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Powdery mildew in medium

IT seems I have powdery mildew in my media as I put in new chard plants in different grow bed from where they grew before and these showed up with powdery mildew. My beds are connected to the same fish tank. I have Actinovate which I have used in my outdoor soil based garden with great success. I'm wondering if it will kill the fish. Anyone have experience with this?

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Permalink Reply by Jim Fisk on February 6, 2014 at 8:35am

Hi Linda, Wish you had some pics at your home page so we can get a better idea of your system. IF you are in a GH as I recall you are, have you tried keeping a fan going to move the air? That cured many problems I was having in our GH.

Permalink Reply by Linda Logan on February 6, 2014 at 9:01am

I do have a fan. It is just on my chard and isn't on every leaf but is showing up on new growth. Are you familiar with Actinovate? Says it is safe for pets and is a natural microorganism. I may just do a foliar spray.

I'll put up some pictures soon.

Permalink Reply by TCLynx on February 8, 2014 at 9:41am

Linda,

I have use a tiny bit of Actinovate before but I have not extensively tested it with fish. My fish are channel catfish and I think I may have used a spoon full of the stuff in each bed on one of the systems with no apparent problems but I can't say if it was enough to have solved any problems either.

My experience with powdery mildew is that it tends to attack plants suffering from potassium deficiency or in hot dry yet humid conditions or both. So while a foliar spray of Actinovate may work, you may also find that spraying with seaweed extract or potassium bicarbonate will also work. If the problem is actually downey mildew and not actually powdery mildew the potassium bicarbonate will probably be most effective since it will also change the pH of the leaves which can combat the downey mildew as well.

Permalink Reply by Linda Logan on February 8, 2014 at 10:55am

Thank you. I'm pretty sure it is powdery mildew. I do add Potassium bicarbonate to my sump water which is what I pump into my beds which eventually drain back to the FT. When you made this as a foliar spray, what dilution ratio did you use. I generally do a heaping TBS to about 5 gallons of water when I pour it in my sumps. I doing this to add potassium but also raise pH. I also have seaweed extract that I can try.

Permalink Reply by TCLynx on February 8, 2014 at 11:47am

I've seen recipes for using anywhere from 1-3 TBS or 4 tsp of potassium bicarbonate per gallon of water for spraying. I would test with a small amount at the lower dosage before spraying everything.