Growing cucumbers on a trellis makes them easier to harvest. However, cucumber plants require the most pruning attention when growing on trellises. Although they can be trained to grow up the trellis, they are not true vines and will not do this themselves. According to the University of Florida Cooperative Extension, umbrella trellising is the most popular pruning system that produces high cucumber yields.
Prune all of the lateral branches that the main stem produces until the tip of the main stem grows over the topmost wire of the trellis.
Prune the main stem once it grows over the topmost wire of the trellis. Wait until it produces one or two leaves at its tip, which is the growing tip.
Prune the first four to six lateral branches that grow near the base of the plant. Allow all others to grow freely as they will.
Prune all shoots on the top two lateral branches that grow upward so that nothing sprouts above the top of the trellis. Allow all of the shoots that grow down toward the ground to grow freely.
Prune the growing tips of the lateral branches when they reach the ground or grow beyond the trellis.
Prune all fruit that grows on the bottom 30 inches of the main stem of the cucumber fruit. Cut the stem 1/4 inch above the top of the cucumber. This selective fruit pruning will redirect the cucumber's energy to produce more vegetative growth and more fruit throughout the growing season.
Prune any vines or stem that appear to be diseased, insect eaten or otherwise compromised.
When pruning lateral branches, do not leave stubs. Make the pruning cut as close to flush with the main stem as possible. Wipe your pruning shears down with rubbing alcohol before using them. Then wipe after each pruning cut to reduce the likelihood of the spread of disease. Discard or compost all pruned material. Leaving the litter at the base of the plant encourages the development of disease and fungal infection. Prune when the weather is warm and dry. If pruning cuts are made during cloudy or damp weather, the likelihood of infestation increases. Cucumber plants not trained for trellis growth do not need to be pruned as aggressively. Simply remove any broken, diseased or compromised leaves or stems as you see them.