Plants smell like rotten eggs

I flushed my plants yesterday. The pots were completely dried out before flushing. I checked this morning and that’s when I noticed a rotten egg smell. The plants don’t like bad they still look healthy. Should I be concerned?

What soil are you using @Garden420

@Garden420 have you watered in any sulfur products?

That rotten egg smell is a bad sign usually unless you inoculate with specialized microbes. Very distinct and only happens if you water in too much of a sulfur amendment or your conditions have been anaerobic too long and you have bacteria forming hydrogen sulfide (hopefully beneficial one) or have root rot.

There are some beneficial hydrogen sulfide producing bacteria though that will wake up in the right conditions. Are you using any special microbes? Is your substrate inoculated?

Thiobacillus bacteria are often included in microbe mixes to help balance the nitrogen/sulfur cycles and are both aerobic and anaerobic. If it is a bacteria causing it let’s hope it’s this and not e-coli. Lol

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I’m using foxfarm ocean forest soil. No special microbes. I’ve fertilize only once with foxfarm dirty dozen. After that I’ve been noticing bug activity so I drench with azamax. Then I let pots completely dry out then I flush with distilled water cal mag mixture. I’ve been watering every 5 to 7 days when pots are dried out.

@Garden420 you are using microbes then. The Bush doctor microbe brew and kangaroots are earth worm castings and kelp based microbe teas full of sulfates.

How much of that have you used? Have you followed the feeding instructions?

@Garden420 fox farm won’t release their full ingredient list but with the way their stuff smells it’s likely they use a breed of acidithiobacillus during acid hydrolysis which will break everything down and stabilize it for storage which is also likely why their nutrients are almost all acidic.

It’s likely just a build up of acidithiobacillus. What is your substrate ph currently?

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I have 3 plants c99#1 c99#2 and gdp. They’re all using foxfarm ocean forest soil. I experimented with c99#1 and gdp by using general hydroponics nutrients. For those 2 plants I fertilized with 3ml calmag 1tps big bloom 1tps micro. nutrients ph was 6.5 and runoff ph was 5.8
For c99#1 I used 3ml calmag, 1tps big bloom, 1/2 tps root drench, 1/2 tps wholly mackerel, 1/4 kelp, ph was 6.5 and runoff was 5.8 I didn’t totally follow foxfarm nutrient schedule but I did half strength with that feeding. C99#1 looked very healthy with no deficiencies. But the other 2 that I fertilized with general hydroponics started showing some sort of deficiency with leaves looking wilted and light in color in some spots. I don’t know if mixing general hydroponics with foxfarm soil caused some effects or what but they seem to be recovering now.

What are you using as your plant pots?

Ac infinity 3 gallon fabric pots

@Garden420 what is the soil pH? You need to do a slurry test or use a soil meter for that. It’s not the same as runoff ph.

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I’m guessing it’s about 5.8

@Garden420 so you’re using a reagent kit and don’t have a meter?

By the look and sound of everything though it’s low soil pH. I’d personally cut back on the nutrients for now because FFOF has plenty for a month or two of veg and top dress to fix soil pH.

Do you have any lime?

A quick fix is to use some baking soda and water but to compensate for the small pot size and acidic nutrients liming would be beneficial. I’d personally use some dolomite lime and amend using the instructions for container size.

Smaller pots are tough when trying to grow organic or do a soil grow because they’re really easy to over amend/over feed and there’s less soil to use as a buffer to forgive us being heavy handed.

I have ph meter but I need to get some calibration solution. I also have dolomite lime. I had to add some to my last grow because ffof soil is acidic and it did cause issues in my last grow. This my first time experiencing rotten egg smell. I was planning on switching to flower at end of this month but I may wait a little longer so plants have time to recover. I just hope I dont have root rot.

@Garden420 if they continue to grow healthy it isn’t root rot. It’s just a build up of those sulfur bacteria I mentioned which can be a good thing and increase your yield. Just need to keep the soil pH in range because that hydrogen sulfide will lower soil pH. Getting pH up will slow the breeding of tye bacteria too and the smell will die down and you’ll only get a hint of it on watering days really.

My current ladies have some sulfur smell after watering days too because of my microbe inoculate but they’re doing great. They’re loving it.


I guess they ok they look sick

@Garden420 looks like you just need to let them dry out a bit. Should probably stop watering to runoff too and start only watering with 5-10% of the soil volume max when the pots get dry. For 3 gallon pots this is roughly 500ml to 1 liter at a time. This will definitely help your plants in a soil grow in FFOF.


I’m in a similar situation at the moment. I reacted to very low room humidity during a weather front by overwatering my girls. They’re ok, just a little boggy today, and though not exactly sulfur, do smell dank. They’re autos at five weeks. I’m thinking they need a dry run of a few days, until they are about praying, :grin:.


soil meter is not accurate, lol.

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In 2 gallon fabric pots, I use 2 tsp of Fox Farm Grow Big per gallon tap water. If the plants are young, I use 0.5 L water. When plants grow tall, I use a gallon of feed/water every 2 days with 10% run-off.
To lower/stabilize pH, I use 3 tbl of garden dolomite lime in a gal water. Adjust the lime water pH. Use a pH value that gives you an average pH of 6.8. Example: if your soil pH is 5.8, use a dolomite lime/water mixture with a pH = 7.8. As time goes on, the soil pH will naturally decrease over time. With 10% run-off volume, the soil pH will take longer to decrease or possibly you won’t ever have to adjust the pH.