Something like this:
Or this:
I’m trying to get away from rockwool starter cubes and looking for an alternative for starting about 30 seeds at a time in coco.
I think these trays are intended mostly for soil, but wondering if anyone uses something like this for coco 
Are these the trays that disintegrate when you plant them or you have to remove them manually?
So one of them would disintegrate, the other is plastic.
I was thinking maybe something like this, where it’s plastic but reusable:
No matter what I wouldn’t put any of them into the coco, even the biodegradable ones.
I can’t speak to coco specific because I use peat but off the top of my head I see no reason why it shouldn’t work as long as you pH and buffer them (this is all I know about coco 
)and keep them damp.
I’ve done it in egg cartons before and found handling micro rootballs for transplanting a bit of a pain. Now I use 1L starters as my preferred method.
Best of luck.
Yeah I am basically going to finish in 1L pots… I thought about starting them in 1L pots BUT I need to do another test run first and make sure the sprout rates look good. That’s why I was thinking maybe using these tiny hellish things so at least I could do a test run first with seeds I don’t care about, and make sure my sprout rate was at least 90%.
I think this is a good idea.
I’ve had good success keeping the seeds soaked as well as keeping them moist so I wouldn’t worry too much about it.
But if you have practice seeds by all means use them to your advantage!
In my rockwool cube test I only got 9/12 to sprout in about 90 hours.
75% is not quite high enough… I’m close to 100% with paper towel method, but I have had seed that germed in a paper towel not sprout in coco/perlite
It’s been a while since I messed with coco so I’m not 100% sure why that would have happened, but it’s possible that I lost the seed under some perlite. Not sure…
Hopefully I can run another test and get 90% or higher using paper towel → 100% coco.
Thanks for the help!
I use small grow bags that I fill with coco and they work amazing. When ready you just plant them in their new pot bag and all.
i use starter trays. the nice ones are worth splurging on, i use these. head up though coir sometimes has fungus gnats right out of the bag. theyre not a problem for large plants but can eat young seedlings roots sometimes causing trouble. I sterilize my coir in a pressure cooker for 30m @ 15psi (only for seed starts)
Nice, thanks for the tip!
I have a brick of coco in the oven right now at 270F, and it will be in there for 8 hours 
that should work. you probably only need to cook it until the core has reached 170f for ~20m. technically we only need to pasteurize not sterilize. anyhow. i use one of these with a pot that i fill with coir and place entirely inside.
edit: just noticed amazon is selling them for $1250. thats some crazy person trying to sell their stuff at a markup. these go for about ~$350 new. i have two of them but realistically youll only need one
The brick is pretty massive (5kg) so I’m not sure how long it will take the center to hit 170f.
I’ve never had a bug in my grow room though (knock on wood), so I’m trying to keep it that way if at all possible… One way I keep the missus OK with having an indoor grow is keeping it bug free.
8 Hours is probably overkill though…
I have those starter pots that degrades and had not good experience for soil.About Coco,I didn’t use Them,instead,I Just use Little plastica cups where I cut holes like those:
Since I start to fertigate as soon as the seed pops up I have to skip those pots because they destroy when at contact with water,Imagine how they would become in a 2x watering at day till runoff…no way.I transplant when roots goes outside of the plastic cup
Not me. I start seeds in solo cups filled about 2/3 with coco, which I can keep going for upwards of 30 days. I’ve found that using plugs or pucks or whatever, results in needing to be transplanted sooner rather than later.
you should be hydrating it prior to pasteurization else the oven will have trouble getting it to temp evenly
Normally I break it up first, but that’s why I figure I’ll just leave it 8 hours.
I’ll check it with an IR thermometer when I take it out and break it open
gotcha. the steam is really important for successful pasteurization. in the future, definitely consider hydrating it and tossing it all in a large oven tray. that being said the issue with gnats in coir isnt huge. most bags come clean, the bricks are even cleaner since they are “sterilized” in a sense when theyre compressed. i lost a couple expensive seeds then went overkill with my regimen to never let that happen again
Yeah I understand wanting to go overkill to be safe lol 
Hence 8 hours at 270 :X
I would go higher, but I read stories of peoples coco bricks catching fire above 350 degrees.
I figure 270 and 8 hours hopefully gets me 170 in the center for some period of time.
I will definitely check out the pressure cooker if I keep going with coco. I normally run in rockwool, but have been wanting to do some experimenting in coco/perlite to see if it can be more forgiving with automated watering times in situations where many plants are on the same timer.
A probe thermometer might be better that the gun because they guns only measure external temps 
Yes, I have a ton of those flimsy trays, many I need to double tray because they have so many cracks… I don’t want to throw them away because they are non-recyclable plastic 
I go back and forth between these trays and rockwool cubes… I prefer the cubes but the coco is so much cheaper that I have no problem switching… but I do prefer the solid base the rockwool forms over the loose coco media that gets everywhere. I soak my seeds in water with a small amount of peroxide until the root emerges and then transplant to the pure, freshly-buffered, coco with only cal mag in it and place the trays in a covered container/domed tray to keep humidity high until the tip breaches the soil so there is enough moisture retained in the coco that the seedlings don’t wilt. Then I open up the container and let them grow away! When the coco needs watering I water with no more than 300ppm/0.6ec until they get transplanted to larger containers. I have never heard of anyone getting fungus gnats from a dehydrated brick of coco, only from bags of loose coco. Good luck, and happy growing. 
