If your porch has a wood deck you'll need to cover it with something to stop the cold air from blowing in underneath. Another layer of porch decking laid crosswise to the existing boards, leaving no spaces between them, would still allow drainage. If you have a concrete porch, you might just put down some bricks or pavers to insulate the floor a bit.

Don't forget hooks for hanging some lush ferns and space for a chair and table, so you have a place to sit, read, and enjoy. Cheryl

You're right, responses can get a little slow around here.

I think you'll get more action if you provide more info. Posting a picture of the gazebo would answer lots of questions. Then include how you plan to use it. (Big difference between providing a year round greenhouse for
orchids versus one that will be used for starting veggies). There can also be a big difference if you want to optimize the area for your plants or create a nice sitting area like Cheryl suggested.

You'll find lots of good info here.