I created a makeshift greenhouse and have been putting my plants outside when the weather is warm and sunny. I put a clear plastic tarp/sheet over a couple of A frame shaped wood stands my dad had outside. I've secured the plastic but the bottom doesn't completely cover and prevent wind so I took another plastic tarp that you can't see through and wrapped it around the bottom and placed pots and stuff around it to secure it to keep the wind out. My plants are doing well but I'm struggling with space indoors and want to know when I can place them outside.

I've read about last frost dates being around May 9th (?) I've gone to the Almanac.com site and found this for my zone

Climate Station

Last Spring Frost (50% Probability): April 29

First Fall Frost (50% Probability): October 29

Growing Season: 182 days

ERIE AP, PA climate station

I would assume this information relates to placing plants outside permanently and overnight but what about with protection? If I was going to leave my seedlings outside overnight (after hardening them) in my protective shelter I would make sure it was completely sealed all around so no air could get in. But I've also seen these 'ghetto greenhouses' where you use a pop bottle to start seedlings. Would something like that provide enough protection for placing seedlings outside before the last spring frost date?

I know it's getting close but I moved home with my folks and my entire one bedroom apartment is in one bedroom and no space in the house for my stuff (most of my old apartment was garbaged) so I'm looking forward to getting my plants outside to get some room back and to stop having to use so many lights inside for my seedlings (so not looking forward to that next hydro bill).

Also since my plants are enjoying the time outside when it comes to hardening them do they have a head start? Or should I do as I've read, leave them in shade for a couple hours a day increasing it daily then leaving them out all day before shifting them into the full sun for a few hours a day (increasing that time) before I leave them outside all the time? I'm doing more reading and planning on how I'm going to harden them but I'm wondering if I have a shelter if that counts for some of the hardening stage and I can start with taking the plastic off for an hour or two in the morning for full sun?

I wanted something like a greenhouse to get plants outside sooner that haven't been hardened off but is the purpose of a greenhouse to host the plants all season long? I plan on moving my plants to hanging containers (the ones I can) or just raised garden beds but I thought of building a cold frame or more permanent greenhouse for next year. If I do so would I plan to plant stuff in them that would stay in there all growing season long?

Any and all replies are greatly appreciated!!!