Horticulturists have several things to do. Unlike farmers who depend on agriculture for their living these horticulturists do not depend for their living hood on a farm or garden. Of course they can also depend. For example, there can be a variety of professions for horticulturists. But all these boil down to things related to horticulture only. There are engineers for crop production, managers of business of fruits, vegetables etc. There can be researchers, plant breeders, genetic engineers and crop specialists.
As horticulture involves growing gardens or garden plants, the horticulturists instead of growing single crop in larger fields do grow different crops in a single field. This makes them differ from farmers. The horticultural communities grow gardens with a variety of crops which also include fruits. Often certain trees which are useful in general can be observed in their gardens. They retain these from the nature and grow in their gardens.
The produce plants in small unlike agricultural community who produce in large scales. Horticulturists grow plants from seedlings or cut plants to grow them into matured plants. They later transfer these plants to markets for selling or send them to ornamental gardens.