Sounds OK but I would have put some drainage at the bottom. This species, and tree ferns in general, like constant moisture but not soggy roots. So as long as the mix is free draining the plant should be fine. However, as Steve pointed out in the other post, you will need to up the pot size fairly rapidly. Honestly though, I've grown this species in the southeast and it was not a strong grower for me. You may be a bit disappointed at its growth rate for you.

Also, in winter, do not subject it to freezes below 20F. In fact, any freeze below 25F and I'd bring it in. Better to give the young plant a chance to grow and establish its first few years than blast it with frond killing cold. Once it is big and established, freeze events in the high teens for several hours will probably not kill it, but I'd be careful. This species is not as cold hardy as some people would like you to believe. PF

I don't like the sound of the grass clippings! Slimy, anaerobic, drainage-inhibiting, troublesome gunk. Even on a compost heap you can run into problems with grass clippings - I don't think they have any role in making up ferny potting media. Hopefully it's in such small quanties that you'll get away with it, plus it's nearly summer and stuff breaks down quicker. But for the future, avoid uncomposted green waste in your pots entirely.

Steve