This has now happened to me now for the first time and twice in a row. My seedlings pop up fine and seem very healthy and just within days they damp off. This one damped off a few days ago so I tried putting it in water now: And this one damped off today, must be just some hours ago: What's happening? Can I save them? Straight coir, temps fine, 24 hours LED nothing I don't usually do. Any ideas?
First off, no more straight coco. Coco works good, but you use it with 1/3 perlite and do drain to waste system, so have a catch basin underneath to catch the water. Second off, you need to condition coco with a good source of calcium. Lastly, to prevent damping off, or iow, pathogenic attack, germinate and grow your seedlings in 1% hydrogen peroxide. You can make this up using OTC pharmacy grade hydrogen peroxide (3%) and diluting it to 1% (ie. Add 2L of water to 1L of 3% peroxide = 3L of 1%). That will kill the pathogenic organisms and provide ample oxygen to help your seedling along. I recommend looking over this site: https://www.cocoforcannabis.com/
But this setup usually works OK for me. It's just weird that the seedlings pop up fine and look healthy and just kinda die some days after. I add gypsum to coir for calcium and my nutes which I add later on contains calcium too but it shouldn't be the cause of death. I also treat my coir with a lot of boiled water to kill off potential pests.
Thanks! After some more reading I suspect I didn't make my coir fluffy enough this time out of laziness. I'll try again with fluffier and drier coir. Do you think I should pasteurize it again by pouring hot water on it? Rooters look safer ofc but I've done this so many times successfully before so it feels unnecessary ATM. But maybe if I waste more seedlings I'll consider it.
Can coir be invisibly infected or contain pathogenic organisms that can't be killed by pasteurizing using boiled water?
this seems obscure; I've not heard of anyone boiling coco coir until now. This is not the suggested practice for preparing coco. I suggest you look over the site I recommended and use the proper beneficial organisms to inoculate your media.
I do it mostly to prevent fungus gnats but it's not really needed. I've had success both with and without pasteurizing but this summer I experienced fungus gnats for the first time when I tried new type of coir that I didn't pasteurize. It should not be harmful tho. Coir is like nothing. It has nothing, it just holds a lot of water. When growing mushrooms for example, it's standard to pasteurize it using boiled water.
I hear yea; when I used soil that's from outside (for other plants), I place all the soil in a big black (mason jar) pot and bake it for about an hour.