A strange crop

The allotments are just next door - and passing by I wondered why the owners put plastic bottles on top of their canes?

Does it protect the canes from water? Stop you poking your eye out? Or a form of bird scarer?

Allotments seem very popular around here.

"1.3.2 Profile of allotment holders
Surveys of allotment holders shows the allotment population is aging (Appendix 1).
Whilst the number of females with plots has declined since 2002, the number of female plot holders is still higher than the number of males. In 2007 the number of plot holders with an ethnic background was 4.2%, whilst 9% were disabled. The biggest draw for allotment holders is the production of fresh fruit and vegetables, closely followed by exercise and contact with nature. On average a plot holder spends 11 hours a week on their plot during the summer and four hours during the winter (Allotment Survey 2007)"

(from: Cultivating Communities: A Growing Challenge ? An allotments strategy for the City of Edinburgh (2010-2015)