Little Plant: now that everyone has had a shot at your problem let me put in my two cents worth. First, I hate to rain on your parade, my friend, but if you've got the six hole two lamp Aerogarden model; that's the one least adaptable for what we want to grow. If it's the, "Space Saver-6, look in your reservoir and I think you'll find that you don't have the same nutrient pump that the Classic and super duper models have. You got the same bubbler set up as the Aerogarden-3 model has and a smaller capacity reservoir then the seven holes models. So you got what you paid for. You should have done your homework first.
JME02100 and Tom 420, obviously have a hard on for the Aerogarden and I'm sorry to see that because I've had nothing but fun with mine. I've got three of the less expensive seven holes models that I've upgraded with the taller hoods equipped with three high intensity CFL's and I've surrounded them with mylar reflectors. They keep my sugar bowl full so I'd have to consider the source there.
I have to agree with Mr. Natural, if your garden is in an ambient temperature of 90 degrees, F., that looks like a problem. The best info I've been given is low 70's at night and mid to high 70's in the day time. I'm guessing you have it in a closet or cupboard where there's no ventilation. Yo might want to fix that. Also you might want to be ware of mold if you have your Aerogarden enclosed in an unfinished wood structure.
Tom 420: has his opinion on the nutes but I don't necessarily agree with him. I tried a couple of different brands, including Aerogarden's new and improved liquid nutes, and I didn't like it in any formulation. For what we're growing I haven't found anything better than Technaflora's "Recipe for Success." But Tom 420 is right, you have to feed your babies. I used to go with pH balanced water for the first week because seeds are supposed to have everything the plant needs for the first week, but now I use the whole Technaflora program with their recipes. I start it on day one with the seedling/ cutting formula, then the vegetative formula, the flowering formula next and finally the pre-harvest formula. And I've had no problems. The sample kit I originally bought for about $30 had everything I needed and it lasted a long time. I'm taking a hydro class and the instructor recommended using 1/2 strength the first two weeks and the last two weeks but after already using Technaflora's nutes the way they want them used the last couple of years I haven't seen the need to change.
Last but not least, part of your problem may be the strain you're growing, the age of the seeds, how they were stored and for how long. If you're hell bent on growing with that model Aerogarden you might want to go to their web site and read everything they have there that maybe you didn't get with your unit. You can also call customer service and ask them for help. Just don't tell them what you're growing.