Adjective (modifier in compound words): early, initial.
Varhais appears in our example as part of the common compound noun, varhaisperuna, which means ”early potatoes.”
Other examples of the use of varhais- as a modifier include varhaiskesä (”early summer”), varhaislapsuus (”early childhood”), or varhaiskypsä (”precocious” [literally ”early maturity”]).
Varhais is a form of the adjective varhainen.
Varhaisperuna are the earliest maturing potatoes, some of them harvested in as little as 7-8 weeks after planting. They should be cooked as soon as possible after digging them up to get the freshest taste. They are popular in Finland.