Potatoes: Compete for nutrients and attract pests.
Sage: Releases chemicals that stunt cucumber growth.
Melons: Increase the risk of fungal infections due to similar pests.
Tomatoes: Both are heavy feeders and can deplete soil nutrients.
Brassicas: Cabbage, broccoli, and others attract harmful insects.
Herbs: Mint and oregano can overtake cucumber space.
Sunflowers: Their large roots compete for water and space.