阅读短文,填入所缺单词,首字母已给

阅读短文,填入所缺单词,首字母已给
Farmers grow lettuce in the early spring or late summer.Lettuce seeds are half an inch deep.A lot of sunlight and watering (1)h____ lettuce grow.
There are five kinds of lettus:crisphead,romaine,leaf,butterhead and stem.Leaf lettuce can be green or red.Bibb is a kind of butterhead lettuce.Many stem lettuce are in China.Chinese farmers like growing stem lettuce.Leaf lettuce is the easiest type to grow.
Lettuce is very good for (2)h____.Lettuce is the second most popular vegetabie in the U.S.behind potatoes.