Also, you need some air movement. When growing indoors, we are trying to duplicate Mother Nature as much as possible. If you take a look at the plants and trees outdoors, you'll notice that they are in constant movement. That's because of the air moving across them. With your little babies, the GENTLE air from a small fan will strengthen the stems by stressing them a little ... kind of like weight lifting.
For the moment, go to the store and buy some of those cheap, plastic picnic forks. Put them in your medium with the handle down into the soil. Now, place the stem of the plant between the tines of the fork, being very careful not to break the stem. These plastic forks make great little props for the babies.
Vi