Ever heard of spring?
It's the main natural flowering season for all citrus.

ok smarty pants..lol
Even un spring I never get the amount of flowers that I have seen on them as when I bought them.......

You need to use citrus fertilizer specifically. Citrus is unique in that it must have trace minerals in order to flower, fruit and hold fruit. Too much nitrogen will result in lots of great green leaves, few flowers.

Containers need feeding monthly. I also add a teaspoon of vinegar/gallon and the trees really love it. They really are able to take up the ferts when acids are added.

My calamondin blooms several times a year. I encourage blooming by feeding it with superphosphate (1 tablespoon), Epsom salts (3 tablespoons), Miracid fertilizer (2 tablespoons) and 8-8-8 fertilizer (1 tablespoon) with trace elements. Then water, water, water. It doesn't take much superphos or 8-8-8. My cal is on a 30 gallon pot, about 7 feet tall and 3.5 feet wide. It is in the greenhouse right now after being outside all summer. It has so much ripe fruit it looks like a decorated Christmas tree with small orange balls. If I were you, around 8 weeks before last frost, I would fertilize with this combo. Be sure to consider the size of your tree and adjust the amount of fertilizer.

Mike, over fertilization (with N) is very commonly the problem with poor fruiting performance of container plants.

Rhizzo, what do you think of rhizos answer. Trying the same thing, just less on the amounts for my trees are in5 gallon containers?
They are very healthy. Green. Even in some flowering stage.
My grapefruit tree has just started to blossom. But It is growing new growth along with a few blossoms. I have about 20 buds that are about to open. But I also have a lot of new growth of leaves at the same time. I would of love to see double the blossoms, and less leaf growth. It's just not loaded with blossoms like I want them to be. Or should I just be happy with them and let them do their thing. Am I asking to much from some of my trees? Thanks alot. And thanks tsmith and others for your suggestions. I like the vinegar in water one. I will try this sometime if I notice any nutrient problems in the color of my leaves. Thankyou again! ;-)

Sheesh, sometimes I think my brain is half dead or thinking faster than my typing on this forum. Either my spelling is incorrect, some of my thoughts don't make any sense, my ideas don't connect, or I say wrong names..HELP!!!
Rhizzo, what do you think of "tsmiths" idea?????
Lol
I think I have no spelinging errors in this post!!!lol

Background: I bought a very small Valencia Orange from Stark Brothers two years ago (along with an order of fruit trees). First year was strickly indoors, not the greatest growth. This last summer I moved it outside.

I purchased a lemon and a lime from Home Depot during a trip to CA (they had Four Winds tags on them) and brought them back to Utah.

Care: They seemed to be doing okay, and I fertilized all with a citrus fertilizer when I got home in August. I moved the orange to a larger pot at about this time, using a pot I had similar in size to the ones from HD/Four Winds, but the orange isn't nearly as large, but lots more leaves. When I moved them into a sheltered area (no direct sun) to prepare them for winter, the lemon lost all of its leaves - may have also been a lack of watering issue as well. At any rate, I moved them to the garage next to a north-facing window and the lemon produced all new leaves. A few weeks later, the lemon and orange produced quite a few blossoms. Of course, the blossoms quickly dropped, but the orange has continued to blossom with one or two here and there after I moved it near a second floor south facing window.

Analysis: I thought the blossoms came because of the changes in settings (cool/cold to warm) as if it was going into spring? At any rate, it was my first use of a citrus fertilizer and the first time that the orange had blossomed in the two years I've had it.