Amber, check with your local ag agent, or one of the well respected citrus tree growers/nurseries in your area, Maybe not the person you bought the trees from, as their knowledge sounds a little wanting. New citrus don't need a lot of fertilizer the first year, but after that year, you should start fertilizing in the early spring (after any chance of frosty temps have passed), then 4 applications during your growing season, which would be roughly February through Sept/early Oct. The spots - not sure, can't really see them up closely enough. Doesn't look like an insect. Looks more fungal in nature to me, which I find odd since you're in such a dry area of the country. The damage to the leaves in the first photo could be from snails, earwigs or other leaf-eating bugs. I try not to treat (except for snails, which I use an iron phosphate snail bait versus a metaldehyde snail bait, as metaldehyde is very poisonous to dogs, and dogs are attracted to it. No so for iron phosphate snail bait.) You can also use Sluggo Plus, which is iron phosphate and spinosad, which will kill sails, slugs and earwigs. Patty S. Here is a link that might be useful: UC IPM - Managing Pests in the Garden: Citrus

There is a good chance that the fruit will not be true from seed. If that is so you may end up with a different variety of fruit and a thorny tree. I remember my mom telling me this when I wanted to plant a tree from fruit I got as a kid.(My mom was big into fruit trees and an amazing gardener.) I found this on GW: As for will they be worth anything - citrus started from seed go through a long period of juvenility. When the plants are juvenile, they usually have huge thorns (maybe 1" long on average), and will not flower or produce fruit for several years. Just how many years varies for the plant. It can be as few as 2-5 for key limes, up to 7 - 15 years for grapefruit. Also, not all varieties come true from seed (as in, the fruit you eventually get may not look or taste like the parent fruit). Lemons though, do usually come true from seed if I remember correctly. So, if you just want the satisfaction of growing a pretty (but thorny) evergreen plant from seed - you're on the right track. If you'd like a lemon tree that flowers now, and produces lemons maybe this year, or next year - consider buying a grafted tree. These trees are propagated from mature citrus and that fools them into thinking they are "old". So, you get flowers and fruit much sooner.

Those are on the top horizontal surface of the tree, and I also see dry tan patches. To me that looks like classic sun scorch. Leaves can be sun burned, especially at those temperatures, and it's the leaves that get the most direct sun that will burn. There comes a point at high temperatures in full sun that the leaves lose water faster to the air than the roots can pull up from the soil, and then you get that scorch. It's not fatal, especially if you get it out of the sun during the heat wave. It may lose those particular leaves later, but will grow new ones to replace them when the weather is less hot. No need to fertilize any more than normal, don't remove any soil either. And don't repot it during hot weather either. Just make sure it's watered well, and get it out of the sun during the hottest part of the day. If I were you, I'd put it in an area that gets shade at the hottest part of the day until the weather cools down to the mid-90's or less. Then it can go back into full sun. Or you can put a patio umbrella over it during those hours.

I'd say Silica is correct about the ratio of light to soil temperature. This is only meant to simplify the balance of the relationship between leaves and roots. Leaves use light to start the process of making food. The leaves will tell the roots that it needs all the ingredients of the photosynthesis "recipe" to finish making food. So in normal ideal outdoor conditions, the roots provide and send up water+nutrients needed to complete the food being made in the leaves. Imagine that to citrus roots 55F and lower is considered to be like frostbite to the roots. The roots cannot do anything when the soil is cooler than 55F. It cannot absorb water, it cannot function at all and so it basically sleeps to conserve its energy. However if the leaves are having a blast above the soil and getting a sunny Hawaii vacation thanks to strong indoor lighting, it will try to make food. The leaves cannot stop itself from reacting to light. When light hits the leaves and warms the leaves enough for it to function, the leaves will react to light no matter what and must start photosynthesis. But if the roots are too cold, it cannot send up the missing ingredients because it will be in hibernation. Eventually the leaves will lose moisture since it is in active mode. While the leaves are active and losing moisture, the roots are inactive and cannot send water up to hydrate the active leaves. Like running a marathon without any sustenance. The tree will sacrifice it's own leaves if it cannot provide itself the water or nutrients that is needed to continue with the process. Sorry if my post was long. I feel that it can be simple to understand if I try to compare it to thing we already understand. So to answer your question Mike, when the tree is getting plenty of sunlight that means leaf activity goes up and therefore root activity must also go up in order to keep the balance in their relationship. In order to make the root function as much as the leaves, temperatures of the soil surrounding the roots must increase. If root temperatures (and therefore root activity) cannot be increased because heating is too expensive, then the activity levels of both root and leaves must be in balance. Either the root or leaves will have to follow the other. If root activity cannot go up to parallel the leaves then inevitably is it up to the leaves to follow the roots footsteps and also be very inactive. That means reducing light levels to reduce leaf activity for the sake of matching the cold/inactive roots. I think of the leaves and roots as two parts of one living creature. It cannot live without one or their other. Both parts must follow each other because they are two halves of a whole. One is the pie crust and the other the pie filling. You cannot have a pie with a very thick crust but 2 teaspoons of filling and vice versa! It just wouldn't make any sense. You would have a very disfigured and unappetizing pie! They must both contribute the same amount to create a balanced and delicious food! I can get creative when I need to when it comes to explaining things so if this still wasn't easy to understand at all, feel free to let me know. I hope this helped anyone confused about the whole roots and leaves matter