How is crossbreeding Jute and Tantalplant?

[Vidu]

I use Ivory's Advanced, but am wondering if there are better seeds to use than Tantalplant, so I can harvest all 8 and not only th 5 Jute, and if there are any combinations that are better than others.

What do you mean by "harvest all 8"? You can - and should - harvest all 8 plants, just staggered (aka: harvesting the 4 that are ready for harvest, replant those, wait 1-2 days for the other type of plant to be ready, harvest and replant those). After your initial set-up where you might choose to destroy the first plant you put in the ground, you should be in a loop that you can keep up for as long as you want.

The type of Premimum Chocobo Food seed shouldnt matter - so Tantalplant isnt better than Sylkis, Mimett or Phasana. One advantge of jute in my book is, as I explained, that you can use those 4 types of seeds or any combination of them, depending on what you can get a hold off (aka: lets say you're crossbreeding Tantal-seeds yourself, but one harvest falls short. In that case you can buy the cheapest of those 4 seeds from the marketboard instead of being locked to Tantalplant).

As far as I'm aware all Thavnair Onion cross breeds between a Premimum Chocobo Food and some "premium plant" (jute, galzenut, broombush etc.) are equally good - or bad, if you will. Theres not advantge to using one premium seed over the other, except for maybe the usefulness of the actual crop in the end - different chocobo foods might sell for different prices, aswell as different "premium" crops being priced differently.

Onion breeding will always suck - at least a little bit - and you'll always have to deal with not getting the seeds you want.

I'm currently in the process of supplying my FC with Onions, so heres what I'm doing:

I'm using 3 beds at the moment, though 2 would be enough, the third one is a saftey measure.

First bed:
Jute x Chocobo Food => Thavnair Onion/Shroud Tea alternating with Jute x Mandrake => Jute
I started with the Jute x Mandrake cross, which allowed me to start by planting a throw-away seed (aka Mandrake) - that cross gives me my jute-seeds back. Each time mandrakes are ready, I replant with chocobo food and vise verca. Jute gets replanted with jute as soon as ready to harvest.

Second bed:
Thavnair Onion x Shroud/Coerthan Tea => Sylkis bud/Mandrake
Its not a great cross for premimum chocobo food, but it also gives me mandrake-seeds and is efficient enough for my purposes most of the time. You could use other seeds to cross with the onion to get a different premimum chocobo food seed, but I'm getting Shroud Tea from my first bed and Coerthan Tea is super easy to gather in bulk, so I went for this one.

Third bed:
Coerthan Tea x Chocobo Dye Food => Sylkis bud/Mandrake
This one is optional and more a type of "back up" if the second bed doesnt produce enough seeds. Since the food thats used to dye your chocobo only takes 2 days to grow, its quick and I probably wont keep this in an instant loop but rather plant whenever I'm a bit shorter on Syklis buds than I'd like to be.

This might not be great for "mass producing" Thavnair Onions, since they're being used in a cross rather than just planting a full garden bed with them, but once you have the initial seeds ready to set this up and arent super unlucky, you can keep this up forever (and maybe even get some "bonus-seeds" that arent going back into this cross).