The bad part of that branch looks like it has probably walled itself off and the rest of the plant should be okay. It has some healthy looking growth on there. The southern exposure is probably okay in Phx this time of year but come later spring/summer I would put it in afternoon shade or dappled shade. We had ours under a huge cottonwood tree when we lived in Phx where they got dappled shade and they did good that way. You might also consider putting them in the ground and mulching around the root area once you find a spot that your brugs like in the yard in the spring. It is easier to keep them watered and the roots cooler if you put them in the ground and mulch them. Just keep your mulch a little ways off of the trunk to prevent any rot around the trunk. You can run a soaker hose under the mulch and water at night or early morning to prevent evaporation since it is so dry there. At least you do not have to worry too much about fungal diseases or slugs there as some places :) ~Lenette

Key Limes would be one of the quickest to bear fruits from seeds. There are others trifoliate types which can also bear much fruits even earlier than key limes but they are used as rootstocks or ornamentals but not for palatable fruit use. Fortunella hybrids that include hybrids of kumquats such as Calamondins, limequats, lemonquats, mandarinquats, sunquats would often come true to type from seeds and they also bear fruit early. Perhaps the longest to bear fruit from seeds are the pummelos and their hybrids like the grapefruits. The oranges come intermediate when it comes to bearing fruits from seeds. Grafted or not, but very often, the first few fruits from your citrus tree would be lousy tasting and of poor quality. It usually improves with tree age, with the quality starting to peak and stabilize after about three to four seasons from first fruiting. So don't chop off your tree when the first fruits do not compare with the ones you buy from the stores. The vigorous sour orange most probably came from rootstocks used way back in 1872. Here's short history: Before 1880's, most of California Citrus groves were composed of seedling trees. Most popular are lemons and oranges planted in the missions and haciendas of Southern California. Around 1872, the almost seedless Washington navels became so popular that there were not enough seeds to plant more navel trees, and so rootstocks became a necessity. First rootstock used was sweet orange (C. sinensis) and used until the 1940's. The next more popular rootstock starting around 1890's was the sour orange (C. aurantium) which tolerated phyhtopthora gummoosis and produced high-quality fruit. Then the rough lemon (C. jambhiri) was introduced around 1900's as rootstock for lemons and grapefruits where it achieved high yields even in sandy desert areas, but alas, due to poor fruit quality and susceptibility to cold limited its use. Then Cleopatra mandarin (C. reticulata) was used when trying to find tristeza-tolerant rootstocks. Its value was discovered in saline soils. It produced excellent quality grapefruits, but alas, it is susceptible to foot rot and also lost its popularity. All the above rootstocks were popularly used in commercial citrus industry of California until the 1940's. Around the 1940's a big event happened in California. Tristeza virus was discovered to be causing devastation of most citrus groves on sour orange rootstocks. This has lead to various works on rootstock development and changed the rootstock usage in California todate. Thus it ended the use of sour oranges and the hybrids of Sweet x Trifoliate oranges (Troyer and Carrizo) were introduced. Lately, there is a resurgence Citrus Tristeza Virus in Southern California which could mean that citruses on sour orange rootstocks and the sour oranges themselves would face another bout of devastation. As to the ultimate multi-grafted citrus, I currently have a 61-n-1 citrus tree. Tomorrow, I'm grafting 4 more cultivars unto it. Here's the tree when it was still 50-n-1: Fruits from 50-n-1 citrus tree And here's the best technique to add a cultivar when your tree is already mature. Budding is good for younger trees, but bark grafting have better success rates when multi-grafting to a mature tree. Citrus Bark Grafting Demo Here is a link that might be useful: Citrus Rootstock History

Thanks everyone for all the advice. I think you might be right and not fertilizing could be the problem. Next time, I'll do an experiment as Ignatz suggested: one half with no added food, the other half fed. I'll also use a plain seed starting medium. As for why it's 75 degrees, I am growing inside my house (bathroom to be exact) for lack of anywhere better. Our house has poor insulation so the heat runs nonstop in the winter, causing the temp to get kind of high at times. The bathroom is also probably quite humid given people using the shower several times a day, bumping the temp up further. I'm amazed you all think overwatering was the issue. I know how easy it is to do that, and was really stingy with water. Yes, my pots did have drainage holes. They were plastic nursery pots, not peat. Would you say that watering once a week is too much between 1-2 months old? Also: Do you think my city water might be affecting the plants badly? One source said it was high in chlorine, which seems real bad for young plants but perhaps I'm mistaken. I'll try changing up my starting pots, too. Cells to 3.5 inch pots makes sense. Thanks again everyone.

I think it's cool to get a citrus tree from store bought twigs. I tried to root a satsuma twig I got from whole foods but it didn't take. This got me wondering however, would getting a tree like that violate the citrus quarantine rules if it came from a restricted state? What if the twig has the HLB virus? I read where even floral arrangements can't included citrus from quarantined areas. Maybe these are excluded? Just wondering about it.