yellow leaf tips, but too early for nutrient issues.

I'm very new to this. I'm using an ebb and flow types system. My minions are about 2 weeks in. I started them by germinating in a cup of water. Then planted them in the mini rockwool cubes. After the root system started to stick through the bottom, I cut out the center of some bigger rockwool cubes, and popped those babies in.

2 of them are doing great. The other 3 have started to curl their leaves, and the tips are yellowish.

Now, since its only two weeks in, I dont see why it would be a nutrient issue. I'm actually not adding anything yet, except keeping an eye on the pH.

To help, here is what I think may possibly be the issues:
1. I didnt pre-soak the bigger rockwool cubes. From what im reading, since they are pH nuetral, maybe when the 5.6 pH water was soaked up, it mixed a bit higher then intended.

2. I waited for the first two to have roots sticking through, but the other 3 didnt. I figured it would soak it up and everything will be fine(i double check by feeling it). The two that had the roots popping out of the bottom of the mini rockwool cube plus one other are the ones showing the yellow tips.

circulation:
I have a fan in there to give them just enough wind to wiggle a little(to strengthen up the stems).

light:
I'm using a 400watt sodium bulb. But it is actually up pretty high, since its a fairly strong light for the little guys. They are on an 18/6 cycle.

quality:
I have an air purifier running (it doesnt oxygenate or anything, its just gets the dust and shit out of the air).

Am I right in thinking that its too early for there to be nutrient issues? Any ideas what the cause could be? or how I can further diagnose this? or am I just being overly worried?

doeas the the purifier make Ozone, if so it will harm the plants search ozone damage on here. alos are you leting then get dry enough befor watering are the roots browning the soggy rockwool will get stagnet and hurt the plants.

Thanks for the response!

withoutAchance said:

doeas the the purifier make Ozone, if so it will harm the plants search ozone damage on here.

Click to expand...

Its a Vornado AQS500. From their website:

The passive electrostatic filter system is charged by the force of air rushing through it, there are no electrode discharges to create ozone emissions.

Click to expand...

The sodium light gets kind of warm. But I keep the house pretty cool to compensate.

withoutAchance said:

also are you leting then get dry enough befor watering are the roots browning the soggy rockwool will get stagnet and hurt the plants.

Click to expand...

I cant see the roots from the bottom of the bigger rockwool cubes(they havent busted through yet). But when I put them in 2 days ago, they were white and moist.

I run the system two or three times a day, mainly because what I have been reading says its impossible to over-water them. So, no, I've never let them get dry(should I?).

I squeezed the rockwool a bit (not enough to put pressure on the roots), but to get enough water out of it to test. The water that came out had a pH of 6.5. So I lightly squeezed it a bit more to get as much water as I could out of it. I then filled a cup with the water from the reservoir (5.9), and poured it on top of it.

This is the third of fourth time i've run the system. If the pH of the water soaked in the rockwool was this high, I suppose its possible that the pH was originally higher than 6.5. Basically what i'm thinking is since i've been flooding it with water at ~5.8, it must have originally been higher.

To some of you experienced guys, does this sound plausible? or am I grasping at straws? If so, any suggestions?

I picked up some flownova, and have my ppm at ~500, and pH at ~5.9. I gave the rock wool another little squeeze to try and get it to soak up some of the good water. I'm hoping after tonights night cycle everything starts to pick up again. It seems growth is stunted, and the leaves on 2 of them are curling further downward.

Are you allowing your tap water to rest for 24 hours from the tap? It contains chloramines that need to off gas or they will bind with the fertilizers or just hurt the plant.

Snow Crash said:

Are you allowing your tap water to rest for 24 hours from the tap? It contains chloramines that need to off gas or they will bind with the fertilizers or just hurt the plant.

Click to expand...

Yes and no. I put the water in the ebb and flow system. But I haven't changed it yet in the past few days. So, when i originally put the water in, no, it didnt sit. But now that it has been in there for a few days, yes, technically it has sat.

needs to sit 24hrs min with no fert in it

They look like they are doing a ton better today. I added those nutrients yesterday, and lowered the pH a little extra to compensate for the rockwool's high pH. The leaves are still a bit yellow, but it looks like its fading, and it looks like they are uncurled, but not completely straight yet.

I will take some pics in a bit and post them.

Thanks for the help guys!

withoutAchance said:

needs to sit 24hrs min with no fert in it

Click to expand...

I think the way I will do this, is give them a real good watering, and then change it immediately after. That way I can push them 24 hours without having to run the system again. Otherwise, im not really sure where I can store 25 gallons for 24 hrs.

adding the pics I promised.



The pics dont really do them much justice. They look better today. I've started using the grow journal if anyone is interested in following any further.

you don't have to wait the whole 24 hours.. boil the water let it sit for 4 hours and your good to go.

fyi, I added nutrients and the issues went away. I guess it was time.