Lemons are ready to pick as soon as they are yellow or yellow-green in appearance and firm. The fruit will be 2 to 3 inches (5-7.5 cm.) in size. It's better to wait until they are the right size and not worry so much about the color than to wait for them to be completely yellow.

How long before a lemon turns yellow?

They gradually mature and gain sweetness; in fact, the fruit may take as long as nine months to ripen. Once the fruit is mature, it can be left on the tree for a few weeks, but it does not ripen more. So first off, the lemons may not be turning yellow because they have not been ripening on the tree long enough.

Are lemons yellow when ripe?

Color. A greenish hue to your lemons might leave you wondering, "Is my lemon ripe?" The answer is that if you have Meyer lemons and they are more yellow with a tinge of green, or an egg-yolk color, they're either ready for harvest and will result in ripe lemons.