Ahh. I've been cart shopping every day it's there and got most of the CC stuff but no seeds. Well then, all hope is not hanging on the stupid artifact seed then. Come onnn RNG, sell me the seeds!
The easiest and fastest way to get some ancient seeds is killing grubs in Mutant Bug Lair with double Burglar's Rings. If you still don't unlock it, try killing grubs at low levels in mines instead. Actually you will need two ancient seeds. One is for the museum and the other is for crafting the ancient seed recipe in Craft Master Achievement. Besides, the Traveling Cart does not sell ancient seed artifact.
True. I'll be able to plant ancient fruit in my greenhouse now, but it doesn't help at all with finishing the museum. Not terribly worried about that for myself, but getting a plantable seed from either the cart or the seedmaker will not do anything help the OP with their last remaining artifacts. I was just noting that it is in fact possible to get the plantable seed without the artifact.
When you turn in the ancient seed to Gunther at the museum, you get a plantable ancient seed and the recipe on how to convert any more of the 'artifact' versions of the ancient seeds into plantable ones.
Well after the wizard's quest, the sewer bugs came through with flying color(ed bug meat) plus one ancient seed artifact, as advised. Got the one seed planted and the cycle to multiply that begins. It's good that it will keep growing and dropping fruit for-eV-ar in the greenhouse.
I finally found the palm fossil and the museum is complete!!!! You get a stardrop for doing it. Nice.
Don't know if this is very well-known since I'm pretty new in here, but you can also get a stardrop for giving the statue in the Secret Forest something mighty sweet (and you can guess what, eh?).
You can also buy a stardrop at the fair for a 2000 fair coupons, I think, and I believe there's one in the sewers from Krobos for 20,000 gold, level 100 in the mines from a chest, from Willy with the Master Angler Achievement, and from your spouse at 12/13 hearts, this only works once if you divorce and remarry even to someone else you won't get another stardrop. The only one I've never gotten is the Master Angler where you need to catch every fish, buying them from the traveling sales lady doesn't count. I doubt that I'll ever get this, I just can't seem to get the legend fish.