2 week old plants looking under the weather

[Addicted]

I have these plants in a rdwc hydro setup,20 gallon capacity 4 site.At first I thought it was low humidity I've been trying to keep it up but have been having trouble with it.It started with the lower leaf edges curling up, but now has progressed to the lower leaves looking like they are starting to yellow with brown spots starting to appear on them.

Ph has been on the lower side at about 5.6 5.8 waiting for it to drift up but hasn't.
Temps are a steady 75.
400 watt mh.
Gh micro and bloom nutes/lucas. 660 ppm with 334 of that being a half dose of calmag
Using ro water.
Humidity 30% struggling to keep it even that high.

Any ideas what's going on?

 

[Headbudz77]

Just for start I would remove that tinfoil from the pots, they easily create hot spots and have bad reflection rate.
Maybe that is all that is happening, could those spots be water drop marks from watering?

 

[Addicted]

I took the foil off tonight, it was just to keep the heat off the black net pot lids.ill see what happens. The brown spots look like tiny spots of dead plant material. Here's a pic of the setup.

 

[Addicted]

Here's a better pics of spots

 

[Headbudz77]

My experience in DWC in none. But really looks like nute burn from spill. But since you don't top feed...I doubt it.
You will have to wait for a DWC grower to help you there, as I would say Cal/mag def also creates spots...


A 4 strain grow. Second try.

https://r.tapatalk.com/shareLink?sh...-strain-grow.-Second-try..57614/&share_type=t

 

[Heavily Medicated]

First off, I too have never run RDWC. That said, those plants look hungry. 600 ppm should be right in the ball park, but I think you should have more of your ppms being the GH nutes, and less of the CaMg. You never mentioned res temps, do you monitor it? The spots I would not worry at all about unless they start to spread or get larger. Sometimes any little thing unknowingly gets splashed or spilled and can create tiny little dead spots. No more than what you have now would not be a concern, but worth monitoring. I'll tag @Waira for you, he I'm sure will be able to join in with some awesome knowlege.

 

[Addicted]

Res temps are 65.

 

[Addicted]

I might do a water change and start over with 1/4 strengths nutes and full strength calmag.Now it looks like a tip is burning.This is only my second time growing,the forst time I had to sto before completion due to unforeseen circumstances.

If I do a water change what strength nutes and should I do, and should I do a full dose of calmag?..I think they look a little worse today.

 

[Addicted]

Getting some water made up for a water change,decided to try 1/2 strength nutes and full calmag.I gotta try something they are looking worse.

If anyone has any advice id love to hear before I do this.

 

[Heavily Medicated]

At two weeks I would shoot for 1/4 or 3/8 strength nutes and 1-2 ml/L CaMg. You are really too early to be having any kind of CaMg problem and at only two weeks old the full 1/2 strength nutes will be too much. I start out feeding from day one at 1/8 strength, week 2 I up to 2/8 (1/4) strength, week 3 up to 3/8 strength, week 4 up to 1/2 strength and stay at 1/2. Sometimes this is a little hot, so watch your plant and adjust accordingly. I grow flood to waste in soilless medium.