Leafy crops
Leafy greens can be practical because you may harvest usable leaves without waiting for a large fruit. Their needs vary by season and climate, so choose varieties suited to your conditions.
Climbing crops
Some beans, peas, cucumbers and other vining crops can use a trellis. Growing upward can free ground space, but the support must be sturdy enough for the mature plant.
Herbs and compact varieties
Frequently used herbs can provide value from a small footprint. Compact vegetable varieties can also be worth considering when standard plants would crowd the available area.