This time of year, a sprinkle of limestone, and a good balanced fertilzer is all they really require.
Never being one to waste, I water my houseplants (200+) with a good quality fertilizer and then pour off the overflow from their dishes into a jug. I then pour the contents of that jug (usually 4 fills per watering) over the various clemmies in my yard. I'll only do it until they start to flower, and I'm seeing flower buds on some already so I'll have to stop soon.