What you need to do is either get a product called citriside from
http://www.growwheatgrass.com/citricide.htm or apply a spritzing of one cup of water with one tablespoon of grapefruit juice added, once every other day or so. Don't soak the
seeds or sproutings just mist them and when the grass starts to grow same thing, just give the whole flat a misting of this when you water it about every other feeding. The citricide is best but can be hard to come by. Check out this website too, it's full of wheatgrass/juicing supplies -
http://877myjuicer.com and they have a cool wheatgrass sprouter
http://www.growwheatgrass.com/citricide.htm that I picked up for under $40.00 and I've had no mold whatsoever. They carry
seeds too and for that matter, some pretty cool juicers -the one I got:
http://877myjuicer.com/product/LEXENHEALTHYJUICER which is totally easy to use and clean. Hope this info helps you! let me know if you have any other problems after you try this out.