Honesty is the best policy. "Our plans for this school year require more funds than we raised at the fall fundraiser. At the next PTO meeting, we will discuss ways to scale down our plans or what additional fundraiser we can plan to make up the difference. We hope to see you all there!"
Have found out the hard way that sometimes the parents don't see value in the same things that we spend time to fund, so give them an option. Then, if no new people show up, make plans to go ahead with the second fundraiser and also figure out what you can cut from your budget. I'm sorry that you are in this position.
I'll be frank, our main fall fundraiser didn't go very well at all. (Yes, we've been in school since 8/4.) And we *need* to do another to accomplish what we really want to do this year. We have one picked out and only lack one approval. I just need ideas on how to word it to parents who, like all of us, don't want to be nickled and dimed all year. Thanks!