Dont apply to seedlings you might bring indoors (you'll be sorry).

I also use kelp meal/compost tea for more micronutrients.

If used heavily it can make seedlings grow too fast, keep that in mind if they still have awhile before putting in the ground.

Apply after a rain or watering.

I put on the root zone rather than foliar feed.

some years when its cool I have found this isnt enough P so I supplement at least 2 feedings with some kind of soluble P source.

Early P is very important to early fruit formation.