2.5 weeks old sad and pale seedling

[MrMiguardi]

Hi Guys!
I am an Italian first time grower and i need to pratice with Hydroponic so i'm growing some Hemp Seed (no thc in italy... for now) in an RDWC system.
4 bucket + 1Res 75L total, 2 Mars hydro SP3000 at 10% power, 1.2x1.2x2m grow box, air temp 21°C, water temp 18°C, using ATAMI fert. Hydro A+B, Atazyme, Cal Mag, Ata clean. 410ppm 0.810EC

The plant had some stress this week since i've got some foam and bacteria probably from organic nute or bacteria in the tube or dirty and old hydroton, resulting dense white foam, ph rising to 6.8 and cloudy water.
Changed all the water, crubbed with bleach, flushed e refilled the system after some initial foam the next days all seem to be ok and after some trouble Ph is stabilized at 5.85 (probably ph fluctuation from the clay pebbles though i washed it 3 time) and the water is not cloudy anymore.

To prevent light in the bucket i covered the pots with some mylar disc but some plant seem to not like it resulting clawed bottom leaves ad a generally sad apperance.
Added to my grow room a Secret jardin fan and a serious humidifier since %hum fallen to 40% some times and with no fan inside the box probably the % was even low in some part of the grow box.

From Sunday one of the plant has droopy or clawed bottom leaves slowly turning pale/yellow cotiledon seems are yellowing but maybe was normal.
On plant has pale bottom leaves with a dark zone on the tips and the other plant seems fine with only some clawed bottom leaves.
Tried to remove di mylar disc and some leaves seems to feel better but i feel worried for the pale leaves.
Generally this week plant has stunted grow but one of them seems to be on the way to the veg. stage.
Every plant has access to the same solution, oxigenated and recirculating, same light, same temp (and same hum from yesterday) ph are stable also from yesterday.
I don't think is overwatering but probably underwatering or nute deficiency? when the first root has touched the water i didn't sprayed the plant anymore but maybe it's to early so a few hours ago i sprayed them with the same solution.
Nute burning? maybe 410ppm are too high but one of the plant seems to don't have the same symptoms.
Any idea?
Thx in advance!

 

[MrMiguardi]

 

[013]

They are so cute at that age…..soil guy so not much help on hydro but wanted to get ball rolling…. first one looks like roots haven’t hooked up yet, continue to top feed until she hits the res.

Think your water temp might be off… I believe the target is 68….. but don’t engrave that in stone until one of the hydro crew confirms or denies. Yeah that rh is very low for seedling & veg see VPD chart below,… use color key in top right corner for plant stage of growth to keep temp & rh on point, but for now you want to be in green zone….

Weed roots do love air but not exposure to light, IDK maybe try aluminum foil instead of mylar disc. May need to add more pebbles, make sure no light is getting into res… air yes, light no.

What color are roots?
How does reservoir water smell? ….. it’s good that you are using enzymes
How often do you change res?

when mixing your nutes always add cal-Mag first, stir & wait 15 minutes, add the enzymes stir & wait, add the NPK stir & wait, measure ph, adjust ph then feed.

I’m going to ask @Rexer to drop in with his rising falling, static, chart…. and to overwrite any errors I may have made

Welcome aboard, more will jump in soon

 

[MrMiguardi]

Thx for the response bro!
Some nice info i need to save, for example i didn't know about the cal mag order when mixing nute, and that table are very useful!
Yesterday evening the two plant look a little bad than the photo, root are white and clean, one has a little light yellow color un the root tips but i will keep her controlled... but no new root.
Thinking on some lockout nute problem because of the ph fluctuation or the past week or a stress problem i injected some tap water with only a little bit of root stimulator inside of the rockwool cube.
Today seems that the two plant feel better, new leaves are grow a little bit, and the one with the spot on the leaf has 3 new root visible under the pots.
The second one in the photo has officialy entered veg stage, growing a ton of root in only 24h!
This evening i will feed them again with tap water and looking for new root sign.

I was wrongly using Vit-c as Ph down feeding bacteria combined with maybe dirty and old clay pabbles that dropped dust in the water has caused foam and ph fluctuation so i changed the res and sterilized all.
Now using GHE ph down/up ph seems ok.
My plan is to make a sterile system, change water less as possible with maybe the help of some h2o2, the goal is to pratice with an hydroponic system that use less water as possible for a future project.

Res before chage had a strange odour but not smell or rotten stink.

 

[013]

awesome, good yes the cal-Mag drops out of the mix unless you do it right. Indoors it’s not enough to monitor enviro - you must be able to control it, following VPD will get your enviro right.

yes water source, ppm & ph matter greatly in hydro. clay pebbles need to be nuked clean & thoroughly rinsed between uses. So good job on nailing that foam.

Smelly res water is bad. Brown roots / slimey roots are not good, but some nute products do stain roots. We will get a hydro person in here soon

starting a journal will help us keep track of you How to make grow journal

 

[nivek]

4 big buckets i see i think. getting that wee plant from tiny pot to big pot is tricky indeed. for sure a watering and nute issue. if the plants are not watered correctly during this phase then they for sure are not being nuted properly either

they absolutely require nutes at this point,, very minimal but still needed.

i would suggest it is a timing issue,, not enuf this and too much that,, all to do with water. keep nutes at bare minimum and adjust the watering routine. temp should also be minimum 20 i think

i do hempy but this is similar and i see this issue a lot,, for me too, still figuring it out

baby to youngun is the tuf part,, karma sent

 

[MrMiguardi]

Thx to all.

Yes 4 big bucket with big pots, i've watered and sprayed the plant every day until the root touched the water level but maybe i've stopped too early.
Ive got two inkbird sensor that regulate hum and temp automatically so there should be no surprise.

Plant n1 still growing bigger leaves and bigger root, i'm positive about it!
Plant n2 has officialy entered Veg, with nice leaves and nice root.
Plant n3 despite the water injection show no sign of growht, no leaf growing or new root in two days.
Plant n4 didn't sprouted, bad seed i think, so that bucket are void for now. i'm seedling a new seed and trying to grow it side by side with the other 3 older plant.

I've used atami root booster for recovering the two "sad" plant, that contain algae extract and now i'm facing some greenish zone one the rockwool cube immediately cleaned with some h2o2 on a cotton swab, ph stable, i think the system is stabilized.
There's a lot of things to learn about!

I will take a look at that topic, collecting some photo and trying to make a journal in the next days.