Why?

I second citrange, what's the point? Can it be done, probably. But why?

Even if the 2 are touching each other they will separate very easily and you will have 2 trees. I vote to separate and grow 2 trees.

Aesthetic purposes

I can't see the point.
But if you wait until they are a bit older, you could take a thin slice off each stem so that when tied together they meet at a flat surface without a gap. They will then join more strongly - effectively a long graft.

http://en.wikipedia.org/wiki/Axel_Erlandson

I agree with those who said it would be better to separate the seedlings and have two trees. They do separate very easily. I did this for the first time just last night. I practiced on a batch of key lime seedlings I started at the same time, and then I separated my very special birthday grapefruit seedlings, both of which grew from one seed. The seed is from a store-bought Rio Star Texas ruby grapefruit, so I assume it's a Rio Red. I began incubating it in a wet paper towel on February 5th, and it showed its first root on my birthday, February 13th. Then a couple of days later the seed showed its second root, at which point I planted it in a styrofoam cup.

Here is a picture of the seedlings right after I separated them. Eventually of course they will be planted in separate pots. Okay, I admit it--this post isn't exactly on topic and I just wanted to show off my new seedlings!

This post was edited by raksha on Sat, Mar 1, 14 at 14:35

Oh no it's okay to show enthusiasm about your new seedlings. Yeah I'll probably separate them. I hear Key limes are slower growing, is this true?