HYDRO NOOB: Seedlings Not Growing +REP

Hey RIU,

Im new to hydroponics and I have 7 Critical Mass seedlings growing.

I germed about 3 weeks ago and placed them in rockwool cubes.
I have a 96W T5 for light and Im using GH nutes.
The room was pretty hot for a while (80-85F) but I have gotten that under control
temps now aroud 75-80F.

LIGHTS: 96W T5 20on/4off
TEMPS: Around 78F
NUTES: General Hydro Flora
I feed about once a day PPMs around 450 and pH 5.5-6.0

They were growing good for about the first 2 weeks but no growth since,
I can see roots in the bottom but not many.

Anyone with hydro experience please help.

they didnt need nnutes when u gave it to them
typically one would wait ttil the plant has 2 sets of true leaves before adding nutes.....even then, only adding a light dose
my advice is to flush those little cubes and use plain water til new growth looks good,then start ur feeding lightly

Your probably best to make sure that the bands or not too tight round those cubes so your not strangling the little tap root.

If they were my plants I would have a layer of Perlite at the bottom beneath those cubes so that when the tap root does emerge it can go into the perlite and get some shelter otherwise its probably just going to get dry and "air prune" itself -

The strength of the nutes your feeding are a tad bit strong. Take into consideration that I am 2 weeks into 12/12 and I am only @ 600 ish ppm -

In hydro try and always think "less is more" you can always add more but never take away if things start going south.

Your babies dont look too bad to be fair so remove the bands or make sure they are not too tight, get some perlite below and give them a water. Make sure the Perlite gets a bit of the moisture also..

#1 problem with rockwool is you can get it too wet. Try letting them get drier. I have found in rockwool that you only need to water every other day or so. With those rubber bands I would think it would further decrease the air/water ratio.

If the rockwool is not working out for you I would try to use root riot cubes. IMO they are easier to use for noobs starting out in hydro.

initially i broke the cubes in half trying to put the seedling in thats where the bands came from and thought i had a phosphorus diffentiency thats the only reason i started using the nutes. ill go back to tap water and remove the bands hopefully that will help.

also should i use a heat mat or not.

thanks guys

I personally use a heat mat with seedlings and clones but if you do I would raise them up off the mat and add about a 1/2 inch of water at the bottom. Make sure the rockwool stays out of the water, it is really bad about getting water logged and drowning plants.

when u say 1/2 inch of water at the bottom do u mean inside the tray with the cubes in contact with the water

inside the tray but with the cubes raised up not touching or just barely touching the water.

ur drowning those seedlings.rockwool soaking wet.let them dry out a bit before any more watering.

Honestly it's too much water. Also at their stage I wouldn't feed anything except a root excelerator. And that only at 20 - 40 ppm. Once good strong roots developed I'd place in my grow medium. Hope this helps you.

Ps I use bcuzz root, it works really well and smells yummy!

yep your suffocating those roots =slow growth

Ok so heres what I did with all the advice I got.

On 8/14 I took the old soggy rockwool blocks and carefully pick off all the old rockwool so all I had left was the bare root (the roots didnt look that good they were turning brown in spots). I then placed them into new rockwool cubes that were prepped properly. Ive been giving them distilled water with a root excell at 30ppm 5.8pH.

Im seeing some new growth now but not very much.
The pics are from 8/18 4 days after I made the switch.

My concern is the older leaves are turning white I only have a 96w T5 and its about 24" above the plants.

Im not that worried but if anybody has experiece with this Id really appreciate the input.

I also threw some pics from my last grow 400HPS bagseed in soil came out wonderful.

bump bump...

Get the T-5 in another foot with a little ventilation. 12" is safe. Keep the rock damp, not dripping wet. The old leaves are history. I am worried that you saw brown roots: That means death, however you say you have new growth so you probably saved them

Put them in the hydro system and let them grow the plants will comeback and take the bands off when you can see the roots its time to goto the system 450 ppm is to high lower it to 200 ppm they will grow the ph is good good luck...

I took the bands off once I replanted.
The roots are looking much better so I dont think thats the problem.
Ive only been giving distilled water with a root excell ~30ppm maybe the need some nutes could this be why the leaves are yellowing?
I didnt want to give any nutes because of fear of nute burn should I maybe give a low dose of nutes?
These are new pics just taken right b4 this post.
Let me know what you guys think.

im not a hydro person, but i would assume with the large amounts of nutes at first, then nothing, they are probably still overcoming the original issue. i would wait a couple days before doing anything to them.

they may well just be stunted a bit from the over watering, if the roots are growing well again then give them some time and the plants will recover. i transplanted a stunted little one once that took a month to recover lol but hopefully yours will come back sooner then that. and im with everyone else on the overwatering of the rockwool, i use it myself and have made the same mistake, your lucky you didnt get damping off disease. with rockwool there tends to be a transition in the rate of watering where at first they need almost none, then the small cube will start needing alot, then transplant to bigger cuve and water like once every 3 days, a week later watering it daily. if you have a tough scheduel that makes keeping them watered tough you can put a little hydroton in your tray and lay the cubes on top of it and leave a little standing water below the surface of the hydroton, it will wick to water the cubes but wont overwater.

Skip the rockwool next time, too many issues to be had with them (i.e. ph, water-logged, etc).
Get some rooter plugs (coco by-product).
I soak my plugs with ph'd water, and squeeze the excess water out. You don't want them dripping water.
When I see a tap root, I plant the seed into the plug (not too deep/enough to cover the seed).
I then sit my plug into my net pot, on top of 2 inches of hydroton, and fill in around the plug but not covering the top of the plug.
I have a seedling standing up withing 48hrs.

Hope this helps !
See my grow thread for pics of new seeds in plugs.