Cucumbers grown in the wrong conditions can become bitter or tasteless. Plant them alongside sunflowers. As they grow, the cucumber tendrils will use the heavy sunflower stalks for climbing support and you'll have the sweetest cucumbers you've ever eaten.
Companion Planting With Vegetables and Flowers - Organic Gardening
Helpful flower and vegetable combinations! Marigolds help tomatoes and roses grow better. Nasturtiums keep bugs away from squash and broccoli. Petunias protect beans from beetles and oregano chases them away from cucumbers. Geraniums keep Japanese beetles
Gardening Companion Planting> & improves the growth and flavor of tomatoes and repels flies and mosquitoes. Lovely purple cones top the plants if you let them go to seed. & will thrive near carrots, cucumbers and onions.