These fruits and veg­eta­bles are typ­i­cal­ly in sea­son in March in Wash­ing­ton state:

• Apples, Brae­burn
• Apples, Cameo
• Apples, Fuji
• Apples, Gala
• Apples, Gold­en Delicious
• Apples, Granny Smith
• Apples, Pink Lady
  
• Apples, Red Delicious
• Beets, Red
  
• Bur­dock
• Cau­li­flower
• Cel­ery Root (Cele­ri­ac)
  
• Leeks
  
• Mush­rooms
  
• Onions, Red
• Onions, White
• Parsnips
• Pears, Asian
• Pears, D’An­jou
• Pota­toes, Fingerling
  
• Pota­toes, Red
• Pota­toes, Yukon Gold
• Shal­lots
• Sun­chokes
• Sweet Pota­toes (Yams)

See What’s in sea­son in Wash­ing­ton state for sources and a Google Sheets spread­sheet with data for the whole year.