It could be BER or with squash it could just be insufficient pollination - common in the early part of the season and they tend to look the same except for the size of the fruit. Either way the plant will grow out of it and produce once whatever is stressing it settles. There is a great FAQ on causes of BER over on the tomato forum you may want to review.

If you wish, you can try doing some hand pollination (also a FAQ on how to do it) - that usually breaks the cycle. Meanwhile remove all the bad ones, avoid overwatering, no more feeding now, and hope the weather cooperates to remove the stress on the plant and it will settle down. Plenty of season is left for squash. ;)

Dave

Squash can be affected by BER. It is caused by not enough calcium making it into the developing fruit. Could be not enough calcium in the soil (you would need a soil test to confirm), but anytime water doesn't get into the plant fast enough there will be a lack of calcium as well.

You said you don't water much. If the soil is too dry (or conversely too wet in a heavy soil like clay) then the plant may not be getting enough water. Excessive nitrogen can also cause problems with calcium uptake.

BER is one of those frustrating problems because it's root cause (lack of calcium) is known, but there are many factors that can lead to the plant not getting enough calcium and you pretty much have to consider each one and eliminate it as the cause.

Thank you both for the info..

You are welcome for the information, but I did want to post again to say Dave's (digdirt's) explaining it could be due to lack of pollination is right on.

If you are experiencing BER then refer to my post, but since it is early in the season and lack of pollination is often a problem at this time it could well be that. It's really deceptive too. You can have what appears to be a large fruit growing and then one day it just starts to decay/rot.

I have grown Atlantic Giant pumpkins and found them to grow to basketball size only to abort due to lack of pollination. What I am trying to say is the female flower will grow a fruit only to abort it due to lack of pollination, but for awhile it really looks like a viable fruit and can grow quite large.

Will calcium nitrate help? I usually side dress with it on my tomatoes, squash and peppers . I'm certainly no expert, but I usually do better with squash than my neighbors wish I did (I started putting in a couple of recipes with the bag of veggies on the doorstep!!).

I'm glad you reposted justaguy because yor third paragraph explaining the female flower growing a fruit and then aborting it due to lack of pollination helps me understand it better.I have blooms and lots of little and larger squash and all have a rotted end.I'm going to remove all the bad ones as they appear and hope for the best.Debbie

Depending on your part of the country and what your soil is lacking, dolomite lime, gypsum and bone meal all have accessible calcium. I suspect that bone meal may be the quickest to work, but I'm not sure about that.

For the fastest results, spraying a weak solution of calcium chloride solution on the leaves several times should help. You should be able to google for specific instructions.

Sue

Ah but a different thought

Excessive nitrogen depresses the uptake of calcium

If the pod changed color and started to grow, it's BER, If it did not change color and died, it's lack of pollenation

A very slight difference

Any veggie that the seeds are inside the part that you eat is subject to BER

Hand pollinate the female flowers. Pick a male flower (one without the little squash) and remove the petals. Then use the center of the male flower like a brush to *paint* (pollinate) the female flowers.

Zeuspaul

Squash can be very sensitive to both problems. BER is esp. frustrating because it can be caused by too much or too little water. Too little can be an easy fix.

The good news is the plant will still make enuff fruit that everyone will still hate you & squash.

Good Luck,
Gumby_CT