Josh: Do you know any other method to check the soil dampness? (I can't use the "finger test" method because the soil is so hard and full with roots so it's impossible to stick my finger down there). Johnmerr: Thank you for the suggestion! I will give it a try. There is another thing. There is a instruction tag came with the tree that says I should only repot it after 2 years. However the soil doesn't seem to have good drainage to me (when i water it, the water doesn't go right down but stay on the surface of the soil for a few minutes, I then have to wait until it's absorbed by the soil then repeat again until I see some water running down the drainage hole at the bottom). Is it normal so? Or should I repot it and replace it with better soil?

Okay. First thing - is this little lemon tree getting sprinkled? If so, this is part of your issue. Citrus do not like to be in the path of sprinklers. They do much better with a deep watering via drip once or twice a week (depending upon how hot the temps get). If you're close to the beach, you probably will not have hot enough temps to water more than once a week. Lilly Miller citrus fertilizer is fine. It does contain micronutrients. Vigoro Citrus & Avocado fertilizer with micronutrients (that is the key for you) is also fine. Actually, the best NPK ratio is 5:1:3, but it's hard to find. As long as you've got a higher N (nitrogen) than P or K, as citrus are heavy nitrogen feeders, and you've got micronutrients included, you should be fine. Humic acid will also help, so look for that in your ingredients line up. I would recommend Grow More Citrus Growers Blend and mix it up as a foliar spray to help give your tree a good micronutrient feeding. Repeat in 3 weeks. Do your foliar spray in the evening. I would concur that you're probably looking at a micronutrient deficiency, possibly magnesium. Usually, you'll see a micronutrient deficiency with too much water and cold temps, so I would definitely check the roots of your lemon, to make sure it's not sitting in a puddle of water (i.e., in clay). Even though you're by the beach, you can still have pockets of clay. If you're in more sandy soil, then you're seeing an issue with both macro and micronutrients not staying in your soil, but washing out. If this is the case, then make a nice well around your tree out to the drip line. Fill with some worm castings and then top with compost. Keep both away from the trunk to prevent rot. Put your fertilizer in the well and water in deeply. Fertilize every 3 months and also I would recommend a foliar application with Citrus Growers Blend as well until your tree greens up. Patty S.

Here are three pictures from this afternoon. The small leaf in the container must be a newly dropped one some time today. I am in central WI. Our weather this week looks to range from 82F-88F with majority of days on the lower end. The lows are in the mid 60s. I will note that I do not think the tree has grown. At least there appears to be no new buds. I've had it for just over 3 weeks now. Note: I removed the stake once and the tree was angled about 45 degrees when I went out to look at it one day. I have it re-staked and tied near the very bottom now. This post was edited by Neurosci on Fri, Jul 5, 13 at 19:48

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.