Newbie indoor grow--leaves rolling inward and tips yellow?? HELP!!!!

Hello everyone. So as the title says I have a bagseed of an unknown strain which I had decided to put in a pot and try to grow. It is using a soil which is a decent potting soil that I found at walmart and am watering with rainwater which I have collected. It is inside of a stealth cabinet that I have built (have in another post of mine) and is under 6 26watt cfl 6500k. Im not sure why the leaves have been curling from the sides of the leaves inward (hotdog style) and the tips are getting slightly brownish yellow. Any help or comments would be greatly appreciated.

Ill try to post pics asap

How many days since sprout?
Temp and Relative Humidity?
Did the problem begin in the lower nodes or those closest to your lights?

Sounds like heat/light stress how close do you have your lights to the plant?
Try moving the light and mist the plant to cool it .

The temp was getting a little hot inside the box (around 89 degrees) so I am now keeping one of the doors open until I can manage to install a fan to pull the hot air from the cabinet. Not really sure what the humidity is for this grow??? The sprout is only about a week old. I will try to mist the plant and keep it cool and see what happens.

whoa rain water. Is it ph'd my rain will be 8.0 sometimes. Fill a bucket with tap water and let it sit in thesun for a day to rid it of chlorine. Or buy a brita water bottle filter and filter a gallon or so then ph it to 6.5ish. Thats your problem is nutrient lockout of some sorts. I used rain water on an indoor setup and it nearly killed every fan leafe leaving just the bud sites. You really should have been more prepared. Read a few books now and keep us posted through this thread id like to see how you do

Actually it probably is heat stress but you will run into nutrient lockout if that rainwater isnt ph'd not sayin rain water is bad but it has to be at least 6.5 to achive good results. Theres tons of minerals in it and without the right acidity it will just get blocked out and either runoff of sit inthe soil then when you water witb ph'd water boom insane nute burn from the unknow build up.

Just be cautious if you want to see this through. Your lights are good for now but when you flower you should have some bulkier CFLs if thats your route. Use some 42w 2600k. Just pick one up every week or so and then when ready to flower replace or even add to the 26w. The 42s run alot cooler for there light output and have more lumens.

I want everyone to grow killer buds. Sub par weed is not worth all the work. Cfls can achieve dankness but only if done right.

Thanks newbie9 for all your advice. I will have to check the ph of my rain water I am using. I have moved the plant away from the lights and the door has been open all morn. Hopefully the leaves will see some improvement. Bout to put some pics on shortly