Thoughts on root zone ventilation, drowned seedlings, hydro, RW, hydroton

Stumbled across this site a few weeks ago and have been absorbing knowledge since. There is an absurd amount of information on this site...

I'm a n00b to hydro and started some seeds in 1" RW, eventually transfered into hydroton on a E+F table. Got some bad info from another site and planted the RW too deep -- 1/2 was submerging each flood (RW drenched...), although it took me almost a week to finally read otherwise and fix this (pulled the RW about 3/4 inch above waterline).

By that point, my plants showed signs of drowning. Now I know - never fully wet RW! Also, don't squeeze it if it does drench...destroy the air pockets

I actually connected all the baskets and hooked up a fan so that the root system can be ventilated and is dark (this works amazingly well) in an attempt to dry the RW out and get some oxygen down there...but I don't think the roots have even grown out of the hydroton enough to really care yet about ventilation -- it's been 3 days since I raised them out of the water (drying the RW was a good idea though, and I think that stopped their drowning). I don't think the roots have reached the water table 3/4" below, yet. So, I have been doing light top-feeds on the plants to encourage further downward root growth, as well as running the root ventilation fan occasionally to keep humidity high and hopefully entice the roots downward. I may continue to use the root fan system, too...humidity, adiabatic cooling for roots, cover keeps them dark...

My questions:
- How slow is this growth? The included pic is Day 16 since seeding (Day 13 since ground break) growth...I think they are basically stunted beyond belief from the over-watering
- Does anyone have experience with blowing air into the root zone? Circulating or venting air? I was thinking about doing this right after I flood to increase humidity and dry the roots out a bit to start oxygen exchange, and then maybe once more for 15 minutes in between the floods...Doing 3-4 floods a day.
- Lights at 24/0 or 18/6 for seedlings?
- Is there anything else I can do to fix this fucking mess of slow growth?

Luckily, these aren't great seeds...just really a practice run to get the fucker warmed up. I have learned a lot in these past 3 weeks since I started, mostly on this website. I haven't found much on venting the root zone (only on injecting oxygen, but even that is only briefly mentioned) or on how to get your seedling to travel the distance from the RW to the flood waterline. Also have found people who flood once an hour and others who flood once every 6 hours...My hydroton is in baskets not spread out, so I was thinking I might be able to get away with more frequent flooding if I use the fan to ventilate and avoid root root. Thoughts?

ANY thoughts on root zone ventilation: frequency of ventilation or timing of ventilation, et cetera, are appreciated!


Day 16.jpg

:blsmoke:
 

Stonefree69

Member
I'd say flood for 15 minutes 2-3 times per day and only when lights are on. So that's every 5-8 hours. As they mature you can go up to every 3-4 hours for 15 minutes. With rockwool you might even want to water 3-5 minutes duration instead of 15. But the hydroton should help it dry faster.
 
RW is above the water line, so it doesn't get wet. I've been watering 4x a day in the early stage and using the fan a lot, they have been doing well, not over watered. Thanks for the tip
 
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