Canterbury farmers are starting to get uneasy about rising agri-chemical and fertiliser prices.
The Foundation for Arable Research told growers last month there were increasing concerns about the agri-chemical supply chain.
Farmers are being advised to do a stocktake in their sheds and talk to suppliers.
Federated Farmers Arable chairman Colin Hurst said agri-chemical supplies were tight, and the main concern was with fodder crops.
"A lot of the fodder crops - kale, swedes and fodder beet - are established and have had most of the chemicals applied, but there will still be follow-up spraying as well as fertiliser at the moment and going forward."