Grape shanking

Grape vines grown under glass can suffer from shanking, which means that individual berries within a bunch do not colour up properly, and eventually shrivel up. The affected grapes are inedible.

Save to My scrapbook
Grape shanking causes berries to eventually shrivel up. Image: ©
Grape shanking causes berries to eventually shrivel up. Image: ©

Quick facts

Common name: Grape shanking
Plants affected: Grape vines grown indoors
Main causes: Cultural
Timing: Late summer


Shanking occurs when within a bunch of grapes, individual berries fail to develop their colour. Black grapes remain red and white grapes remain translucent. Affected grapes persist on the bunch, becoming wrinkled and eventually resemble raisins. The flavour of these grapes is unpleasantly sour and watery.



This problem generally results from a variety of growing problems. These include:

  • A poor root system, usually due to waterlogging
  • Soil compaction
  • Poor nutrition
  • Overcropping
  • Excessive pruning when in leaf
  • Pest and diseases
  • Spring chilling in unheated greenhouses


Some simple measures can help prevent shanking:

  • Avoid cropping young vines in the first two years after planting, and allow only three or four bunches in the third year
  • Do not exceed more than one bunch per branch on established vines
  • Pinch out new shoots regularly during the growing season, following the relevant pruning and training methods
  • Cut out the affected berries
  • Ensure that the vine has adequate but not excessive watering or feeding to its root area
  • Give a foliar spray feed as an instant boost
  • Ensure there is adequate drainage

Pay attention also to good grape vine nutrition and care.

Image: © GWI/Dave Bevan. Available in high resolution at

Join the RHS

Become an RHS Member today and save 25% on your first year

Join now

Gardeners' calendar

Find out what to do this month with our gardeners' calendar

Advice from the RHS

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.