Lack of pollination.

Check the FAQ at http://faq.gardenweb.com/faq/organic/

Read both of these articles.

1. Squash/cucumber/melon flower: male vs. female

2. My squash/cukes/melons are not fruiting!

Here is a link that might be useful: the FAQ

If you are hand pollinating and the plant is still aborting the fruit then something else is wrong.

Common causes of fruit abortion on otherwise healthy plants that have been hand pollinated is (1) excessive nitrogen fertilizer - kicks the plant out of production mode and back into growth mode - use a low nitrogen higher phosphorus fertilizer.

Or (2) plant is root bound in the container or suffering root rot if in the ground. Any chance you have have excessive amount of rain recently or may be over-watering?

Dave

Yes Dave, excessive amounts of rain, but good drainage in the pot. I have sandy loom soil with a very high water table and have thought too much water could be the problem in the past. It seems the year I had good yield was in a high spot that required daily watering.

So do squash like a well drained, full sun location?
I'm determined to figure this out this year!
Thanks

I have yellow squash in raised beds within 3 feet of each other. In Box A the plant is small but I have gotten one foot long squash off of it. In Box B the plant is huge and healthy and puts out squash like crazy but they shrivel and die at about 2 inches or so I haven't been able to harvest a single squash-- very frustrating. They have roughly the same soil and receive the same water.

This is 'square foot gardening' so Box A has some okra planted around it - Box B is next to cucumbers and am getting a bunch of cucumbers if that is maybe making an impact.

Im getting ready to just pull the plant out and replace it with something i may actually be able to eat :)