Why are they rotting and falling off at around 1 inch long? They have about 20 blooms on them at one time?
There are a number of diseases that can cause the squash to rot on the vines.
A bit more investigation and looking for signs that help identify the fungus or bacteria will dictate treatment or how to correct.
The links below will help you.
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-pumpkin-rot-disease.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/tips-for-growing-squash.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-blossoms-falling-off-vine.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/pollinate-squash-by-hand.htm
CAN YOU TRAIN YELLOW CROOK NECK SQUASH TO GROW ON TRELLIS OR FENCE INSTEAD OF RUNNING ON GROUND?
Yes! Make sure your trellis is sturdy!
https://www.gardeningknowhow.com/edible/vegetables/squash/growing-squash-on-trellises.htm
can you grow squash upright either by trellis or fence or etc? wanting to save space in garden also about planting in corn too.
Yes, you can!
This article will help you.
https://www.gardeningknowhow.com/edible/vegetables/squash/growing-squash-on-trellises.htm
I also have zucchini and cucumbers they are growing fine the same soil.
This is blossom end rot. A deficiency of calcium and often magnesium. All of those plants will, eventually, suffer the same symptoms, as they are all susceptible to the condition.
Dolomitic lime will correct the issue rather quickly. The finer the grind, the faster it will work.
This article will offer more information:
Hiya so I recently found out what's wrong with my pineapple plant due to your website, it matches all the details of crookneck. Now your treatment solution is using 1% Zinc Sulfate? So can I buy an average Zinc Sulfate solution off amazon and use that? How much do I use, 1 drop? I don't know what the 1% means either? I'm sorry I'm clueless! Thank you!
If you buy the solution already mixed just follow the directions on the bottle. You can also buy foliar sprays of micronutrients that include zinc, manganese and sometimes iron, which can be used. Follow application instructions.