I thought I was being clever when I decided to grow cucumbers and herbs in the same pots. BAD IDEA!!!! For starters, my pots were to small to accommodate both a herb and cucumber plant. (To add insult to injury, I threw in a few zinnia seeds!) In addition the watering needs varied between the herbs and the cucumbers. I struggled to keep the basil/cucumber combo well watered. However, the oregano/cucumber combo was to wet for this herb. But more important, I never checked to see if herbs and cucumbers make for good companion planting (plants grown near each other to attract beneficial insects, deter pest, and provide support, shade, nutrients etc.). They do not! Cucumbers do not do well with herbs that have a strong aroma!
A pot that is about 12"-16" inches deep or about 24" in diameter can can grow 2-3 cucumber plants. . (5 gallon buckets also work well and hold 3 plants.) Cucumbers have deep roots and need a steady or constant amount of water.
Herbs on the other hand have either shallow (oregano) , medium (parsley) or deep or long roots (basil). A 14" diameter pot works well for most herbs. Basil and parsley needs lots of water, where as oregano doesn't.
Cucumbers rely on insects/bees for pollination. A cucumber flower remains open for one day and pollination must take place in that day. It takes about 9 visits per a single flower to adequately pollinate/transfer pollen. Low yields and misshapen cucumbers are often the result of poor pollination.