In this paper, we present Krishi Kontho (literally, "agricultural voices"), which is an agricultural information service that utilises pre-recorded voice messages, and SMS, that are pushed to smallholder farmers mobile phones at intervals carefully choreographed with the life cycles of their crops. We present the design of the service, and we present the result of an eleven-month field trial in rural Bangladesh. Findings indicate that this type of service, that synchronises messages with cultivation practice, may improve crop yields while reducing the use of agricultural inputs such as fertiliser and pesticides. We find that the farmers in the field trial deemed the service to be of value to them in regard to improving their agricultural practices. We conclude by discussing our findings and their implications for the design of agricultural information services, including the challenge of designing for specific temporalities, or rhythms of practice, in rural Bangladesh and elsewhere.