Asked on May 31, 2020

I made a terrarium to house some succulents and cactus plants

DuncanespieDeb KCynthia H


The construction of the clear plastic material was ok, and the perlite and loam potting mix was as instructed, but when I planted it out, and gave it a sprinkle of water, a fungal growth appeared within two days, so I removed the plants and abandoned the idea of the Perspex lid.

I’m looking and some say to microwave the mix before using.

Does anyone have any experience like this?

8 answers
  • Well I have never put a lid on a terrarium. It may have to do with your climate as well. I am in 9b with extremely low humidity. But it gets very hot, the other day it was over 100°. If I would not have moved a few, they would have died. Anything in glass in direct sun will literally fry the plants.

    I don't understand the need for a lid unless in a cooler climate, but even then, without fresh air, anything will mold.

    Here is how to sterilize potting soil.

  • Duncanespie
    on May 31, 2020

    Hi Ms Moore,

    I live in the middle of the UK, the temperature varies quite radically, mid-day today was 76 degrees, By 19:30 it had cooled to 60 degrees, and tonight it has chilled by a further 15 degrees. The idea of the terrarium is that a fairly constant humid climate can be maintained.

    live read through your attachments, and it seems that micro- wave is the solution, I’ll need to see if a standard compost can be used. My sister lives near Melbourne Australia, and her cactus and succulents grow quite happily outside.

    I’ll try some ordinary potting compost first, and seal it in the terrarium, to see if fungus growth occurs.

    Many thanks for time.

    Kind regards


    • Awe, Duncan, you are so sweet! Yes the middle of the UK is a completely different climate. Sounds like you are right, microwave the soil. You have an excellent plan, go with it. You have nothing to lose by trying. Wishing you much success. 🌞

  • Agnes Chrzanowska
    on Jun 1, 2020

    I am following that question ..would love to learn about that too

  • Sharon
    on Jun 1, 2020

    Are you putting in gravel at the bottom a layer of netting, and then your soil? also only use potting soil as its been heated to destroy mold spores.

  • Craft Invaders
    on Jun 1, 2020

    In my experience nether cactus or succulents do well in enclosed terrariums (despite what you see in magazines). Neither of them like humid conditions which is what you are creating. Ferns and mosses is what I would suggest for enclosed terrariums.

  • Cynthia H
    on Jun 1, 2020

    I'm plant and cat sitting for my daughter right now, and hers has a hinged roof that you open to water and "garden". It isn't tight fitting so there is air circulation. She has basil and catnip growing in hers in small pots to contain them. She's had success with others too. Make sure fresh air can get in and don't over water. Good luck and stay safe!

  • Deb K
    on Jun 2, 2020

    Hi Duncanespie, here is a little video for a succulent terrarium, hope this helps you,

  • Duncanespie
    on Jun 3, 2020

    What I’ve decided to do is, I’ve ordered 3 dishes

    I’ll plant the succulents in these, with potting compost with fine grit.

    I’ll replant the terrarium with air plants/ cactus, I had terrible trouble finding activated charcoal for plants, most is for ponds, but found some.

    It should do well with air plants/ cactus, just need to microwave the soil to 200 degrees Fahrenheit to kill spores in the soil.

    We have a problem in the U.K. in that we’re still on partial lockdown, and deliveries are chaotic at best. strange though that with all the expected job losses, you can still go and buy a car, maybe it’s to live in!.

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