This is the first of a set of notebooks recording Bateson and Punnett's experiments with sweet peas and the first of three notebooks for 1903 crosses. The sweet peas recorded here were sown at the farm between March and April 1903.

The general format of the record is that the parents are recorded as numbers with a superscript or sometimes as a named variety. Since sweet peas can be selfed, many crosses have only a single parent. The date of sowing and the date of planting out are recorded, together with the location on the farm (row number) and other observations on the plants such as colour.

The plants on [pp 85v-86r and 95v-96r] are marked ‘important’. At the back of the notebook there are maps of the plots where the plants were set out [pp 106v-111r]. [Page 109r] also includes drawings of chickens from Bateson and Punnett’s experiments in poultry breeding [see poultry notebook series MS Add.10161/1/1].