asked Her Majesty's Government:

What duties landowners have to inform neighbours as to what chemicals those landowners are spraying on their land.[HL7282]

In general, there is no legal requirement for landowners to tell neighbours about most chemical use on land owned by the landowner themselves. There are two notable exceptions:

when farmers and growers use sulphuric acid as a desiccant; and

aerial spraying.

The landowner must tell their neighbours 24 hours before they begin their treatment with sulphuric acid and they must put up signs and notices about treatment.

For aerial spraying, the operator must tell people living within 25 metres of the boundary of the land to be treated, and the person in charge of any hospital, school or other institution with boundaries lying within 150 metres of the flight path, 24 hours before the treatment. Again, signs and notices have to be used.

It is incumbent upon the user to make sure that all chemicals being applied are targeted at the land, crop, structure, material or area being treated.

The latest code of practice for using plant protection products—a statutory code giving advice and guidance to all professional users—states that it is good practice to advise people who live or work around the area to be treated of the intention to apply chemicals, giving them information about the chemicals being used. It also explains that it is good management to consider extra measures such as leaving an untreated area next to the neighbouring property, putting up signs letting people know the pesticide being used and where they can get further information, and giving out information cards (if available) to those who want them.