I've tried sponging with make up sponges before and haven't had the best of luck. Truthfully, I've only tried twice and the second attempt was better than the first. Anyways, I tried something different for this mani by taking the brush from a polish I never use and cutting it super short so I had more control. So I guess it really wasn't "sponging". Then I just blended, a lot.
I like the thumb, ring and pinky, but I lost the gradient effect on the other two nails, sort of.
I started with a franken aptly named "Jaded".
Then I used this arsenal of greens and teals;
left to right;
funky fingers "peacocky"
sinful colors "mint apple"
funky fingers "wild child"
sally hansen HD "pixel pretty"
funky fingers "bizerk turq"
& the last one is the brush I cut, but some of that made its way into the mani.
Then I just tapped and poked my nails like nutso. I put a drop of each onto the back of a fauxnad plate and just kept dabbing all over. I love blending :D