late grandfathers and must be 40+ yrs old. It's lived in my mothers greenhouse for the last 10 yrs, and is about 55cm tall. One side has a brown patch which might be where it was against the shaded side of her greenhouse..




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