In my home garden, my cucumber plant leaves are turning brown/ yellow. It...
The foliage of the cucumber looks like it may have been subject to a type of environmental stress. It does not look like an insect or disease problem. Some possibilities may be a leaf scorch or a type of air pollution damage. We have been getting some reports of this. No control is necessary. See the link on air pollution effect on vegetables http://extension.umd.edu/learn/air-pollution-effects-vegetables
Monitor your plants and if you notice additional symptoms you can send photos.