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Stinky sulfur bacteria in soil

After testing my water in my tray, I realized I had an infestation of bacteria in the soil of some of my pots. The stench was a clear sulfur/rotten egg smell coming from the soil of some pots. Oddly enough all of the soil in these pots is less then a few months old (no more then 5-6 months). I know this is due to sulfur bacteria residing in the soil but my question is; do I need to repot EVERY pot which came in contact with the same water or just the 'bad' pots? And do I need to change out the water? I've already changed out the water twice and repotted all of the pots which I thought were infested but apparently I must have missed 1 or more as the ppm in the water keeps rising. It was at 12ppm this morning after a fresh change and tonight was at 98 ppm. I'm assuming it'll keep rising over night as well.

I flushed the bad pots and tested the water coming from them and results came in at ~398 ppm. Oddly enough none of the plants seem to be declining *yet* (knock on wood) but i'm afraid that I now have to repot every single plant in the tray in order to get rid of this infestation.
I also noticed that the bad pots were only coming from pots which were in a silica sand/peat moss mix while my perlite/peat moss did not have this issue.
Has anyone dealt with this successfully before? Thanks for all the help.
 
The rotten egg odor is usually hydrogen sulfide produced by anaerobic bacteria and -- other than replacing the compost -- flushing is your best bet to oxygenate the soil. Also, testing the TDS from water that has been flushed through a pot tells you virtually nothing; any particulate matter in the water at all will raise the ppm.
 
The stink is probably coming from anaerobic bacteria. In general, a change in conditions will fix the problem. I've had this happen in pots that stay too wet and/or compacted. If your mix has a tendency to compact and retain too much moisture, it may be best to replace it.

There's a good chance a good flush and letting the media dry out more between waterings (if possible) will do the trick. So long as the rest of your pots don't promote the growth of anaerobic bacteria, they should be fine.
 
i get it a lot, mostly in boggy, stagnated pots. Its nothing that'll harm your plants (in my experience). If you dont like it, just let the soil dry out, rehydrate it, and tuh-duh, its fixed. :)
 
Wash your material? :/
 
Ok, thanks for the help guys. I will have to add more sand to my mix from now on in order to aerate better. I thought 50/50 would be ok but I guess that must not be enough. I'll be letting my pots dry out a little bit from now on that way I wont have to wonder if it's the soil or the dog :-))
 
If the microbiologist might chime in :D

You will never "get rid" of the anaerobic bacteria, they are there no matter how much you wash/flush/whatever. Bacteria are ubiquitous. Just the way it is.

Changing the media will put off the issue for a bit but in time the bacteria will multiply up again and you will get the stench again.

Best way to keep their numbers low and avoid the stench is to put a layer of grit or gravel or large chunk charcoal in the bottom of the pot. And then let the water in the tray dry out for a day or so before watering again. This allows air to penetrate the lower portions of the pot, keeping their numbers down.
 
Thanks for the input Pyro. I figured there was no way to get totally rid of them, that was not my goal though as soil faunas are unavoidable and sometimes beneficial to the plant itself. What I was mainly shooting for was a way to keep them under control so that 1) I dont have the nasty sulfur smell and 2) it doesnt make my PPM rise like crazy so that if by accident some organic matter found it's way into that water, it wouldnt be masked by the sulfur readings.
Sounds like the best way to keep them under control is by letting the water drop and aerating the soil better.

I am curious though because I have never ran into this issue with my outdoor collection and literally no air can penetrate the bottom of the pot the way I am growing. Are indoor conditions just ideal for these stinky guys?
 
The question I have is how harmful are these bacteria and their by-products to the plants? I can't imagine the sulfur compounds in high enough concentration as being beneficial. And the sulfur has to come from some where, probably by the bacteria breaking down organic matter. Again I can't imagine the nutrients released and not used by the bacteria to be beneficial if in high enough amounts.
 
  • #10
The question I have is how harmful are these bacteria and their by-products to the plants? I can't imagine the sulfur compounds in high enough concentration as being beneficial.

Those were my assumptions as well, which is why I drained the water as soon as I saw those readings being so high.
 
  • #11
it doesnt make my PPM rise like crazy

I'll be honest with you, your PPM does not sound like it is that high even with the bacterial byproducts. Way way way back in my early days of CP growing someone explained it to me like this. Imagine 3 stacks of pennies; the first 10 high, the second 100 high and the third 1000 high. Now step back 100 feet and look at the stacks. You can not really see the 10 stack, the 100 stack is there but not much to see and the thousand stack sticks out like a sore thumb.

I am curious though because I have never ran into this issue with my outdoor collection and literally no air can penetrate the bottom of the pot the way I am growing. Are indoor conditions just ideal for these stinky guys?

Outside, there is greater exposure to a vast cornucopia of other microbes that just do not generally hang out inside. The competitive nature of all these beasties keeps them all in check relative to one another.

The question I have is how harmful are these bacteria and their by-products to the plants? I can't imagine the sulfur compounds in high enough concentration as being beneficial. And the sulfur has to come from some where, probably by the bacteria breaking down organic matter. Again I can't imagine the nutrients released and not used by the bacteria to be beneficial if in high enough amounts.

NaN, these sulfur compounds can become quite toxic depending on the plant. I had a hell of a time with my Orchidioides and Iperua Utrics when it came to these and I have noticed decline in Sarrs and Drosera in "advanced" cases
 
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