Answer: The color of the fruit rind is not always an indication of ripeness. Rinds turn color (green to yellow for grapefruit and lemons, and green to orange for oranges) when there is sufficient cold weather. If weather is not cold enough, or plants are indoors, the rinds may not turn, but the fruit is still edible. The most reliable method is the taste test. You can also squeeze the fruit with your hand: if it is really hard, it probably needs to stay on the tree longer. The longer fruit stays on the tree, the sweeter it becomes. Citrus will not ripen/sweeten further once it is picked. Most lemon varieties have a long bearing period and can be harvested between August and February.
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