When should I plant outside?

When should I plant outside?

I'm working on my first vegetable garden. I built two raised beds and filled them with a mixture of vermiculite, compost and peat moss. My seedlings are started inside and some are looking stronger than others. I'm wondering when I should put them outside. I live on the zone 5B-6 line. The last frost date is predicted to be May 24th, but it has been pretty warm, though today it is 50 degrees. No frost on the grass in the morning. The seed packet directions have no mention of starting seeds indoors, but the garden center said that in this zone, if you don't start indoors, you won't harvest before frost in the fall. Here's what I have started inside: Spinach Lettuce Peppers Basil Parsley Beans Squash I also have seedlings for a whole bunch of annual flowers I also want to plant onions- not sure when to plant those either? When should I move the seedlings outside?
Pretty tulips

Pretty tulips

Dodged the frost bullet last night.  The tomatoes are fine

Dodged the frost bullet last night. The tomatoes are fine

Hello my new friends!

Hello my new friends!

Ice on herb plant…

Ice on herb plant…

a few of my favourite things about my room

a few of my favourite things about my room

Lenten Rose (Hellebore)

Lenten Rose (Hellebore)