Well, shortly after the post, I realized I needed to take action, so I repotted both lemons right away. They were originally put into 12 inch terracotta pots, but I reduced the size of one to a 10 inch terracotta pot (the second stayed in the 12 inch). When I trimmed in the original potting, it was less than an inch off the bottom. I repotted with 1/3 part of cedar shavings (as recommended by Four Winds Growers) and gave them a GOOD SOAKING of water. The roots were quite dry, no root rot had set in, and they were very healthy. The roots looked the same as when they shipped 6 days prior. The GOOD NEWS: the next day after repotting and heavy watering, a few of the buds opened up! They smell fantastic. I imagine the plant wouldn't open buds if it wasn't bouncing back? They've also bee in full sun since Sunday. There are still some yellow leaves, and I lost a few more (maybe 1 a day from each, rather than 6+ a day from each), but I take it they're recovering? After seeing the buds open up, I gave a light feeding and another watering today. We're having night lows in the 50's, so I'm leaving them outside at night now too. Are they on the mend?

There is no difference (NPK) between 9-3-6 and 6-2-4, or 3:1:2 other than the grower's hand on the measuring spoon or the frequency with which the fertilizer is applied, and it's not the fertilizer's NPK %s that determines the amount of N the plant gets, again it's the hand of the grower. 9-3-6 is an excellent all-purpose fertilizer for virtually anything grown in containers. If the grower wants to supplement the N or K, he can easily do so by adding to the fertilizer solution small amounts of urea or ammonium nitrate for nitrogen, or KCl for potassium - very simple and it adds a great deal of versatility to grower's nutritional supplementation program should the grower wish to do any fine tuning. I don't, and I've posted hundreds & hundreds of perfectly healthy and productive plants on these forums. By far, the most efficient pathway for getting nutrients into the plant is via roots, and the cuticular waxes in citrus leaves makes foliar 'feeding' relatively ineffective. Additionally, foliar feeding is most useful when the plant's growth rate is outpacing its ability to assimilate nutrients from the soil. That condition rarely occurs in container culture or when a program of regular applications of a complete fertilizer with all the essential nutrients plants normally take from the soil is in place. You're fine with your 9-3-6, April. You just need to apply more frequently and possibly at a higher concentration. Al

Yellow-vein chlorosis (yellowness that follows the veins) usually means nitrogen deficiency while the blotch could be a micronutrient that's lacking. Citrus needs a regular fertilizer that's high in nitrogen. Dyna-Fro Foliage Pro and Osmocote Plus both work well for citrus plants. Edit to add: is the yellowness just in a few of your oldest leaves? I notice in the background there are nice dark leaves as well. Leaves do die and drop off naturally as part of their life cycle. If its just one or two I wouldn't worry. However, if you aren't fertilizing regularly you should do that anyway :)

I seen this already answered on an other citrus forum.