Knocking Hoe is a 7.7-hectare (19-acre) National Nature Reserve and biological Site of Special Scientific Interest near Pegsdon in Bedfordshire.

[4] The site is a flat-bottomed valley with steep sides.

The unimproved chalk grassland has several nationally rare plants, including moon carrot, spotted catsear, field fleawort, burnt tip orchid and pasque flower.

There are also a variety of wild flowers such as the autumn lady’s tresses, which has been studied on the site for over fifty years.

The ancient strip lynchet field system is of archaeological interest.