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New Seed Box Hot Bed

Hi All
I have just built a seed propagator seed bed using a soil heating cable.
I have set it at 18 Deg C.
I have put a plastic cover over it. But it is getting very wet and humid inside.
Should I have the plastic cover over it or not.
What do others do or think ????? 


  • FairygirlFairygirl west central ScotlandPosts: 46,981
    That's what the plastic lid will do when it's over soil that also has heat. Same principle as a plastic bag over a pot on a warm windowsill  :)
    If you've already sown seed, you'll need to open a vent on the lid [or move it slightly to allow a gap] to help mitigate the amount of moisture. You'd remove it completely when seed germinates.  :)
    It's a place where beautiful isn't enough of a word....

  • Pete.8Pete.8 Billericay, EssexPosts: 8,843
    I put about 1" of sand in the base of my propagators. It holds heat so keeps the temperature stable and keeps the moisture level high but I always keep a couple of the vents open.
    Once seed germinates I open more vents.
    I also keep mine set to 24C until seed has germinated, then lower it to 22c then 20c  - but the temp. depends on what you're growing.
    With decent heat, moisture and light the plants grow quite fast.
    If you get the balance wrong and it's too humid there's a risk of damping-off disease when seedlings just keel over for no apparent reason. It is caused by fungi
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • Thanks.
    That info is very helpful
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