Many plants are selected for their natural red foliage, and many plants simply turn red. I won't talk about autumn leaves, because I know that's not what you're asking. At low light levels, green leaves are most efficient at photosynthesis, but on sunny days, there is little or no difference between a green leaf's and a red leaf's ability to trap the sun's energy (carry on photosynthesis). Many pigments play some part in protecting various plants from sun's rays, but red anthocyanin is most effective at protecting plants from exposure to intense energy by absorbing ultraviolet light. As light levels intensify in some plants, the levels of anthocyanin increases. This can be especially noticeable when sugars build up during periods of heavy photosynthesis while the growth rate is reduced (why bedding plants often turn purple in the chill of spring temps). Often in young plants or in new growth, where chlorophyll and cuticular wax production (also protects from damaging light) has not yet begun and which would be unprotected from UV light, anthocyanin production increases. Parts or even the whole plant are colored by "juvenile anthocyanins," and thereby protected from damage. As soon as chlorophyll production begins, the production of the anthocyanin pigment is reduced. The presence of noticeable amounts or a build-up of anthocyanin in plants is specific to the plant type, but can also depend in part on the soil conditions, light levels, temperature, pH and a few other cultural influences I'm sure I left out. Al

It looks pretty good. @ poncirusguy, OP is in northern CA, no citrus greening here yet. Yeffi, you say you "recently fertilized, added azamite, epsom salts, and iron/zinc", does that mean you added a complete fertilizer, AND added azamite, epsom salts and iron/zinc, or are you saying the added azamite, epsom salts and iron/zinc IS the fertilizer you added? I ask because, the only problem I see is the new leaves are a bit all-over lighter green, which can be a symptom of Nitrogen deficiency. Young leaves are often lighter green than the mature leaves, but if they don't green up by the time they are full sized leaves then it may be a nitrogen deficiency. The products you listed are all micro-nutrients and minerals; they don't contain any nitrogen, so they wouldn't help your problem. I'm not a fan of epsom salts(Magnesium sulfate) anyway as both magnesium and sulfur are included in most good Citrus Fertilizers, and a complete fertilizer has the micros and macro nutrients in balance so one does not adversely affect another. I think the horse manure had the nitrogen your citrus needed at first, but it does get used up and so after about 6-8 weeks the nitrogen was gone. Plus with that much watering you will need to feed more often. If your soil drains well enough, and as the tree looks healthy, it probably does, that amount of water in the heat of summer is fine, but you do need to feed more often when you water more often. I would get a good complete citrus fertilizer, (not fertilizer stakes though) and use it according to the label. Ideally you should be fertilizing at least every 8 to 10 weeks or even more if the label recommends to. Overall though, except for being a little nitrogen hungry, it's looking very nice!

Hi I have a Ruby Red in a pot. I got it for my dd because she adores grapefruit. It is very sweet. No need to add sugar even. It fruits really well for being potted. In Phx we had a large mature Oro Blanco grapefruit in the ground that put out way more fruit than we could ever use lol. As with all citrus, environment, watering schedule, fertilizer, pests etc can all play a role in fruit development. It sounds like you have inherited a nice tree. I think you should fertilize the tree. Make sure you are also giving it deep watering a few times a week and water before you fertilize. Mature citrus are usually fertilized 3 times a year. If you fertilize Valentines Day, Labor Day, and Memorial Day are a good way to remember lol. Also, one other thing to check for is: Look at your graft line. It should be down towards the bottom of the tree. Make sure there is no new thorny growth underneath that graft line. If there is prune it off. Sometimes these suckers from the rootstock will take over and make the original tree less vigorous and can sometimes affect fruit quality. Here is a good link for info on citrus culture Here is a link that might be useful: Citrus Culture

Thanks again for the info Betsy. This one had just a small spot - some of them have thick instances of what you see in the picture. But it very well might be too much water from our clay soil not draining well during some of our rains. It does hold a lot of water at times. I have been trying to condition the soil to help this problem. The season did start out pretty wet. The varieties that I am growing are generally not this soft and do not have this stuff in it - so it has worried me. It has made the texture very disturbing when eating. They are getting kind of soft before they are getting all the way ripe too, so I have been letting them get the rest of the way red before cutting them. By that time, they are really soft. So maybe by that time, they are actually over ripe. That makes me feel better if it might have been from too much water. That means some of my later ones might not be as bad. Thanks again, Mike