Stem Rott? What can I do?

[Sinisterzane]

Hi all,

I have a couple of NFT tables with vert lights down the middle

I am in trouble as it would seem I have stem rott and not sure what to do. The very bottom of the stems for about 1 - 2 cms have reduced in size by up to 50%
....it is so bad some of them have fallen over and ive had to strenghen them with garden twine

Both the tables are completely covered with lightproof plastic and well sealed they are covered in such a way little or no air can get in. the blocks are totally soaked

This morning I have changed the NFT pumps so they come on 15mins every 6 hours (they were on 24/7) and pulled back the cover off the ends of the tables to get some air at the roots

The roots are a perfect white colour and are out and all over the spreader matts

PH 5.8
EC 1.0
3ml per litre of Rhizotonic
0.5ml per litre of Oxygen h2o2
Room temp 26 degrees centigrade
Room humidity 40%
Water temp 21 degrees

 

[Rainbowkid]

Well to me it looks like what ever medium is <rock wool?> surrounding the stalk is too wet and harboring bacteria.. Here is a wiki article on damping off http://en.wikipedia.org/wiki/Damping_off . I would suggest dropping the water level in your nft there should just be a small film of water and the medium should not be touching it the roots should hang down into the water. hope this helps RK

 

[Bag]

id say let them dry out , ive only had experience with stem rott with seedlings and when i got it i got it bad, lost many many seedlings for about a month 1 time, i swear it was lunar cause a friend had the same problem at the same time. i think i got it from over watering. good luck.

 

[Sinisterzane]

id say let them dry out , ive only had experience with stem rott with seedlings and when i got it i got it bad, lost many many seedlings for about a month 1 time, i swear it was lunar cause a friend had the same problem at the same time. i think i got it from over watering. good luck.

Thats what im thinking as everything seems to be bang on stat wise

The cubes are soaking to the point when i touch the tops of the root riots (root riots in 3" blocks) it soaks my finger

Ive got them on 15mins watering every 6 hours now as I dont want the roots to dry out on the spreader matt

also because I have covered the whole of the NFT's with plastic I dont think enough air is getting at the cubes and roots....ive peeled the cover back at the pump end now

 

[ZZTops]

They look too far gone to just dry out IMHO...

I'd clone them and start over with better circulation, high temps...

Or transplant into soil and bury the effect area 2" below the surface, this will grow roots about the affected area...

Or use another 3" rockwool cube, make a cut on one side and slide/stack on the old one. again creating roots about the affect area...

On lighter cases I've used weak Chamomile Tea to water, then sprinkle cinnamon on the affected area that worked...

Here's wishing you good luck what ever way you go...

Edited: That's Chamomile Tea, not Calamine Tea...

 

[Sinisterzane]

They look too far gone to just dry out IMHO...

I'd clone them and start over with better circulation, high temps...

Or transplant into soil and bury the effect area 2" below the surface, this will grow roots about the affected area...

Or use another 3" rockwool cube, make a cut on one side and slide/stack on the old one. again creating roots about the affect area...

On lighter cases I've used calamine tea to water, then sprinkle cinnamon on the affected area that worked...

Here's wishing you good luck what ever way you go...

Hows about putting cotton wool balls over the bases of the stems soaked in h2o2? and changing it so it waters once a day for 15 minutes?

 

[ZZTops]

Sin...

h2o2 is an oxidizer and kills indiscriminately so too much and every thing is gone, so go light if you chose that road...

I'd do the weak Chamomile Tea watering and Cinnamon dusting myself then clone/re-plant if it did not work out. Might want to support the plants as well so they do not fall over...

They look healthy so saving them should be a breeze just going to cast you some recovery time...

 

[ZZTops]

Rockwool normally only takes 1 or 2 waterings a day in a flood and drain system but I do not know your situation...

Here a Google Link on Damping Off and Chamomile Tea...

https://www.google.com/search?q=Cha...s=org.mozilla:en-US:official&client=firefox-a

 

[Sinisterzane]

Can I take cuts off then? then destroy them?

 

[greenmatter]

got any physan ? i've seen some pretty fucked up plants saved by spraying the stalk a few times a day (you really need to hose it down) ........... if you are going to clone those the physan might be good to have around anyway. whatever rot they have is gonna love it in a humidity dome

 

[ZZTops]

Can I take cuts off then? then destroy them?

Yes... Or do the whole plant, they do not look all that big...

 

[Sinisterzane]

Just had a proper look at them...

Theres 17 in total and can safely say at the moment 5 have no chance

The other 12 have the beaver ring round them just above the cube but below the ring the stem is the same size and a healthy green colour like above...However when I push the root riot apart a big the stem thats inside is a healthy green colour but with whiteish dimples on it?

Either way im fucked as I cant go throwing the other 27 in there and the same thing happens to them so it looks like a kill and properly clean job then replace the fucked 17 with new seedlings.

Need to establish what the cause of this was though. I put a proper thermometer in the water earlier and its 28 degrees!...the plastic on top is sort of acting like an oven so ive moved the lights up about another foot

The rockwool cubes are so wet they are almost falling apart...I think its a combination of heat, massive overwatering and lack of ventilation due to the plastic sheet being pulled over the whole system and clipped down with 20+ fold back stationary clips so theres no where the air can get into the roots...

 

[PuReKnOwLeDgE]

I have saved plants 30 times the size of that, that looked alot worse. Dry out the stem and keep it dry. Also, watch your rootzone temps this is the 4th stem rot thread or case I have heard of recently. I use cotton swabs and alcohol, and also physan 20. Dab the cotton swabs on the infected area daily until they are looking on the up and up. The reason I think these plants are perfectly fine and saveable is they don't look wilted yet, meaning the water transport system has not yet been cutoff. DRY them out, get good air movement on them, treat the wound, check your rootzone temps, check your humdity, stop saoking everything the plants look pretty wet in the picture.

 

[Sinisterzane]

I have saved plants 30 times the size of that, that looked alot worse. Dry out the stem and keep it dry. Also, watch your rootzone temps this is the 4th stem rot thread or case I have heard of recently. I use cotton swabs and alcohol, and also physan 20. Dab the cotton swabs on the infected area daily until they are looking on the up and up. The reason I think these plants are perfectly fine and saveable is they don't look wilted yet, meaning the water transport system has not yet been cutoff. DRY them out, get good air movement on them, treat the wound, check your rootzone temps, check your humdity, stop saoking everything the plants look pretty wet in the picture.

Thanks for your reply mate...

As I see it after doing lots of reading on the net the problems are from the below

Overwatering : for 48 hours or so the nft pumps were on 24/7 I recently removed the plastic from the rockwool cubes also (I had left them on)...I looked at them after 24 hours with my eyes but didnt examine them and was looking at them on a camera amazed at how fast they were growing. After 48 hours I went and had a look and saw 3 of them had fallen over so I examined them then propped up the bad ones with ties..im now drying them right out and am even trying to get away with watering them for 15mins every 24 hours but will keep checking how wet the roots are and rockwool

Too much humidity: Its only at 30-40% so i cant see this being the problem

No airflow and ventilation: This is a possibility as I have a 10" fan on the end wall thats blows the mixed hot or cold air into the canopy only...I have a couple of 12" osciliating fans but the only way I can position them is so they blow against all the plants and the nearest one is to weak to take the pressure even with the fan on its lowest setting and a speed controller on it

Cross-contamination and/or unclean growrooms: All the kit is brand new and I gave it a wash out with h202 also

high reservoir temperatures: It has been at about 21-23 degrees C but earlier i noticed it was at 28!...this has been due to the lights being pretty close to the nft's and the light proof plastic covering them acting like an oven..so now ive moved them back up

IF it were to sort itself out the trouble is im not sure due to it being an infection it might come back!? If this happens when im well into flower with 40+ on the tables i will be totally screwed..once its gone and they are bigger do you think it can come back?

Two of them are looking pretty droopy now so i think its starting to fuck there watering system...these two however are the first ones in the row on the tables of which are right next to the delivery pipe tube so basically these two would of been getting blasted..one of them has shriveled lower leaves



I wont be able to get physan 20 at my local hydro shops as I think its an american product?

I have heard they can be treated with h202?

Thanks

 

[Sinisterzane]

Hi all...Someone on another forum had his first 4 grows wiped out with this same stem rott he was using NFT and seedlings also.

He experimented with various watering techniques etc of which made no difference until he lowered his EC right down then built it up slowly with the water on 24/7 and the blocks straight on the spreader matt then he had success...he did this because he noticed it didnt happen if he put the established blocks straight on in ph'd water. So in my case my EC was 1.2 so they had gone from EC 0.4 (EC of plain tap water) to 1.2. Do you think its possible this is the reason? Perhaps its strain dependant? I allways thought if you over nute them the first thing that happens is you get tip burn etc?

I also had Oxygen h202 at 60ml per 100 litres in the mix........

Tonight I am going to try hitting the blocks with a grow EC of 0.8 (they have only had ph'd water so far and the roots are well out of the blocks now) and leave them in the propogation tent?.......

 

[Sinisterzane]

ripped them all out and gave everything a damn good scrubbing in h202 today and have double rinsed everything...all the cleaning materials (towels, scrubbers, buckets etc) were bagged up and binned also

I have 12 in 3" cubes that are bursting out the bottoms...I gave them a 0.8 EC feed of grow yesterday and today they have gone wild

These 12 are currently in the propogation tent with a T5 above them sitting on a tray

Today I got some tile spacers and stabbed one into each corner of the bottom of the cubes avoiding damage to the roots as much as I could. An hour ago me mate phoned me to say now that the tile spacers are in and the blocks are off the floor of the tray by a cm or so the roots have started to hang down and touch the tray of which is bone dry.

I also put tile spacers in the bottom of 15 more 3" cubes of which I put the smaller rooted cubes into yesterday so they are not out the bottom of the 3" cubes yet

I am trying to get the roots to hang off the bottom before I put them on the nft's.

Should I put some water with a 0.8 EC in the bottom of the trays?...the propogation tent air temp is 28 degrees C which would mean this water would be at 28 degrees pretty quick I reckon...im asuming the roots would try and sit in this water? Im not sure if just leaving them to dangle dry for 2 days would make a difference?

Thanks

 

[Sinisterzane]

I think the damping off is starting again with the new 12...

Ive just noticed a couple of them hve very fine pin point size white dots at the very very base of the stems where they are touching the tops of the rockwool....they rub off when I touch them so it looks like some kind of fungas..a couple of them have come out the blocks at an angle so I can see it more on the ones where the stem should be under the rockwool line

water temp 18-22
ec 0.7
room temp 26
oxygen h202 in at about 0.5ml per litre

The nft pumps are on 24/7 and theres tile spacers in the bottom of the 3" cubes that raise them off the spreader matt slightly but the cubes are soaking

 

[Sinisterzane]

Just tried to take some real close up pics but the camera goes to blury...heres some long range pics...the white dots/specs are right at the very bottom and should in effect be below the rockwool as I have to bend them slightly to expose the specled bits

They have been on the NFT 6 days and were 13 days old from splitting before they went on

 

[Sinisterzane]

its started again on 2 of them...a ring round the bottom of two plants...With the rest the section of stem between the top of the rockwool and the first set of branches is thinner than the section of stem above

I havent seen any difference to the above in the last 4 days although they are growing real fast up top and lots of new roots developing

Is it normal for the first section of stem to be smaller than the next section of stem? I am asuming this part should be the thickest part?

Going to let them run for another week and see what happens whilst im waiting for set no 3 to get big enough to go on...this next set are going to be 1" cubes inside net pots with a row of clay pebbles along the bottom and packed in round the sides with pebbles...they will sit straight on and the pump will run 24/7......EC will start at 0.7 (background 0.4)

 

[FRIENDinDEED]

Well to me it looks like what ever medium is <rock wool?> surrounding the stalk is too wet and harboring bacteria.. Here is a wiki article on damping off http://en.wikipedia.org/wiki/Damping_off . I would suggest dropping the water level in your nft there should just be a small film of water and the medium should not be touching it the roots should hang down into the water. hope this helps RK

exactly what I was thinking. never did like rockwool/coir for that specific reason. when I do soil runs I always water around the stem never directly in the stem area