Messages posted to thread:

Cindy-Hope14-Nov-01 09:12 PM EST 5a   
Doug15-Nov-01 12:43 AM EST 3a   
Dave15-Nov-01 07:20 AM EST   
JoanneS15-Nov-01 03:57 PM EST 3a   
Cindy-Hope15-Nov-01 10:34 PM EST   
Will Creed, Horticulturist18-Nov-01 06:52 PM EST   

Subject: houseplants and mould
From: Cindy-Hope
Zone: 5a
Date: 14-Nov-01 09:12 PM EST

I live in an apartment and just lately, after repotting all of my plants I have developed mould on the majority of my pots. On the surface of the soil there is a grey/white coloured mould. I have 2 cats, so when I repotted I added moth balls to discourage my cats from digging. So far they aren't digging but the mould is not helping my asthma any.

Can anyone offer any suggestions? Help!


Subject: RE: houseplants and mould
From: Doug
Zone: 3a
Date: 15-Nov-01 12:43 AM EST


did you use a sterilized potting soil? If not that could be the initial source of the mould spores. If your plants are able to handle a double shock, I would take them out of the soil and remove the visible mould. Then put small amounts of slightly moist soil in you microwave or oven (in a dish) and run it at high for about 3-4 minutes. This should be sufficient to kill any spores left in the soil.

Another possible cause could be overwatering/water sitting in spots. To prevent this water only when the top inch of soil is dry and add perlite or vermiculite to your soil mix to increase drainage and air spaces in the soil.

Hope this helps you.


Subject: RE: houseplants and mould
From: Dave
Date: 15-Nov-01 07:20 AM EST

Last week, Ed Lawrence on CBC Radio dealt with this problem. The mold is feeding off the new organic material you've put in the pots. Mold needs moist conditions to survive so take a fork and rough up the top 1/4 inch of soil. The top layer of soil will dry out and with no moisture the mold will die. The additional benefit is that you'll need to water less often as the top layer of soil is dry and the moisture will not wick up to the surface and evaporate. I've done this a couple of times when bringing plants in for the winter and it really works and a lot less work than microwaving all your soil.

Subject: RE: houseplants and mould
From: JoanneS
Zone: 3a
Date: 15-Nov-01 03:57 PM EST

I had the same problem and it was recommended to me that I stop watering the plant from the top. That I should add the water to the dish the plant sat in, and the plant would soak up what it needed. It worked for me.

Subject: RE: houseplants and mould
From: Cindy-Hope
Date: 15-Nov-01 10:34 PM EST

Thanks guys I will try a few of these suggestions. You may be right about the watering from the bottom. I have one pot with no mould. Its a self watring pot that waters from the bottom.


Subject: RE: houseplants and mould
From: Will Creed, Horticulturist
Date: 18-Nov-01 06:52 PM EST

I suggest that you unpot your plants, discard the fresh (contaminated) soil that you added, and put the plants back into their original pots.

I know this sounds crazy, but I am willing to bet that the repotting was not necessary in the first place. Plants do much better when potbound. Not only is the added soil contaminated with fungus spores, it is probably not porous enough. That means that even if you solve the mold problem, you will probably eventually rot out the roots. I have seen this happen hundreds of times.

In order to post the forum, you must register to the site.
To register, click here.

If you have already registered, you must log in.
  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row