abundant (esp. AmE), bountiful, bumper, good, large, rich
We've had a bumper harvest of apples this year.
She returned from the conference with a rich harvest of knowledge. (figurative)

bad, disastrous, poor
a series of poor harvests in the 1830s

cereal, corn, grain, potato, wheat, etc.
final

bring in, gather, gather in, get in, reap
They were busy getting the harvest in.
We are now reaping the harvest of our hard work last year. (figurative)

fail
The strawberry harvest failed because of the drought.

season (esp. AmE), time
festival

after (the) harvest
Potatoes are normally sprayed after harvest.

during harvest, during the harvest
Potatoes often sustain damage during harvest.
During the harvest they work from dawn to dusk.

harvest of
a good harvest of potatoes

Harvest is used with these nouns as the object:
barley, coconut, corn, crop, grape, hay, oats, organ, rice, timber, wheat