Grow Mediums Seedling mass genocide, need help

[Phobos]

Hey guys,

I really need some help. If there is a badge for being a seed serial killer, please give it to me like now...

It's been 2 months that I try to grow some Mephistos and something is f$cked in my process but I can't find what. I do like I've always done since +4 years but it seems that my method is dead.

I grow in rockwool cubes. My germination process is the Mephisto process (dvd case). I ain't got problem at germination. My problems comes later.
So after having my seeds succesfully germed, I put them in the rockwool cube (small one) then I put that small cube in a bigger one. I put my rockwool cubes in a 5.5 PHed water for few minutes.

Seedling are growing but after 2-3 weeks, they ALL die. Their height is always the same (3 cm) and there roots are fragile. The cube is full of roots but it seems that they don't want to hit the water like my previous plants.

I've sterilized the room, sterilized the hydro system (https://www.platiniumhydroponics.com/gb/9356-platinium-hydrogrower-40-40x40x28cm.html) thinking it was maybe some damping off, nothing changed. This is the first time I use this system, before that I had something similar but much bigger.

My setup changed lastly. Maybe my problem comes from this. I have a Mars Hydro TS1000 that I've used only one time, also with a weird start. But the plant grew really well.

For info, I put the lamp at 60cm (22-23 inches) dimmed at 50%. The guy at the hydro shop told me that a possible reason was that the lamp was too close. Tina recommend 50-60% at 60cm so I'm on the range.

I feed the plants with some Canna Aqua vega. The feeding level is 7ml for 15 liters. I've tested some feeding right after the seed sprouted (was actually doing like this before without any issue), feed them after a week, not feeding them at all, watering only one and see the 3 others, giving a lot of water to another one, feeding them with a drop of nuts, feeding them at 5ml / 15 liters... Nothing has change.

I thought maybe the problem came from my canna aqua vega bottle date wich is passed since 2 months but the product seems clean, no weird odor... Clay peebles are new and stabilized at 5.5. Important thing, I've never checked the PPM so I can't incriminate water, even if that is for me the biggest culprit.

When in rockwool, I water every 4-5 days (I check the rockwool moisture by lifting).

As for the environment, I try to stay between 23°C and 27°C (73°F and 80°F). Humidity at 70% (more or less 20%)

I've ordered some FastBuds, will germ them at the end of the week with :

- Some bottled water because where I live water is full of "cleaning" products, plus those bastards added some more products in water with this covid show

- Rockwool all night (instead of few minutes) soaking in a 5.5ph water

- TS1000 dimmed at 25%, distance 60cm : )=> Saw a post where Tina says for seedling : 50-60% at 60 cm is good so that is not the problem

Sorry for the long post guys but it's not good to feel like you've lost your growing mojo... And I won't tell you how crazy I am loosing all those precious seeds...

If someone has an idea...

 

[Simplicio]

Almost every hydro issue I've had is due to too much food or light.
I keep my hydro close to pH = 6.0 seed to harvest.
Exceeding EC=1.2 during veg, or EC=1.0 during late flower gives me problems.
I've got some ~ 8 week autos that don't like more that EC = 0.95

There is an easy solution.
Too little food and/or light will reduce harvest.
Too much will injure plants, reducing harvest even more.

Err on the side of too little, and you should be fine.

The food issue is especially easy.
If ppm rises from day to day, plants want less food.
If it falls from day to day they want more.
Mine rarely want more.

 

[DCLXVI]

@Mañ'O'Green is a hydro expert.

 

[Phobos]

Hey Simplicio, yes, when everything is on tracks I always stay on the "too little" side too. Better doing this plus this is one of the many things I've learned here on AFN.

For me the hardest part of growing is and always was the beginning. From seed to the 2-3rd node. When they've past the 3rd node, they really live there lives and I know everything will be smooth.

 

[Phobos]

@Mañ'O'Green is a hydro expert.

Thanks for tagging him

 

[Bob's Auto's]

Have you calibrated your pH pen? and please do check the batteries, I've had an issue with that some time ago.

 

[Phobos]

Have you calibrated your pH pen? and please do check the batteries, I've had an issue with that some time ago.

Yes, PH pen calibrated every 2-3 weeks with a ph 4 solution + a ph 7 solution. Haven't checked the batteries (the pen tells me when batteries are dead) but will do.

 

[Animatey]

Not sure if this is your issue, but a long time ago I had a case of rockwool starter cubes that I left in the closet for months and it got contaminated by some kind of fungus.

I could literally see weird spores forming on my seeds after placing them in those cubes. I eventually threw them out and everything went back to normal.

After that I started to soak my cubes in distilled water and then microwave them until they boiled (let them cool before doing anything with them).

I now instead do my initial soak of cubes with RO water and some beneficial bacteria/fungus (recharge).

Seeds and young plants are highly susceptible to diseases, and it's possible that's causing your issue.

Good luck, hope you track it down.

 

[Phobos]

Hey Animatey, I thought that was also possible. Generally I buy those cubes and I use them in the week. Maybe they get contaminated at the shop (they are on a shelf, waiting for clients).

Don't have a microwave but will let them stay a while in some boiling water.

Anyway, thanks a lot for your ideas.

Will of course let you all know if there are good news, will do my next test at the end of the week.

 

[Phobos]

@Animatey, so after you've micro-waved your cubes, how long do you let them soak in RO water ? All night ?