Hey buddy, the problem with your plants could be a number of things.. Marijuana plants need a set level for everything, water, light, temp, humidity, soil ph, nutrients.. All these factors can affect plant growth. Ok, when starting your seeds, it is best to germinate them between 2 wet paper towels. Keep these in a dark warm moist place for 24-48 hours and you should see a tap root growing out of the seed. Let the tap root grow until it reaches a length of 1-2". Next, you need to plant your seedling in some soil, not a big pot just yet, just a small pot (8" at the most). Now when you plant it, dig a small hole 1-2" deep and drop it in. Now cover with a fine layer of soil. water the soil until it is supersaturated (you can use a weak solution of rooting fertilizer, or if your soil comes prefertilized, then it is not neccessary). you will see it sprouting within 2 days, keep it warm and never let the soil dry out completely, yet make sure never to overwater. The best way to do this is to have drainage holes at the bottom of the pot.
Now when the seedling sprouts, do not fertilize(or use a very weak solution), and make sure the soil never dries out completely, yet keep it fairly moist. it should reach a height of 2-3" within the next 2 days. Make sure you have sufficient light, (about 3000-7000 lumens/SQ FT. Using "daylight" or "cool white" CFL's work best (5000-6500K). Make sure the temp never goes over 30 degrees C, try to keep the temp between 21-28 degrees. Use a fan if the room is too hot . Blowing a stream of air on the seedling will help promote strong root and stem growth.
After a week, you should have at least the first bladed leaves, and now is the time to use a fertilizer(weak solution as it is still just a seedling) with a higher phosphorus and pottasium content for strong root and stem growth. Make sure never to be the "cautious grower" and tend too much to the plants, this can cause problems such as overwatering, and overfertilizing. Let the marijuana run it's course, and only concentrate on keeping the soil from drying out completely, keeping the temp below 30 degrees celcius, and never let the lights touch the plants.
Now if you follow these instructions, you should never have problems with your plants(well major ones anyway). Let the marijuana run it's course, and never be too cautious. Good luck and happy growing
