green and black mildew or mold

[kdennis14]

Hello everyone,
I am in central Fl. I grow my orchids in my screenroom. We have had rain everyday for the past 2or 3 months. I have most of my orchids in clay pots. Many of them have mold growing
on the outside of the pot. Is this harmful? What can I do?

Thank you,
Karen

[Catt Mandu]

Hi Karen
You can try spraying and wiping the outside of the pot with a mild disinfectant such as hydrogen peroxide. If you are still watering despite the humidity, reducing the frequency of watering could help.

Good luck!
Posted via Mobile Device

[kdennis14]

Thank you Catt. I will cut back on my watering. I noticed that there is also some of the mold inside of the pots. Will this hurt the orchids???
Orchids are all healthy.
Thank you Catt, for your response to me.

[ksriramkumar]

Mold can provide environment for other harmful fungi to grow and its pores could also be allergic to humans and pets. You can wipe away with a mild disinfectant or use Physan 20 and drench the pot.You can also see if you can increase the airflow in the screen room by adding a fan.

[78Terp]

I have a growing number of orchids in clay pots here in the dry of Colorado. I haven't had the issue but I do run a fan in most places I have clay with the exception of a couple I have in orchidariums. So I agree with Sriram, use the disinfectant, water less often and increase airflow and the problem should be solved. I do like the fact the pots hold water in their pores but I can see the downside if stays too wet. How are your roots?

[raybark]

If it's green, isn't it more likely algae?

Over the last several years, my approach to growing has taken a fairly significant "shift", and I find i have far fewer issues with algae, molds, and rots:

1. I have drastically reduced the amount of fertilizer I apply. At one time, my fertilizer concentration was 100-125 ppm N, and now it's roughly 20% of that.
2. changed to a fertilizer formula that is very low in P & K (K-Lite, 12-1-1)
3. Stopped using disinfectants as a preventive measure, and try to avoid them altogether, unless I have a severe outbreak.

The reduction in overall fertilizer use, coupled with the low P, has essentially eliminated algae growth, even in S/H pots.

By eliminating the use of disinfectants, which kill beneficial microorganisms as well as pathogens, and by reinforcing those beneficials through the use of a plant probiotic (which also helps the algae reduction) I see overall healthier growth, with far fewer problems.

[sciencegal]

Ray, with the low P do you still get good blooming? I read that it isn't the amount of P but the kind you use that matters.

[kdennis14]

Hi,
I want to thank all of you for helping me to understand. The roots in all of my orchids are good. Harvey, should I unpot a bad one and look? I can add a fan, but I have to constantly watch as when it rains........But, I will do that. I will clean the pots as well. Now I have 2 that have the green growing inside the pot. What should I do?? I am sorry for all of the questions, but this is a new subject for me.
I want to thank y'all.
Karen

[78Terp]

My fan stays outside in the rain and when I water. It hasn't had any problems. Nor have I had to worry about getting shocked. And water has hit it and its electronics daily this summer.

If the mold is on media, I would replace the media while cleaning up the rest of the mold/mildew. As Ray suggested, lower fertilizer concentrations can help alleviate the issue going forward.

[kdennis14]

Thank you Harvey so very much. I just thought electricity ..water well you know. I will cut back on fertilizing for sure. It did not rain today for the first time in I do not know how long. I really appreciate your input. Thank you again.
Karen