Please Help with Diagnosis!

Hello,

I'm 2 weeks into my first indoors grow and so far things are going decent. But just in the last few days I've started to notice an upward curling in the leaves. They're also yellowing from the tips (also new growth), and show rusty spots on the old first leaves. And overall light green color. After reading guides to spot deficiencies, I believe they need Nitrogen or Magnesium, but I think more Nitrogen than Magnesium.

I'm using the Bio-Tabs starter kit (http://biotabs.eu/product/biotabs-starterkit/) which uses fertilizer tabs, 2 of which I placed in each pot. I believe the plants haven't yet fully accessed all these nutrients. I don't want to over-fertilize them, but should I add some Nitrogen now?

Most likely there was alos some heat stress involved, as the light was to close in the beginning, but now that's fixed. I haven't measured pH because Bio-Tabs says there's no need to do so if you use the starter kit.

Pics:

Equipment:
400w hps
Distance from tops? 2 feet
Reflector type? wing
What are the bulb wattages, kelvin ratings, and schedule?
Is there a consistent fresh air supply? yes
Do you have an exhaust fan and a circulation fan? yes
Size of pots? 3 gallon
What medium if applicable. Soil (seedling soil, light, without nutrition)


Growroom:
S) What size of closet, room or hut? Tent, 1.2 x 1.2m
T) What are the temps and humidity levels while lights are on? Average 28 degrees Celsius, average humidity is 45%
U) Have you seen signs of insects in the growroom? no


Your strain:
W) What strain are you growing? India dom
X) From seeds or clones? seeds
Y) Is this an autoflower strain? No

Thank you very much for help!

those are going to shrivel up and die, its what happens, let it be, more will come. It looks fine to me.

In your photos, I see that you aren't evenly watering the plant, for starters. Now, if you water the container thoroughly you'll be giving it too much because those plants aren't quite ready for this size of a container. So in the future, start with a smaller container. Secondly, and probably even more important, your soil seems void of perlite, (the white Styrofoam looking stuff), which helps regulate air/moisture in your soil.

If they live, which they should, don't give any more nutrient, since those tabs probably have more than enough and any more will likely just fry the plant. There's more to it in the long run, but start with this advice and keep movin'.

Thanks a lot for the quick replies!

I see there's already quite a number of mistakes I made: transplanting them too early, not using perlite, and using seedling soil (although that's what Bio Tabs recommends for use with their tabs). It seems well the problem stems from the air/moisture situation in the soil, but at this point the root system is already too large to transplant again to another soil mix. That's just what it is for this grow.

Something else just came to my mind; early on on the grow I sprayed water on the plants and some droplets remained on the leaves. Could they maybe have burned in (under the too close 400w) the rusty spots?

Anyway, after talking to another grower, for the moment all I'll do is to add just a drop of nitrogen to see how they react to it. Also, experimenting carefully with some foliage feeding with epsom salt seems like an interesting thing to do. Maybe just to try on one plant...

Your only on the second set. Plenty of time to rinse the roots off and get the proper mix going. As stressed out as they are I think they would welcome the new perilite mixed in 1:1 with what you have there which hopefully isn't peat moss. Take a 5 gallon bucket fill with tepid water and dunk roots till most of your initial mix has been taken away. Re hit them with that special stuff that is in the kit similar to Mycos. I'd rather see you do that then sit back and tough it out. I just read a journal on those tabs and a guy pulled 2 gpw of some fire with that setup you have there.

Time to start veg nutes, Once the seedling is up and growing it needs food.
1/2 strength first then full.