Plant die off at day 30 - never seen before - desperate for help

[crisco22]

Hi community,

I have a very serious issue. For the past year, every grow I have starts to die off between day 35-42, and by day 56 is so far gone that my yields (and quality) have become are approaching zero. I have tried everything and am hoping someone here will recognize the issue and offer some help. It has happened across several strains, across several rooms, and with seeds, new clones, and my own clones grown in rooms that were sterilized between grows. My first thought was a fungus, like fusarium, (and it still could be) so I have treated them all with a root drench of 3 different classes of fungicides when flipped to 12/12. They grow well and look amazing for the first 4 weeks, then top bud leaves start to wilt and dry up. During week 5-6 this RAPIDLY accelerates until the whole plants leaves die and only the bud is left green. At this point I try to harvest what I can, but its usually not much and of poor quality.

My next thought was ph, and the last run I have diligently kept it at 5.8... still happened.
Then i thought it was nutrient level.. perhaps a shortage of something they rapidly start taking up during the height of flowering, and thus take it from their own leaves when its not available. So, i upped my ppm from 1400 to 1800. This also didnt help. (started to see some nute burn but not too bad)

Now, I dont flush between reservoir changes but.. i havent for 8 years and its never been a problem. So unless something has changed I dont think its that. But again, open to any thoughts.

Here are the details:
What Strain is it? Multiple, sativas seem to be affected more though

How Many Plants? 15
Is it in Vegetative or Flowering Stage? flowering

If in Flowering Stage... How Long? 35 days
indoor
hydro
If Hydro, Reservoir size? 100 gal
If Hydro, Reservoir Temperature? varies with season, 75degrees
If Hydro, what type of Medium? coco
If Hydro, what type of Setup? ebb and flow

Size (Wattage) of Light? How Many? (2) 1000w hps
Is it Air Cooled? yes
Temperature of Room/Cabinet? varies by season, every attempt made to keep it 75(day) 70(night)
RH of Room/Cabinet? 50%
PH of Medium or Reservoir? 5.8
Any Pests? fungus gnats
How Often are you Watering? twice per day, from and aerated tank
Type and Strength of Fertilizers used? cyco nutrients, 1400-1700ppm
Size or Square Footage of Room? 8x10 feet

 

[Pdub721]

Re: Plant die off at day 30... never seen before... desperate for help

Hi community,

Now, I dont flush between reservoir changes but.. i havent for 8 years and its never been a problem. So unless something has changed I dont think its that. But again, open to any thoughts.

I have no experience with hydro but this sounds like it could be a problem to me. I'd let someone with experience chime in though.

 

[crisco22]

Re: Plant die off at day 30... never seen before... desperate for help

The thing is though, I have never flushed before and was always fine. In another room I have switched back to hydroton to see if the coco is the problem. Still too young to see if thats the case.

 

[Lester Freeman]

Re: Plant die off at day 30... never seen before... desperate for help

I have summoned a higher council.

 

[Lester Freeman]

Re: Plant die off at day 30... never seen before... desperate for help

I don't grow hydro, but heres my two cents.

A 100 gallon reservoir seems a little too big to precisely maintain a finely solvated system, homogeneously speaking.

But you say you've been doing it this way for 8 years...and its happening at certain days within the cycle. Consider what you are feeding them, surely you'd have to change nutrient lines over the course of 8 years. So it must be what you are feeding them, and in what quantities. This could be a toxicity issue rather than a deficiency issue. However, check your nutes for how much metals are in them. Also consider recalibrating your pH meter.

In the mean time check out this link Cannabis Plant and Pest Problem Solver - Pictorial


Also if you've been growing new / different strains, not each strain has the same metabolic requirements..

 

[crisco22]

Re: Plant die off at day 30... never seen before... desperate for help

You're right, I have changed Nutes over the past few years and am going to switch back to GH or Cutting Edge asap. I dont remember exactly when this issue started but it could be around the time I switched. I will say though that its getting progressively worse, which is why i questioned nutrients and blamed a fungus. I feel like I have tried everything, and none of the troubleshooting guides match what I am going through.

also, i have a new ph meter that I check the calibration on every 2 days just in case.

 

[Lester Freeman]

Re: Plant die off at day 30... never seen before... desperate for help

With a reservoir size that large, it makes it difficult to properly flush the system. The plants use different elements in different amounts, so when it was done with what it needed, it set the rest aside, and it slowly accumulated up until day 35-42, the balance of the elements was lost, and having a higher concentration of one of the elements probably prohibited the uptake of various other elements.

Unfortunately, we normally flush our mediums (soil or hydro) with some factor of the total size of the pot (or res), so for my 5 gallon pots I'll flush with 15 gallons of water.

It would take you 300 gallons of water to adequately flush the system.

 

[crisco22]

Re: Plant die off at day 30... never seen before... desperate for help

With a reservoir size that large, it makes it difficult to properly flush the system. The plants use different elements in different amounts, so when it was done with what it needed, it set the rest aside, and it slowly accumulated up until day 35-42, the balance of the elements was lost, and having a higher concentration of one of the elements probably prohibited the uptake of various other elements.

Unfortunately, we normally flush our mediums (soil or hydro) with some factor of the total size of the pot (or res), so for my 5 gallon pots I'll flush with 15 gallons of water.

It would take you 300 gallons of water to adequately flush the system.

Let me clarify a little, the res here is used by 3 trays of 15 plants, and is changed every 10 days. So there should be no buildup or imbalance in the res itself.