Too soon for nutrient deficiencies?

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Drip
T5
Distilled water @ 5.8
69-72 F
40-42 RH
18/6 cycle
Watered 3x daily @ 10 min. increments.

These 2 are in the 9th day of light. T5 sits 3-5 inches from top of plants. I've noticed they have slowed in growth and developed leaf discoloration. From what I've researched it looks like a P deficiency. Is it too soon to have nutrient deficiencies...?

Before I forget - what about the roots? This setup is strictly vegetative, when the time comes they'll go into a flower room. The roots are starting to poke through the bottom of the rockwool...:wtf:Whats a good method to keep them in the dark without adding hydroton or anything that will stick to the roots?

Thanks!
-Colour

[dejayou30]

Whats that brown stuff surrounding the plant in the hole in the rockwool? You shouldn't be feeding any nutes, only water at this point. They look stretched, might want to move the light closer.

[colour]

They're in Rapid Rooters. I too thought they looked stretched but was more concerned about the leaf color. Right on, moving the light a little closer may not be a bad idea.

--They haven't been given any nutes. Is it better to add CalMag when nutrients begin or do it now?

[Weedhound]

I'm wondering about ph of your rockwool....they look like your ph is off. They're all twisted and odd colors.

Something is off for sure but it doesn't seem like a nute def.

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I soaked rockwool in distilled water @ 5.8 for 24 hrs then rinsed them with 5.8 distilled prior to putting them in...Im going to check PH right now...

[colour]

Well, my PH was, in fact, off. I calibrated then tested and it was at 6.5. Will PH jump around from day to day?

[Weedhound]

I haven't used rockwool myself but I've HEARD of it's ph issues. Next time I'd probably soak the rockwool (and keep checking the ph) until it stabilizes at the ph I want. May take longer than 24 hours.......I know it does when prepping hydroton.

At this point, just keep checking and changing it back which you may have to do several times a day for now. The issue will improve when you get some nutes in there with their ph buffers.....and the problem WILL go away eventually as the medium stabilizes.

[colour]

Thanks Weedhound...its been a few hours, I'll check it again.

Before I forget - what about the roots? This setup is strictly vegetative, when the time comes they'll go into a flower room. The roots are starting to poke through the bottom of the rockwool...Whats a good method to keep them in the dark without adding hydroton or anything that will stick to the roots?

Anyone have suggestions on this one?

[Weedhound]

Well what exactly is your veg setup? Ebb and flow, drip or ?

[colour]

Drip. I didn't think of this until I noticed the roots peaking through.
What about putting visqueen plastic around the rockwool and poke holes on the bottom for the water to drain...? That make sense?

-Colour:hippy:

[gainesvillegreen]

What about putting visqueen plastic around the rockwool and poke holes on the bottom for the water to drain...? That make sense?

-Colour:hippy:

I would avoid doing that. The best thing that rockwool's got goin' for itself is the ability to retain water and plenty of air for oxygen. If you plastic the cubes, they will not drain properly and your setup will fester.

I would also drop the light directly on top.

Take the remaining with a grain of salt:

I used to use rockwool for germination and rooting cuttings. When doing either, I never checked the pH. I found that since the seedling is supplying it's own nutrients, and the cutting can't absorb any, the pH did not matter since pH of a media is most important for nutrient uptake. If your main media is rockwool, if you're going to have your mature plants eating nutrients from rockwool alone, pH is very important and is best tested on a sample from the block itself.

For seedlings, I have also always used a 1/4 strength nutrient solution when watering.

[colour]

Thanks Gainesville!

Do you think the color of the leaves is because of a pH problem? What would cause the leaves to start to fold up like a damn taco?

-Colour

[colour]

Taco leaves? Why?

[Weedhound]

Fold up?

[colour]

Ahhh exactly, fold up.

[Weedhound]

Well abnormal ph can cause a strange curling of the leaves......but so can too much nitrogen or something along that line as well. Got any photos?

[colour]

Im pretty confident the problem is pH. They're 12 days under light and barely have their second set. Only pH'ed water for them right now...

[colour]

photos are at top of post ^^

[Weedhound]

ph or your rockwool is staying too wet....i'm afraid I'm not really familiar with rockwool but have heard it tends to retain moisture.