Yes it is.
Plural: Heads of lettuce
Singular: Head of lettuce
8 for tomatoes and 4 lettuce heads
0.95
8-10 heads of lettuce depending on how much lettuce you use
One head of lettuce should feed 8-10 people, so for 50 people factor 5-6 heads of lettuce.
The correct spelling is "lettuce" (the leafy salad green).
a billion
28 = (70 / 5) * 2
Lettuce can come in bunches of leaf lettuce or heads of lettuce.
The number of lettuce heads needed for 40 burgers depends on how much lettuce you plan to use per burger. Typically, one head of lettuce can yield about 10 to 12 burger-sized leaves. Therefore, for 40 burgers, you would need around 4 to 5 heads of lettuce to ensure you have enough for each burger.
13 pounds
That is about 8 heads
The noun lettuce has varied usage in the plural. Traditionally the usage is "three heads of lettuce", but the alternative "three lettuces" has become very common during the last century. The collective noun is always "I like lettuce" or "this farmer grows lettuce".