Ok, since no one has responded--apparently we don't know the answer! I do know that lemons take 6-9 months to mature. I am unsure about the color however. I would suggest contacting Four Winds Growers. They are based out of California, and have always been super helpful with my citrus questions. When you find out about the color, please repost the answer on here! I have a Eureka lemon tree, and am curious to know if mine are going to be 'green lemons' also!

Jessica

Here is a link that might be useful: Four Winds Growers

Thanks, Jess. I went ahead and contacted my county extension agent, who seems to to think the lemons are ripe. They're about 6 months on the tree now.

jrdibble - The lemons on my Eureka never turned yellow. They were on the tree for 10 months! I finally picked one and used it on a fresh flounder dinner. WOW! It was terrific! I don't know if 6 months on the tree is long enough since they do require between 6 and 9 months, but if you have many of them, try one. They are very juicy even green.

Gosh, how strange....I've read they're the leading market cultivar; how can they not turn yellow? It goes against the laws of the universe! LOL

I guess that's why we're supposed to keep track on how long we've had them on the tree! I think mine will be ripe in Jan/Feb. I only have one lemon right now, so I'll have to think of something special to use it for! (Even if it is green...) :o)

Jessica

I will try to look up the exact temperatures later, but I do believe that the temps need to drop a sustained amount of time for fruit to turn yellow. I know in the tropic climates,
fruit stays green.

Commercially, lemon maturity is determined by size, not color.

The SuperFreak speaks! Whassup! Your point is well taken. But have you ever seen a mature green lemon for sale? I guess I just thought all lemons were yellow. (A bit naive for the young citrus grower!)

I just wrote an article about lemons & limes on my blog. What I tried to let people know is that lemons are actually yellow, and limes are green. Why? Because in my country, Taiwan, all lemons are green! So I have definitely seen lots of green lemons for sale.

I used to think that lemons were green and limes were yellow until the first time I lived in an English speaking country. I finally realized that actually lemons are yellow and limes are green outside Taiwan. And no one believed me when I tried to tell them in Taiwan lemons are green, just like lots of Taiwanese people don't believe me that outside Taiwan lemons are yellow and lime are green. : )

Here is a link that might be useful: ¶§¥ú¬£³ø

We have a three year old Meyer lemon tree which is just now delivering its first crop of lemons. We've tried to be patient, allowing the lemons to go completely yellow, but they seem to be in a holding pattern, staying just a little bit green. Should we wait until they're completely yellow before we pick 'em? Is it important to pick before the first frost?