I have grown about a dozen basil plants from seed and the plants seemed to be doing well until recently they started drooping over. The stems don't seem to be strong enough. Can anyone tell me what I've done wrong or what I can do to fix?

Thanks

How much light have the seedlings been grown in? This is the most important factor in producing strong stemmed compact plants. I also spray my seedlings with a strong solution of Chamomile Tea for Damping Off. Increase the available light and if the seedlings are spaced close together try spacing to provide more light. A weak fertilizer solution of say Miracle Gro will help. Either spray the seedlings or water in carefully.