Seedling trouble - 1st grow

Hi all. Been lurking for a week or so while my seeds split in a paper towel. Out of 6 planted, so far I have 2 sprouts, and 8 more in the towel.

Here's my setup:

closet, lined with aluminum foil, plastic dropcloth on the bottom to protect the floor. 4foot shoplight fluoro, with 2 cool white bulbs. the plants are living (for now!) in a soil/perlite mix inside jiffy-pots (they were on sale and it was a spur of the moment thing). been watering with tap water that i let stand for 24 hours.

Everything goes great with the sprouts until they get about 1" tall. Then they fall over and the stem turns yellow.

My questions are:
1) is it the temperature? kinda cool in there, maybe 60 or 65 degrees? I don't want to put in a space heater b/c of the fire hazard (its a very cluttered closet), and i figured the temp wouldnt be an issue for the seedlings - by the time they flower it will be summertime and the upstairs of my house will be hot as balls.

2) is it the jiffy pots? What's wrong with them, exactly?

3) Is it the light? I read that seedlings can be kept under 24hr lights, and I haven't bought a timer yet, so I've just been leaving the light on. Am I frying these little guys?

Will try to post pictures later. Any help would be appreciated.

Don't use tap water. I'm on my first growth and I was told not to.

i have a filter on the tap, and I let the water stand for 24 hours. we use tap water for all sorts of non-herbal plants and they are fine with it. violets, orchids, the like.

seems to me like youve got everything exept the temo sorted... get a thermometer in there and if its under 60 then thats def why they aint growing if its 65 thats why theyre growin slow, u want 70 to 80

so is there a good way to get the temp up without putting in a space heater? its not cold in the house...

i use tap water all the time...i fill a 5 gallon bucket and leave it out . in 24 hours the floride and chlorine evaporates and its no longer hard water. i guess hard water is the term for tap water thats no good to grow with. you need to check the ph of your water. i thought giving them poland spring water would be good when i started and i figured out the ph was way off and the plant couldnt take in the nutrients it needed to grow. so just leave your water out over night. also i use jiffy pots and they are awsome. i have a 100% sucess rate using them. they come with dirt tablets that when you add water it expands. thats all you need for seeds. and the dirt they give you is great too. i just upsize the jiffy pot to the bigger jiffy pot when roots pop through the bottom, and when i see roots in the bottom of the bigger pot i put them in 2 gallon bags. it works awsome. heres some pics. and also seedlings do not need nutrients, all they can handle is plain old water.
heres the steps in pictures

oh also you need to to a fan blowing on your plant or plants so it wil strengthen up the stem . otherwise they fall over and never get back up. even the weight of water will knock em over but after being in the light they bounce right back up

i also use a space heater in my closets. i have to or it would be too cold.

OK. getting my hands on a space heater tomorrow, and putting a fan in there tonight.

another problem: on each seedling, one of the cotelydons is yellowing. like it's dying. what does this mean?

tried taking a picture but my cameraphone is too blurry.

thats just the little rounded leaf right? if so then dont worry for one moment. those only help push open the seeds. then the true leaves come

don't have much of a choice but to wait and see! turned the lights off tonight so I could get some sleep while still letting warm air from my room go into the closet. I've got a couple more seeds just starting to crack, so even if these ladies go south I will continue my attempts. but i've gotten kind of attached to the first one - I'm naming them with Greek letters, in sequence based on when they sprouted.

Alpha, as the first to sprout, has been subjected to all of my screwups. Pretty sure I overwatered her in the beginning, knocked her over when I did water her... if I see true leaves on this plant I will be ecstatic.

Beta just came up two days ago, and her cotyledons are like stuck together. Again, one of them is yellow.

I put an antique thermometer/barometer combo in there. It shows 72 F. That's not horrible, right?

This whole thing is just really nerve wracking. Also I'm very impatient. Also I haven't smoked in like a month - cause I'm out of POT! go figure.

I know this sounds bad but I left my seedlings outside in 40ish weather when it rained all week and it was pretty fucking cold. I thought they were dead but they were dying i guess and i brought them inside and kept them under alot of light. They seem to be doing alot better now

damn thats some trouble wish i could help but i just planted as well and im very impatient..my advice to you would be to get a glass bowl and smoke the shit out of it and then when you run out scrape the resin

so i left them in the dark with a fan on 'low' all night and they look EXACTLY THE SAME. going to school, putting them back under light - gave them each a shot glass of water b/c the fan dried the jiffy pots right out.

I've got another sprout coming in a different pot, but I dont want to put it in this environment if this is whats stunting my first two. Any suggestions?

good news! beta is showing some true leaves, and I have another sprout from my planted seeds. I am pretty sure alpha is gonna die, though. Thanks all for your help

Update, if anyone cares...

switched to plastic party cups, and put the space heater in there. so far I have 4 seedlings with true leaves and 3 more that have broken the surface. This is out of 15 that I planted originally. I think the others froze before I put the space heater in.

Going to tie these pretty babies down to maximize yield, then flower with fluoros (i'm a cheap mofo and its my first grow). eventually i intend to clone the females into a stealth box - here is my plan. i would appreciate any advice y'all have