Unless the nasty customers are well armed, retail nursery work is quite safe. It is rather physical at times, and involves moving heavy objects, but is quite manageable. Although plenty of pesticides are for sale, not many are actually used, since the turnover of most plants is too dynamic for many diseases or pests to get established. Just don’t go ingesting any of those pesticides and you should be fine. You may not be able to break away to go get lunch, but there has to be a better option.