I would probably use a dark color for a first border an then maybe a lighter one for the final border.

What a wonderful idea, thank you. And thank you to everyone else who replied.

I do like the idea of the white inner border, because it "floats" the center design and gives the eye a rest, before a more colorful outer border.

How about "auditioning" several combinations - you don't need to cut anything to get the effect - just lay the blocks out over the fabrics -

Take a few pictures and then compare the pictures.

Sometimes it is easier to "see" an effect on a photo than in "real life"

Don't know why that is, though.

I find that if I make a multi-colored quilt, then put a blue border on it, the quilt becomes a blue quilt. The border pulls out all the other blue and makes the quilt look mostly blue. So if this were my quilt, I would use the turquoise type color in the bottom right, because that’s the color I like best in your quilt.

I see this quilt with a green border on 2 sides and an orange or red family on the other two sides and no white stop border. When I am questioning which color or how many borders I will like, I lay out the fabric in the width that I think I would like for the border right next to or slightly underneath the completed top and take pictures. DON'T cut anything until you make a decision. The pictures really help me see the whole quilt and make a better decision. If I don't like any fabric I have then I take the pieced top to the fabric store and test fabric colors there. I still take pictures & view those before I make the final decision. NOTE: If you do decide to take it to the fabric store, I would think about running a staystitch around the outside perimeter. That will keep your outside seams from coming apart. My stay stitch line is about 1/8".from the outside edge.

Your quilt is lovely and you have had some great suggestions. Because it's not assembled yet, may I suggest straightening out a couple of the blocks with directional fabric that looks like stripes. There are a few going vertical and others are horizontal. Because you want a sunset look, if changed all to be horizontal I think it was flow better when complete. Can't wait to see what borders you choose. Good job!

As you see, you will get lots of different suggestions. Here I go with mine. I would first consider what you re going to use for your back. I like to use that color either in my border or as my binding. I like the what border even though there is a lot of white in the top already. It keeps the "theme" or the look of the quilt and border looking consistent. But, I would suggest a narrow color border first, then the white.When I first looked at your quilt I saw green but that could just be because of the photo. So if it was my quilt, a narrow green border then a white wider border but not too wide. If you wish the borders to actually make the quilt larger expand both the inner border with just a little and the same with the outer border.

There you go my opinion. Put it in the bag, mix it up with the other ideas and do what feels good to you. You have a lovely quilt started and oh, so many more quilts in your future to play with.

I agree. I might audition a narrow white inner border with a wider turquoise outer border, take pics and see how I like it. Look at it from across the room and also as a pic on your phone. This will help you get the wide-angle lens perspective. Lovely quilt!
By the way - what's the name of this line of fabric?? I've been looking for it but it's hard to find without the name. 😜

I'm probably in the minority here, but I'm not a border person. I don't add them whenever possible. That said, I'd do a white binding.