Mystery problem

[VGro]

Ladies, Gentlemen,
is there anybody out there who can tell me what in heavens name I'm doing wrong? All measureable parameters are according to the book - I think.
PLEASE help me out before I go nuts .



How long has this problem been going on?
Eversince I got started, first on earth, then coco and now hydro... Frustration is the name of the game.
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents)
SilverBox 90 x 90 x 180cm

What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...)
Wilma "4" tank with aeration pump and circulation pump which start 15' before feeding and run for 30' / electronically controlled "Neo" water heater
What STRAIN are you growing?
Skywalker (+ sweet tooth in previous attempt on coco)
What was the establishing technique? (Were the seed or clone?)
Seed
What is the age of your plants?
About six weeks since germination start
How long have they been in there mixture they are in now?(coco,soiless etc..)
Always Grodan mineral wool
How tall are the plants?
10 to 15 cm
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in?
Vegetative from the looks of it, I reduced light time to 12h about twoo weeks ago.
What Technique are you using?
What substrate/medium are you using?(Hydroton, RockWool etc.)
Grodan mineral wool
What is the Water temperature?
20°C
What color are your roots? White? Brown? Are your roots slimy?
Can't see that
What Nutrient's are you using?(If growing soiless)
Canna Aqua Vega
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
45ml Vega A + 45ml Vega B + 40ml Rhizotonic + 50ml Cannazym on a total of 20L of H2O
How often are you feeding? (If using soiless)
03h00 to 03h10 / 08h15 to 08h25 / 12h15 to 12h25 / 15h15 to 15h30 / 18h15 to 18h30 / 21h15 to 21h30
If flowering, when did you switch over to using Bloom nutrients?
Not yet, still waiting for signs
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
As stated above, then Ph- as last - a couple hours after nutrient addition
What is the EC you are using?
EC 1.6 (rises up to 1.8 after a few days, then I correct back down with fresh water)
What is the pH of the "Tank"?
Setpoint 5.6 to 5.8, rises up to 6.3 after a few days, then I correct.
Are you sure your calibration is correct on your equiptment?
Yes (Tec-Hu Ph meter - Hanna EC both calibrated ± 4 weeks ago)
What is your water temps?
20°C
When was your last feeding change? (ie. grow-bloom-micro-additional)
About tree to four weeks ago when I changed from seedling mix to veg mix.
How often do you clean your system: example: Flush out water replace with clean water and nutrients?
Nutrient solution replacement every two weeks
What size bulb are you using?
LED-it-GRO 90W LED from 10h00 to 13h00 / 250W Philips Master Son-T-Pia + Diamond reflector + "BAL" electronic ballast from 12h30 to 22h00
What is the distance to the canopy?
± 40-50cm at a 30° angle (from vert) for the LED / ± 45cm for the HPS
What is your RH Factor(Relative Humidity)?
between 40% and 50% with HPS on, 60% to 70% during night time and LED operation
What is the canopy temperature?
17° to 18°C at night, 22° to 26°C during lighting
What is the current Air Flow? (cfm etc.)
Ø 100mm tube fan at ± 70 to 80% fan controller setpoint (with thermostat swithching to max. rev. at ± 29°C, which doesn't happen)
Tell us about your ventilation, intake exhaust and when its running and not running ?
Ø 300mm swing fan (rev set on 1 of 3) + Ion generator from 10h00 to 22h00 / tube fan from 09h00 to 09h30 and from 12h30 to 22h00
Is the fan blowing directly at plants?
Yes for the swing fan, distance to canopy ± 80cm - plants swaying gently
Is your water HARD or SOFT?
Hard, start Ph of up to 8 and a bit
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Tap water that's been sitting in a buffer for a couple of days, buffer has a circulation pump and aeration pump, operatin four times a days for 15'.
Are you using water from a water softener?
Nope
Has plant been recently pruned, cloned off of or pinched
Nope
Have any pest chemicals been used? If so, What and When?
Nope
Are plant's infected with pest's
I sure hope not!

 

[Snype]

You're attachment didn't work and you have no pics or an explanation of your problem that I can find. Your pH is getting a little high too so you might want to start pHing every day. I have the same problem with my Blue Cheese and have big pH swings. Set your pH for 5.2 and let it rise to 6.0 then pH again and that should get you through 3 days or so. When things go bad in hydro they happen a lot faster than soil. If you see any burning on the tips of your fan leaves, then you're feeding them too much nutes and go lower. Hope this helps you. If your problem is big then flush with pH'd water for a few days and you don't want your res temperature over 70 degrees F so your heating might be a bad idea. You want your temps in the 60-69 degree F range.

 

[Snype]

If those pictures were taken within the past couple of days then you are over watering them like crazy. They are very small for 6 week plants and if you can't see the roots at the bottom of the cubes then you'll know I know what I'm talking about. When you first start out from seed, you have to let the cubes dry out about 30-40 percent or so, so the root has to find the moisture and grow to find it. Plants that small don't need that many nutes. Let them cubes dry out for at least 24 hours then just give them plain water ph'd to 5.6 for the next 7 days and your nutrient level that you're currently using needs to be cut to a quarter strength after your flush for at least 2 weeks.

EDIT: I see the cubes they are in now so I know why you won't be able to see the roots. But if you do what I say here you'll be fine and on your way!

 

[o.sparkles]

If you have been having this problem in every medium you probably have something infecting them environmentally. Do you have ANY gnats or fliers and have you looked at the roots for bugs or damage with a magnifier?

 

[VGro]

All right! Finally someone who comes up with a decent explanation for this, I'll get on it right away - and keep you updated about the results off course. O.sparkles, I"ve been having VERY close looks at the little b*stards, without noticing anything suspicious as far as diseases or similar go. I did spray the whole thing (read: the equipment) with a (low concentration) bleach solution before even getting started. No - it does not SMELL bleach anymore... )) Just to have a clear conscience, I'll inspect thoroughly again tomorrow.

Bye guys, and thanks again.

 

[Kcar]

Cut out those first two waterings atleast. The lights aren't even on, are they?
Very much looks like over watering to me.

 

[Leonard NeemOil]

Did you condition the rockwool before use?

Rockwool is basic (alkaline) by nature, soak it for at least an hour in a pH solution of 5.0-5.5. Rockwool will melt at pH levels below 5.0.

3) For all other Grodan products- SOAK, FLUSH, then PLANT!
Soak in plain water (pH 5.5) for 1/2 an hour (longer if soaking granulate).

from grodan site
http://www.hydroponics101.com/sw62665.php

 

[Leonard NeemOil]

And this from Grodan site

* Do not over water. When the stonewool feels almost 1/2 way dry, it is time to completely fertigate with some drainage from the block or slab.
* How much to water depends on the environment and growth stage of your plant.
* Download our brochure Watering and pH for further information.

http://www.hydroponics101.com/sw62698.php

 

[VGro]

Hi Kcar,
thanks for the reply. My lamps run alternately (1/3LED - 2/3HPS) with a half hour overlap at the changeover. See also the schedule above.
Mister NeemOil,
yes I did soak my plugs though I just might have omitted the flushing part a little. For the main bulk of the medium I did flush the whole thing through with Ph corrected water and a little nutrients.

Anyway, I guess over watering probably is the culprit since I stopped pumping solution over my medium THREE days ago and the bottom part of my medium (I can just slip my hand between the side of the pot and the medium) is still more than moist. My little buggers are showing no signs whatsoever of drying out-in fact I feel they're improving slightly... I'm planning to wait them out and only water when I see the first signs of "droopiness".

Ciao,

 

[Snype]

Don't wait for them to droop before you water. Just hand weigh your medium until they feel about 30-40% dry, then water. You want to add more stress to your plants?