seedling peddler; nurseryman
A person who sells young plants or seedlings, often in a market or nursery context. The term is straightforward and not particularly common in modern daily conversation, but it is understandable.
In spring, many seedling peddlers appear at the market.
As a nurseryman, he sells tomato and eggplant seedlings.
Compound of 苗 (seedling) + 売り (selling) + 人 (person). The derivation is transparent from its components.