Hi --- I've grown all kinds of varieties and colors of okra in my original EBs but I don't know the size of yours? No troubel planting six useing two cups of 10-10-10 ferti;izer mixed into a good quality container mix not top soil. An EB is about 30" long so 10" apart should be the spaceing.
Did you know that Okra is considered "nematode candy" ? Got that information from a master gardening seminar. In our sandy soil there must be gazillions in a square foot !. Apparently they are attracted to the okra roots. When you have okra you can still pick the veggies, but when you pull up the plant you fill find the swollen and gnarly roots (a sure sign of nematodes). Solar heating the soil only works a few inches down and those microscopic blighters can be a foot or more down in the "soil". Incidentally, they're not happy in rich, amended soil. So amend, amend, amend !