I've got a few plants in a flood and drain system and a few weeks ago one of them just died. It seemed like lack of watering but i was unable to diagnose the problem until i pulled the plant and realised that the stem had rotted through below the pebbles and the plant was unable to take up water. I think that this is because the base of the plant had been sinking and it had ended up 3/4 of the way down the pot it was in so must have been exposed to lots of moisture. The system is draining enough so that it wasn't perpetually in water.

The problem now is that another one has just done it. I could deal with losing one but i can't deal with two and i definitely don't want to lose anymore. The one that has just died today (or is on it's last legs at any rate) has not been pulled yet because i'm waiting for the photoperiod to start so i can get down there with suitable (non-green) light and have a real look. Any Ideas on how to rescue this little gem?

I'm going to have a thorough look at all my plants and see which ones have migrated to the bottom of their bucket. Anyone got any ideas what i can do with these? I'm thinking that they somehow need to be raised back up the bucket but I don't know how i can do this really. I suppose i'm just going to have to empty all the pebbles out of the bucket, hold the plant up and then refill below it! Plants are now in week three of flower and look like they are gonna be the best ones ever so I don't want to lose them... it might make me cry! My res is at around 25-26C for part of the day; could this be the problem? If so i might have to invest in a chiller which will not make me happy either but if i have to do then i'll do it.

Thanks once again for any help on this one guys. Thought that this would be the first faultless grow but oh how wrong i was:(

Oh... I've just realised that this is my first post on this site! My apologies, i've been reading on here for some time and had just presumed that I had posted. So... hello everyone:)

welcome m8,

im no expert but i think once they get stem rot its over

your res does seem a tad warm, freeze two litre coke bottles full of water an put in res

i hope the others are okay

Pull the pot too, when you do that check and see if the roots may have clogged the line... and check the other plants and make sure it's not pythium spreading through out the rest of the lines... good luck with'em and I hope it don't spread...

Cant help you with the stem rot I'm afraid, but here's a tip to stop it happening again when either fixing (hopefully) the stem rot situation or starting again.

By the sound of it, you are using quite a deep flood/drain system, and I had the slowly sinking plant problem in a similar set up. I found out that some of my pebbles floated, some sank during flood and drain, so the "column" of pebbles was unstable, with some pebbles sinking/floating, so the whole lot was shifting around, causing the plants to sink. Here's what I do:

Fill up part way with clay pebbles to around the final height, less the height of the cutting that will be below the pebbles when finished. Place some plastic mesh (doesnt matter what size the grid is, so long as its smaller that the average size of the pebbles) on top of the pebbles, followed by the cutting, followed by the remaining clay pebbles.

The mesh acts like a raft during flood, stopping the plants sinking as the pebbles more around. Its only really needed until the plant has put out roots to stabilise the pebbles. Doesnt really mather how big it is - I usually use something around 4-5inches square. Oh, and dont use mesh that floats (thats even worse).

In the past, I have even used those green kitchen scotch brite pads (new ones!) and they work OK too.

Also, how many times a day are you flooding - if you are flooding too often, the stem will always stay wet and hence the rot.

Really need a pic of setup to have a look, pic says a thousand words, just of the pot and how the stem fits in.

Hope you get it sorted matey.

If you have got root rot its quite probable all your plants will have it as there will be spores in the water. It is quite common in the warm summer months. As water warms up it holds less oxygen and gives pathogens a chance to take hold. Cuttings taken from infected plants will be infected too as root rot is systemic .

Keep water temps down to 68F. A regime of hydrogen peroxide and hygrozyme may help.

Cheers for the response guys; here's an update:

Well i've just pulled the plant it the stem had rotted almost all the way through. In the pics I have removed a few inches of pebbles so i could dig down and have a look. The roots smell fine and look as healthy as any i've seen. The stem (as you can see) is more than a little upset with itself. I think that what has happened is that the plant has been retaining too much water around the base of the stem. The babies came from an aeroponic setup so are in small rockwool cubes, then a small net pot. To install them into the system i placed them in a larger net pot to try to stop them sinking. It seems that a tight ball of roots has formed between the two net pots and i think that it must have been retaining water. The roots smell fine (and look amazing) but the rotten stem stinks... a lot!

The question is then is this a disease that the other plants are gonna get? Should I rush out and buy a UV steriliser before they all go belly up? And also what can i do about any other plants that I may find are experiencing the same problems? i'm seriously p***ed of with this and can't lose anymore babies.

Thanks for any more help guys.

Firstly get your water temps down to aat least 20C, at 25-26 water simply cannot hold enough oxygen, now matter how much air is bubbled through it. I would then start a daily regime of h2o2 treatment. As h2o2 breaks down it gives up its extra atom of oxygen directly into the water in your resevoir. it will kill off pathogens too. I would get some hygrozyme too, its good stuff and can be used with h2o2

Root rot treatment.

Get food grade 35% if you can, it hasn't got additives or get 17% from your hydro store.


Use 3% h2o2 at 3 mls per litre or 12 mls per gallon. Its recommended that you start at a lower concentration and increase to full strength over a few weeks. Use at every reservoir change and replace twenty-five percent (one quarter) every day. Example: In a 100L reservoir you would add three hundred ml's (3%) H2O2 when changing the nutrient. You would then add seventy-five ml's more every day.

dilute 35% h202 1 part to 11 parts water to get 3% approx

dilute 18% h2o2 1 part to 6 parts water to get 3% approx

dilute 8% h202 1 part to 3 parts water to get 3% approx

Thanks for the detailed advice alien. I'm looking into a chiller right now but anything at a reasonable price comes form China which i would expect to take a couple of weeks. I'll start using H202 tomorrow when i can buy some. I've never used it before as it shortens the lifespan of the enzymes i use. It has occurred to me that both of the plants that have died were 3" lower than the others. This has resulted in the water being higher in these buckets at feed time so the plants have sank more easily. The other plants have not had this problem. Both of the lower ones died! If this is the case is it still likely to be pithium and should i still take all of the relevant precautions?

Thanks for so much help guys.

It looks very much like it was the cause of your 2 plants dying, those stems were rotten. Ive seen plants started in rockool cubes that had got fairly big with the saturated cubes still attached for their whole lives with no problems. If I was you I'd presume you have pythium infection ( just to be safe)

H2o2 is very easy to use and will cause you no problems. Someone said to put frozen waterbottles in your rez, thats good advice but if you got a large grow may be impracticle, just try to get water temps down to 18-20C

Use something to accelerate root growth, I recommend hygrozyme because the manufacturer states it can be used with h2o2.

good luck

Chillers are expensive, if possible cover the water from the lights around the plants, would drastically help, or simply pointing a fan at the water would cool it 6inch from ebay 8 quid, price of chillers from what iv seen is emmense, most likely the lights warm the water and hence pythium has kicked in.

If one plant is effected and the plants also use the same water as infected plant then chances are assuming you have pythium that every plant is effected, not to say you wont get a yeild, but not as much as it would of been without damages roots which uptake solution and feed the plant which in turn increases yeild.

You can knock 3-4 degree's off with a fan, covering water which is under direct light can shave a few degree's off, cooling lights by facing a fan at them decrease temps if temps are to high, pythium is a bitch and only going to get worse, 10 new types per year are found and each time harder to combat.

Had pythium problems couple of times, really hard with recirulated systems to avoid partial pythium, or slight browning of roots, or full blown pythium which kills the plant, have to be clean, extremely clean, nothing in grow room which you do not need. Sterilise everything, never handle roots without gloves when transplanting, I use rubber gloves, generally everything has to be tip top and clean, full time from start to finish.

Although to be fair had to change systems before I got rid of pythium, it totalled my first grow almost completly, 6 plants destroyed out of 8.

Thanks for all the great advice guys. I've not been able to get any H2O2 today but it's first on the agenda tomorrow and i'll be putting them on a strict regime for the next few days. Today some of my other plants are showing yellow leaves with occasional blothches; these have died overnight so i'm seriously worried about the whole pythium thing now. I've had the res temps down all day by changing the water every time it gets too warm. The water had started to smell like an old pond but i'm thinking that this is perhaps due to the AN nutrients I threw in there a couple of days ago... they are gone now and not coming back! If anyone would like to tell me that yellow leaves in the space of 24 hours is nothing to do with pythium i'm all ears:)

Thanks again guys

I've added a strong mix of H2O2 and i've also attached a 400mg Ozone generator to an airstone and dropped that in the res. No update on the state of the plants yet but i know the res smells better already:)

often wondered about those ozone air pump things, let us know how you get on with it.