Question

how would know that the onion crops are ready to be taken out colour ​

Answer 1

Answer:

Bulb onions are ready for lifting when the leaf tops begin to yellow and die back.

Answer 2

Answer:

Onions are ready to harvest when the bulbs are large and the green tops begin to yellow and fall over. Stop watering the onion when around 10 percent of the tops begin to fall over.