SLC, just my 2Ã‚Â¢ and what I'm doing (with a climate probably not much different from yours and even weed seedlings are only just now showing up
This is the 1st day for the tomatoes to be outdoors. I suppose you can say they are hardening-off but, mostly, they are outside to make it easier to water them. Some are in 4-packs and the others have already been moved from 4-packs to 4" pots. They have spent the last few days out of the heated greenhouse and in a unheated plastic tunnel so they are somewhat used to a range of temperatures.
When it rose above 50Ã‚Â°, I moved them into the most protected area of my yard. The sun was shining on them for the 1st couple of hours but they are now in the filtered sunlight of a tree, that is yet to leaf-out. At noon, the temperature was above 65Ã‚Â°. There is only a slight breeze. They will have direct sunlight again during late afternoon so I'll move them out of the sun & into shade. Soon, they will be back in the plastic tunnel where they will have to remain during the nights, certainly, for the next few weeks. I doubt if the weather will be good enough to bring them outdoors again until next week.
The only transplants I have in the garden right now are onions and a few of the snapdragons. They can both take a frost and that is what I expect - more frosts. Both of the onions and the snaps were harden-off in that same "Sweet Spot" in my yard. They were also moved out of the direct afternoon sun until the final couple of days and spent their nights, back under plastic.
I would be comfortable moving cabbage and broccoli into the garden but the seedlings aren't quite far enough along so they are being "babied" here at home for another week or so. The same is true with the lettuce and bok choy starts, altho' the bok choy is already in a garden bed, covered with hoops & plastic film. I will have lots to move into other beds soon.
Plant starts are babied around here - as best as I can. Things like peppers and eggplants won't be coming out until the very nicest days. I don't really want anything
to be exposed to freezing temperatures even if they can survive the cold. I don't leave them outdoors at night during the hardening-off period except, maybe, the last night or 2. If they are tough enough to stay outdoors 24 hours - they are tough enough to go into the open garden.
Both cold and high temperatures and strong sunlight aren't their friends so they are introduced to those conditions slowly. Strong winds, also - there's just no value to be gained by slamming them around.
After a week or 2, they will be out there and on their own.
Oh, you can provide some protection in the garden - like shade from the sun. But, I seldom do that. At some time, you have just done all you can for them - they've got their feet
in the soil - and, it is time to stand on their own but it is a slow introduction at 1st.
We are each other's harvest; we are each other's business; we are each other's magnitude and bond. ~ Gwendolyn Brooks