Cai unlocks crop farming in Chapter 6 of his path, through a quest and world-map tutorial after the chapter's opening scene. Once it is available, plant a crop you already own on an empty plot, let its growth gauge fill and pass the field to harvest. Fertilizer favors a location's rare crop, so leave it off when your main goal is reproducing the particular crop you planted.
This guide focuses on Cai's agriculture rather than using farming as a catchall for experience or currency grinding. Crops have several documented uses, and the right planting decision depends on which one you need next. The Cai route overview can help place the unlock within your route, while the steps here explain how to manage the field once it becomes available.
Unlock the tutorial before looking for a field
Game8's crop farming guide identifies Chapter 6 as the unlock point. It describes accepting an NPC quest after the opening cutscene and then visiting the world map for the tutorial. If the Farm command is not available earlier, that missing unlock is a more useful explanation than assuming the empty node is broken.
In Part I, agriculture is Cai's distinctive route mechanic. Faerghast's harvesting walkthrough likewise places its introduction in Chapter 6 and contrasts it with obtaining crops through search spots or crates. Do not expect another protagonist's early route to present the same field-management options simply because the world map contains similar-looking locations.
Secure the first crop you want to multiply
You must possess the desired crop before planting it. The crop guide lists merchants on the world map, glowing search spots in bases and breakable dungeon containers as ways to obtain crops. Your first specimen is therefore an input to cultivation, rather than a reward you can request from an empty field without owning it.
Read any item request before choosing that specimen. If a quest, trade or other objective needs a particular crop, confirm its name against the item in your inventory instead of planting a superficially similar ingredient. For objectives connected to another character, the recruitment guide is a useful place to keep the broader requirements in view while you build the relevant stock.
Plant on an available world-map plot
Look for an empty pentagonal node without another activity icon. Travel there, select Farm and choose the owned crop you want to plant. The node changes to show a crop icon and a gauge, giving you a direct way to track the active field from the world map.
Planting is only the beginning of the process. Spend time on other useful exploration or Dagsion activities while the gauge advances, then return when it has filled. This makes placement a route-planning decision: a field you can revisit during trips you already intend to make is more convenient than one that repeatedly demands a separate detour.
Make the fertilizer decision deliberately
Fertilizing a planted field increases the chance of receiving the rare crop associated with that location. Both Game8 and Faerghast distinguish the rare crop tied to the plot from the crop chosen as the planting input. That means fertilizer is not simply an unconditional improvement to the quantity of whichever crop you selected.
If your objective is more of the ordinary planted crop, their advice is to avoid fertilizer. If you are seeking the location-specific rare result, use an input crop you can spare and recognize that the resulting harvest may be different from it. A rare harvest remains a chance-based outcome, so allow room in the plan for another result rather than counting on a certain payout next visit.
Fertilizer can be found at Dagsion's Stable or obtained after an unsuccessful animal capture, according to Game8's guide. The same source notes that its effects can remain on a plot after a new planting before fading over time. Inspect the field's current situation when changing objectives rather than assuming a replacement crop automatically removes every earlier treatment.
Harvest without discarding the remaining planting
When the growth gauge is full, passing the field collects the available harvest. Game8 describes either obtaining more of the planted crop or receiving a rarer crop, followed by continued growth and additional harvest opportunities. A ready harvest is therefore different from an exhausted field, and your first collection does not automatically require an immediate replant.
Faerghast adds a practical travel distinction: walking across the plot collects the harvest, while a carriage journey passing over it does not. If a planned trip uses a carriage, do not count a field along that line as already collected. Include an actual walking pass when the harvest is part of the objective you are trying to finish.
Replace a crop only when the new goal is worth it
The New Farm option lets you switch to another crop while an existing planting is still active. Doing so gives up the remaining value of the previous planting, according to the crop guide. That tradeoff can make sense when an urgent request changes, but it should be a choice rather than a reflex after every harvest.
Renown also affects how many plots Cai can manage. Game8 lists an initial single plot, a second at Renown level 7 and a third at level 9. If the limitation is available field capacity rather than missing seed stock, consult the Renown guide and check that progression before trying to open extra fields through repeated planting commands.
Give the harvest a specific job
Crops can satisfy item requests and can be exchanged with Vandahl Trading Co. merchants for equipment. They can also restore HP and magic uses at dungeon Rest Spots or world-map Feast nodes, with the menu displaying the recovery amount for the relevant character. Compare the intended trade or recovery need against the stock you have before committing all of a useful crop to another purpose.
Game8 also identifies crop feeding for the Pale Raven as part of entering Bird Time. That activity connects food supply to support development rather than direct combat equipment, which can matter when your immediate plan involves relationships. Keep the support guide alongside the farming objective so a productive harvest leads into the activity you actually intended to enable.