Modifiers matching lettuce:

• crisp,
• mixed,
• bitter,
• hearty,
• new,
• dark,
• torn,
• leafy,
• fresh,
• mild,
• clean,
• small,

Simple categories matching hearty:

• dish,
• filling,
• seed,
• food,
• soup,
• grain,
• fare,
• seafood,
• ingredient,
• vegetable,
• meat,
• meal,
• sausage,
• green,
• lettuce,
• veg,
• pasta,
• plant,
• sandwich,
• fish,