Soil/fertilizer for seedlings.
Right now I have a little seedling forest growing in my window sill, I have Coast Redwood, Giant Sequoia, Douglas Fir, Engelmann Spruce and Colorado Blue Srpuce. They all sprouted in early to mid-March and all of them are in 8 oz paper cups with seedling starter soil. At what point should I fertilize them? When is a good time to transplant them into regular potting soil?