Be careful when they are small. Wait till they start putting out some leaves then the 10-10-10 or the 6-4-6 is ok. They are hard to over fertilize when they are growing.

From my experience it is good to fertilize regularly when they are young but small amounts. They like tofeed to grow stronger. During cooler months space it out to once a month. Warmer weather once every tgree days mix in a little in the water.
If you over fertilize the leafs will turn a little brown. So keep an eye on them.

Tommyg