Fred Clarkada After Dark `SVO Black-Pearl` when do i start watering?

[Pixi]

Hi there,

I bought this teeny tiny Catasetum baby in February. it's new growth is doing fine, roots are just starting to grow.
when i got it it still had a yellow leave on the biggest bulb that fell of the day after.

When do i start watering? after the roots are more then 3 inches long or when the leaves appear?

This is my first Catasetum i don't want to kill it