Size

• Tomatoes and cucumbers need a container that is at least 12 inches wide, although wider containers work fine and allow you to grow more plants. Choose a container that is as deep as it is wide. For example, look for a 12-inch wide pot that's 12 inches deep. Go up to large bushel planters or half whiskey barrels, or choose several smaller containers.
  
  

Reasons

• Cucumbers and tomatoes set deep roots, in contrast to shallow-rooted plants like lettuce. When grown in the ground, depth is not a problem; if the plants don't have enough room to set roots, their growth will be reduced and your crop will suffer.
  
  

Type

• Cherry tomatoes work well for hanging or ground containers, but they're not the only kind of tomato you can use. Most kinds of tomato grows well in containers, but cucumbers are pickier. Look for cucumber plants or seeds that are marked as good for containers, like varieties Spacemaster or Pot Luck. These grow less deep and bushy than in-ground cucumbers without the downgrade in cuke quality.
  
  

Spacing

• Overcrowding your containers will leave too little space in the pot for roots. Even deep containers only have so much room for plant roots. Grow one cucumber plant per pot, up to 1-gallon pot size; 5-gallon pots could support more plants. Follow the spacing recommendations on your tomato plants; the many varieties have different spacing needs.