Tomatillos are a lot like tomatoes, but may love heat even more. The fruits may not drop off, but they'll probably stop growing with night temps below 55-60.

I live in Denver, (z5) and have grown tomatillos for a few years running. The first year, I experienced pretty much the same thing - tons of flowers - no fruit. Eventually, I just stopped paying attention and decided that the plants were attractive enough to leave in the garden and I went on with my summer. Then came August, and one day I noticed there were literally hundreds of tomatillos in various developmental stages. By the end of August, I was overwhelmed with tomatillos. They were on the plant, all over the ground, piled on my counter, and I was running out of ways to eat them. These days I only grow two or three plants, which is just the right amount for me. I generally use them in chili recipes, substituting chopped tomatillos for half of the tomatoes.

Since I get free limes and lemons quite often, I use fresh juice quite a bit instead of bottled. I know they say not to but I see no point to throwing out a good fresh juice supply and buying preserved juice in a bottle. I don't like vinegar much so often substitute lime juice for some of the vinegar. I think the lime juice is more acidic anyway. I think you can usually leave out hot peppers in a canning recipe since peppers are low acid and the other stuff is probably higher acid.

The fruit grows in the papery husks. They can take a long time to become large enough to fill the husk. In the meantime, it is easy to think nothing is growing inside of them. As I recall, there are mixed opinions on whether you need more than one plant. Here's info and a link from a past discussion: "Studies show that some varieties are readily self-pollinating while others are not. Some varieties require a wider range of cooler temps to self-pollinate, and some plants it seems will never produce fruit regardless of the growing conditions. So there are no absolutes about them." Check the last post in this thread: http://forums2.gardenweb.com/discussions/3651678/odd-problem-with-tomatillos-only-one-plant-producing-fruit?n=9