I have a tip, for the Nectar Making Vizard of Vine Challenge, you need 400 bunch of grapes to be turn into nectar. The trick to completing this is to plant the grapes yourself and harvest them yourself. Of course, during the course of the process, I advice that no one should travel, since it will reset the challenge.
So, I find Renoit Grapes to be the best choice for this, this is due to the fact that:
a) It has a short grow time, with life fruit as fertilizer its around 4 days.
b) Combine with 5 apples it makes an amazing nectar.
Since the challenge require use to have 400 bunch of grapes, so we need around 15-16 bushes of grapes. You can choose any grapes type, but personally I prefer Renoit Grapes. The Cherimola Blan and Avolarino variants are also fine for me though.
Start with making your Nectar maker plant 15-16 bushes of grapes, then fertilize the grapes with life fruits.
If you have gardening a supermaxed by previous immortal (like me), you can use the immortal to fertilize the grapes instead.
Instead of using "Tend Garden", use "Harvest" when collecting grapes. This will stop your nectar maker from getting anymore skill experience and overwriting the previous immortal's supermax. Have the gardener to weed the garden if necessary.
I hope this helps! Good Luck.