Leaves turning upwards and some spots, help!

Hi everyone, this is my first grow and after a few initial problems I thought everything was going well. However a few days ago the leaves started to curl and face upwards also their are some spots developing on the leaves.

I have attached some pictures for you to look at. In the first picture you can see how the leaves are curling and starting to face upwards. The next 2 pictures show the leaf damage. The spots marked "2" is old damaged caused by water droplets on the leaves and direct sunlight. This happened about a week ago when they were young. The spots marked "1" are what i'm worried about at the moment. They look brown in the picture but they look white under the lights, also the leaves seem to be yellowing and some of the tips look white under the light.



I know the stems are quite long this is because they were not put under the lamps straight away, they were just on the windowsill for the first week.

I have searched round the forums and I think the cause of the problem is heat stress but i'm not sure (could the spots be spider mites?). Any advice on this problem or my setup in general would be much appreciated.

About my setup:
The seeds germinated about 2 and a half weeks ago and were potted in small plastic cups. The plants were re-potted about a week ago into larger pots using a moist seed and cutting compost (Levington brand). Since re-potting they have been given roughly 10ml of water every couple of days or so. The plants are kept inside an upside down perspex fish tank with holes drilled in the top and an air gap around the bottom. I have used 2x 20w fluorescent energy saving bulbs to light them (picture below). The tank is covered with a reflector made of white paper (picture below). They were on a 24/0 light cycle which I changed yesterday to an 18/6. The room the plants are kept in is heated with an electric heater. The temperature and humidity inside the tank range from 26-30C (19-86F) and 49-65% humidity. I am not currently using any fans or means of air circulation other than removing the lid periodically.

what's your PH? What are you feeding them? How much?

I haven't tested the PH of the soil I will do that tomorrow and report back.

I have not been giving them any nutrients yet, they only have the nutriants in the potting compost. The back of the pack says it contains N P K (but no quantities), trace elements, wter retaining agent and that it is a high phostphate formula for strong root development.

Should i be using nutes now?

Your soil doesn't look like its cut with anything... Are you using Miracle Grow?

No its a brand called levington. Here's a link -> http://www.lovethegarden.com/products/composts/levseedcutting.html

I'm using deionised water to water them could that be causing a nutrient deficiency because of the low ppm of the water?

I tested my ph today using a soil test kit. It's kinda hard to tell from the shitty colour chart but i think it was about 5.5.

The tips are still looking white but the leaves have strightend out a bit. I thought the spots might be some sort of nutrient deficency so i bought a bottle of Plagron Terra Grow today. The bottle said to mix 5ml into 1l of water (1:200 mix) so i put about 2ml in a liter and gave each of the plants about 40ml of the mixture.

I also bought a 600w hps today with a Sunmaster dual spectrum bulb. The plants are about 2 and a half weeks old from seed. They are looking well other than the spots on the leaves. Is it ok to put them under the light now?

My guess, those plants got burned by the pre-ferted soil. If they seem to be recovering though, just leave them alone and follow a wet/ dry soil watering cycle for the next week or so. I'd skip the soluble fertilizer also, until they let you know when they need some more feed. You will know because the bottom leaves will yellow very slightly, as opposed to the burning you saw the last two weeks.

Mite damage tends to look like little salt specks running in a uniform pattern across your leaf tops. You can also flip the leaf over and see the little buggers with the naked eye.

Personally, I'd leave those plants under fluoros for a while longer. I'm sure they'd also like a fan and some air movement in that space. Air circulation works magic, plants need a steady source of fresh air.

And 10 ml of water isn't much. Wait for the container to dry completely, then water the container thoroughly until you see some runoff. In a beer cup of soil with no perlite, this means you're watering with probably a half cup or a little more than that when the soil mix is fully dry.

Hope this helps. I suggest you do some reading in the soil forums.