I've read that bitter flavor comes from stress during the plant's growth. This might be extremes in temperature, or too little moisture, for example. I hope ours aren't bitter- I know cucumbers need a lot of water.

Hmmm... my cucumber flowers are large and the petals are splayed outwards, making it easier to pollinate cucumbers than the huge zucchini flowers whose heavy petals get in my way. I wonder if you have a different variety of cucumber than I do.

I actually looked up "calicum" to make sure that wasn't a supplement I'd never heard of before, but it seems you mean calcium, and you are right about egg shells. What I have read is that if you dry your egg shells, you can then blend them into a fine powder and add this to your soil. Now whether calcium, lime or similar measures are what your plants need, I don't know, but the egg shell remedy is pretty easy to make and to sprinkle onto the dirt.

I found this link, which may help you: http://www.informeddemocracy.com/pumpkin/growing.html

It's much cheaper to build your own wooden beds (or even to buy the wood and nails and pay someone to drill the boxes together). However, if you are hell bent on buying them, you can find them at some local gardening centers. We saw a kit for $125 or more- outrageous! It cost us $60 to build one bed, but it was a lot of labor, so I can understand wanting to buy them. That being said, when I build beds in the future, I will use concrete blocks, bricks, or some other material that I don't have to drill together!