Pea pods can be empty for a number of reasons, including pest attacks or lack of watering. In this Quick Tips video, Kevin Smith, BBC Gardeners' World Magazine, reveals why this can happen, so you can tackle the root of the problem.
There are a few reasons why pods don't form peas. An invasion of pollen beetles might have damaged the flowers enough to destroy the crop, or the plants could be suffering from mineral deficiency. A very common cause is simply a lack of water. Water the pea plants whenever the soil feels dry, and this should resolve the problem.