Luca and the Luca Arbor: How Planet Growth Works

What Luca is and where it comes from

Luca is the growth resource for your planet. It is not a currency you find in a wallet and it is not sold in a shop; it accumulates from the two things the game is actually about — relationships with Neighbors and time spent out in the Starsea. Neighbor bonds, Planette progress, and voyage discoveries are the steady sources, and a progress guide written during the test describes Luca as thinning out past the early thirties, which is the point where the easy milestones are behind you.

The Luca Arbor is where that resource is spent. It is a single tree on your home planet with a level counter, and the level is the closest thing Petit Planet has to a player level. Everything else — plots, terrain tools, the ability to dig, the chance of a fourth Neighbor — is keyed to it.

The spelling matters if you are searching: the game and the wiki use Arbor, not Arbour. Some fan writing uses the British spelling; it is the same structure.

How the Arbor gates content

The Arbor is a technology tree that happens to look like a tree. Levelling it does not give you a stat bonus; it opens a verb that was previously unavailable. Before level 2 you cannot farm at all. Before level 5 there is no reason to look for soil mounds, because the game will not let you dig them. Before level 13 the highlands are not part of your planet.

That makes the Arbor the answer to most "why can't I" questions in the first week. If a tool, a terrain option, or a Neighbor invitation is greyed out, the usual cause is an Arbor level rather than a missing item.

Which Arbor levels unlock what

These are the milestones recorded during the Final Beta. Levels not listed here were reached by testers but did not come with a documented unlock.

Arbor level	What it unlocks
2	Farming — soil becomes workable and crops can be planted
3	Four additional farm plots
5	Soil mound digging, with four mounds and six ore piles refreshing daily
13	Highland terrain, which brings additional species
17	A chance to meet a fourth Neighbor on a second Starsea trip

The level 5 unlock is the one players underuse. The daily mounds and ore piles are the source of meteor ore and the other minerals that Neighbor furniture and upgrades consume. They refresh every day and they are small, so a lap of the planet after unlocking digging is worth more than it looks.

Two other systems came online during the test without a published level attached: the weather system, which appeared around the third day, and the Planet Maker app, which unlocks on day three and is what finally lets you batch-lay paths instead of placing them one at a time. If you are trying to date one of these to a specific Arbor level, the in-game app list is the reliable source, not a guide.

How fast a level comes at a normal pace

A tester posting daily progress reached 6, 6, 9, 14, 14, 19, and 19 across the first seven days, which works out to a level roughly every day or two and a visible plateau on days when the story was waiting on a build. The same posts record the plot count moving with it: 39 plots at level 9, 43 at 14, and 51 at 19.

Treat that as a pace, not a schedule. Those runs came from players logging in at reset and pushing story tasks immediately; a relaxed player will see the same unlocks several days later and lose nothing but the calendar. The one number worth planning around is that the plot count only rises at certain levels, so a farming plan built for 39 plots has to be revisited when the Arbor reaches 14.

Do Luca Fruits change the planet permanently?

Yes, and that is the point of them. A Luca Fruit is the final reward on a Neighbor's Planette ladder, and it grants a lasting change to your planet's appearance — the recorded examples include cliffs, rivers, clouds, waves, and star or constellation decoration. Frostia's ladder is the documented outlier, handing over a Star Anchor ticket at the fifth stage instead of a Reaction.

Because these are cosmetic terrain features rather than temporary buffs, they do not expire and they do not consume resources. They also cannot be previewed before you commit, which is the one real cost: you are choosing the shape of your planet based on a Neighbor's theme rather than on a plan. The Neighbors guide lists each Planette ladder.

Can you undo an Arbor choice?

There is no respec in the Final Beta, and HoYoverse has not announced one for launch. In practice this matters less than it sounds, because the Arbor has no branching: levelling it does not lock you out of a competing branch, it just adds unlocks in a fixed order. The choices that are hard to reverse are the placements — a building put down before the Planet Maker app is available cannot be moved until that app unlocks, which is why the day-three unlock is worth waiting for.

Planette investment is the other semi-permanent decision. Archiboos spent on one Neighbor's ladder are not refundable, and ladders advance in a fixed sequence, so a player who spreads Archiboos across six Neighbors will see six slow ladders instead of two fast ones.

What to prioritise

The two styles of play want different things from the same tree. If you are pushing progression, community progress guides recommend concentrating on Yunguo's growth, because the Cultivator's ladder feeds the farming loop that everything else depends on. If you are playing for the cozy side, spreading attention across the Neighbors you actually like is the better use of the same Archiboos — the rewards are cosmetic, and cosmetics are the point.

Either way, the Arbor itself is not a decision. It is a gate. Feed it, and the planet opens.

Baseline: Final Beta 0.95 (Starsea Call). Level milestones and plot counts come from daily progress posts during the test; the level attached to the weather system and Planet Maker app was not recorded.