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High temperature in pot soil

CollareddoveCollareddove Posts: 173
in Plants
I seem to remember a few years ago, during a heat wave, being told that the roots in pots are very susceptible to high temperatures, 75 - 80°F being quoted.  I did try to insulate my pots with bubble wrap and polystyrene. But temp within pots is a bit lower than ambient temp, so was I wasting my time?  Pots certainly didn't look very well in the excessive heat.

Posts

  • ObelixxObelixx Posts: 30,090
    In heatwaves it's best to move pots to shade if you can and keep them watered or your roots will over heat and dry out very quickly - effectively cook.
    Vendée - 20kms from Atlantic coast.
    "The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
    Plato
  • Chris-P-BaconChris-P-Bacon Posts: 943
    Collareddove said:
    I seem to remember a few years ago, during a heat wave, being told that the roots in pots are very susceptible to high temperatures, 75 - 80°F being quoted.  I did try to insulate my pots with bubble wrap and polystyrene. But temp within pots is a bit lower than ambient temp, so was I wasting my time?  Pots certainly didn't look very well in the excessive heat.
    I try to keep mine well watered. Its the one time I'll deliberately use tap water - the water in my water butts can get warm too.
    It's also why I don't use metal as plant containers.
  • NollieNollie Posts: 7,529
    I have pots around my east-facing front door (no soil there) and employ all sorts of tricks to try and stop them cooking and drying out too much but I still have to water them like mad most days and occasionally hose down the outside of the pots with cold water.

    Light or white coloured pots reflect heat more, but I foolishly also have some lovely dappled grey glazed ceramic ones that I’m loathe to part with. I place non-porous plastic pots inside the decorative ones and insulate in between, plus paint the insides of the outer pots white. I try and shade the vulnerable pots by putting in front of them other ones containing super drought-tolerant plants that don’t mind being baked so much. The big rose pots are too heavy to move so I have even resorted to using temporary parasols and other shading devices during heatwaves (like now, currently 38c). To cut a long story short, shading your actual pots, even if you don’t want to shade the plant in it, helps.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • CollareddoveCollareddove Posts: 173
    I see thst @Obelixx and @Nollie speak from very personal experience living in much hotter climes than UK.  I guess this is something I/we shall have to get used to in the coming years.
  • ObelixxObelixx Posts: 30,090
    I gardened for 25 years in Belgium before moving here.   It's much wetter and cooler but could get to 38C in heatwaves.  Even a normal mid 20s can be too hot if the pot is in sun all day and the compost inadequately watered.  
    Vendée - 20kms from Atlantic coast.
    "The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
    Plato
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