Your plants, your data

Picture someone who has kept their plants in a spreadsheet for three years. There's a column called "Plant", one called "Where", and one called "Last H2O" that gets filled in most Sundays. Forty-one rows, a few of them just "pothos (small)".

Or picture someone whose plants live in another app with no export button. Everything they know about their collection is a long list they can scroll through but not copy.

The first thing a new plant app usually asks of either of them is to type it all in again, one plant at a time. That's a lot to ask before an app has done anything for you.

The other end matters just as much, even though it's quieter. Someone has used Fern for a year and wants to stop. Maybe they're moving in with someone who uses a different app, maybe they've just had enough. A year of waterings, the photos of a monstera's first split leaf, the notes about what went wrong with the fiddle-leaf fig: all of it is in Fern. If getting it out is hard, that difficulty works like a lock, whether or not anyone meant it to.

Both moments live on one screen, under You, called Your data. Its first line is "Your plants are yours. Take them anywhere, bring them in fast." This post is about what that sentence turned into once we had to build it: how plants come in, what goes out, what happens to everything when you leave, and what we still haven't worked out.

One promise, two directions

We treat bringing plants in and taking them out as one feature, and the clearest sign of that is a file. When you export, your plants come out as plants.csv, and its columns use the names Fern's import already knows: Name, Species, Common name, Home, Room, Added, Water every, Last watered, Notes. Give that file back to Fern and it skips the questions about columns and goes straight to the review.

They also cost the same, which is nothing. The import's review screen says it plainly: "Import and export are free." On the free plan Fern looks after five plants with reminders, so a big import on the free plan doesn't stop at five. The plants past the limit rest. They keep everything, just no reminders, until you choose which five Fern looks after or go Pro.

Charging for either direction would have turned "your plants are yours" into a sentence with a condition attached. Reading a messy spreadsheet or a screenshot does use AI, which costs us something each time. So instead of a price there's a daily limit: 30 files or sets of screenshots read per person per day.

Two ways in

You can start from Your data, from the ••• menu in My Plants, or from an empty garden, which asks "Coming from another app?" and offers to bring them in. From there, there are two ways.

The first is a spreadsheet. "Pick a CSV from Files. Columns can be in any order." Fern reads up to 500 plants from a file of up to 2 MB, whether the columns are separated by commas, semicolons, tabs or pipes, and whether it's a spreadsheet you saved as CSV, another app's export or one of Fern's own.

The columns can be called anything. The names Fern uses itself are certain. Common alternatives like "Where", "Type" or "Bought" are recognised too. For anything else, Fern sends the column headers and up to three example values from each column, each cut to 40 characters, to an AI model and asks which is which. The "What can it have?" sheet in the app shows the kind of thing this handles: "Last H2O" and "Thirsty since" are read as Last watered, "spp" and "Espèce" as Species. It ends on the rule we care about most: "A name or a species is enough. Everything else is a bonus."

When Fern isn't certain, it shows its guess and asks about three columns, one at a time: the plant's name, its species and its room. The screen says "Show Fern which is which. It takes three taps."

Dates get their own question when they need one. A date like 02/10 could be the 2nd of October or the 10th of February, so Fern reads every date in the column first. A first number over 12 means day-first, a second number over 12 means month-first. When nothing in the file settles it, you see "How are dates written?" with Fern's best guess already picked, and two choices: Day first or Month first.

The second way is a screenshot. "Another app with no export? Screenshot its plant list (or a notebook page). Fern reads it." You can pick up to four photos for a long list, and they're read in order. Each line becomes a name, a species when it's said or obvious, a room, the last watering if it's written down, and notes. "Peace lily x2" becomes two plants. Lines that aren't plants, like a heading that says "My plants", are left out, and the summary says so. It reads something like "Fern read 14 lines and found 12 plants."

There was going to be a third way in: pasting a list as text. It was built, then cut before the feature reached the app. A list in the Notes app can be screenshotted as easily as copied, and the screenshot reader was written with exactly that kind of list in mind.

Whatever you give it goes to Fern's server to be read, and what was read is kept for one day. After that the rows are forgotten, and an import that was never finished is deleted. A short record of which plants an import added stays for 30 days.

Nothing goes in until you've looked at it

The screen that matters most is the one before anything is added. It's called "Check before adding", and it shows every row with what Fern made of it.

Each plant gets a species and a word for how sure Fern is: Sure, Probably, Not sure or No match. Fern's plant catalogue answers first. A name that is exactly a plant's, like "Monstera deliciosa" or "Snake plant", is Sure. Words that clearly point to a well-known plant, like "ZZ" or "Fiddle leaf", are Probably. Whatever's left goes to the AI in one go, and its answers are looked up in the catalogue again before you see them. Under each species the row shows what you actually wrote, so you can judge the guess against your own words.

One example taught us something. When we tried the import against the real AI, "the spiky one by the door" came back as a snake plant, marked Sure. It may well be one. But nobody should be sure of a plant from six words, so the rule changed: a plant read from someone's description is only as sure as the description. That line now shows as Not sure, and it's one tap to fix.

Fern also looks for plants you already have. A row with the same name as one of yours, or the same species in the same room when the match is confident, gets "Looks like Monty already in My Plants" and two choices, Merge or Add anyway. Merging never overwrites anything. It adds the watering date if the spreadsheet's is newer, fills in when you got the plant if Fern didn't know, and says so underneath: "Nothing of Monty's is replaced."

You can change any species, use "Add as unknown" for a plant you can't name yet, set the home and room for several rows at once, or skip a row. Then Fern adds the plants a few at a time, "Building each care schedule from its species."

This step is the slowest part of importing, and with 500 rows it's a long scroll. We could have added everything at once and let people tidy up afterwards. The reason to stop here is that in Fern, care starts from the species. A plant matched to the wrong one starts life with the wrong watering plan, and finding that out three weeks later from a drooping plant is much worse than a minute of checking.

Two more things happen when you add. Imported plants are private, whatever you've chosen for new plants in Growers, and the first screen says so: "Nothing is added until you check it, and imports never post anything to Growers." And when the plants land in a shared home, the others get a single notice for the lot, like "Ava added 41 plants to Flat 4B".

Then there's undo. For 24 hours after an import, Your data shows a card that says "You can undo until 9:41 tomorrow", with the real time. Undoing removes the plants it added and any waterings it merged into plants you already had. If you've marked care on the new plants since, the warning tells you how many times, because that care goes too.

What comes out

"Export your collection" starts by asking what to include. There are four parts, all switched on to begin with:

• Plants: names, species, home, room, dates and watering schedule, in plants.csv.
• Care history: "Every watering, feed and repot, with who and when", in care-history.csv.
• Photos: "Full size, in a ZIP", in photos.zip.
• Notes and measurements: "Heights, leaf counts, your notes", in notes.csv.

The format is plain CSV, described on screen in one line: "Opens in Numbers, Excel and Google Sheets. One file per section." Dates and times are in your own time zone, and heights are in centimetres or inches, whichever you use in Fern. The photos are every picture of your plants stored in Fern: each plant's main photo, its journal photos, growth photos and the photos from health checks, in a folder per plant and named by date, like "Monty/2026-03-12 journal 1.jpg".

Fern's server makes each file when you ask and hands it straight back. It doesn't keep a copy. Your phone fetches the photos itself, through links that work for six hours, which is long enough for a big export on a slow connection, and puts the ZIP together. Meanwhile you can carry on: "Keep using Fern. We'll let you know when it's ready."

If the connection drops halfway, the export doesn't throw away what it has. It says "Can't reach Fern." and explains that everything on the phone is ready, and some photos are only in Fern's cloud. You can export straight away without the missing photos, or choose "Finish when I'm back online" and let Fern complete the ZIP when it can. When it's done, the files open in the share sheet, and that's the first time they go anywhere. "Files stay on your phone until you choose where to send them."

Spreadsheets, and what they can't carry

The big decision was the format. We could have made a single Fern backup file that restores an account exactly, with every plant, every watering and every photo back in its place. We chose spreadsheets that open anywhere. A file you can only read with the app you're leaving isn't much of a way out.

The cost is that an export isn't a backup. plants.csv goes back into Fern the way it came out, so a fresh account gets its plants back with their names, species, rooms, dates, last waterings and notes, and Fern builds each schedule again from the species and that last watering. The care history, the notes file and the photos don't go back in. They're yours to keep, open and search, but Fern can't put them back into a plant's timeline.

We also had to decide whose plants an export holds. The answer is every plant you see in My Plants, and that includes plants other people added to a home you share. care-history.csv says who did each watering: "You" for you, and the person's name for everyone else. So an export of a shared home carries your housemates' names. We think that's right, because it's the same list you look at every day and the file only goes where you send it. It's still worth knowing before you post your care history somewhere public.

Some things aren't in the export at all. Plants you've marked as died live on as memorials under Remembered, outside your plant list, and the export leaves them out. Health checks put their photos in the ZIP, but not Fern's diagnosis. Plant family links, which plant came from which, aren't there, and neither are your Growers posts.

Leaving comes in different sizes

"Leaving" covers a lot of different moments, and each one keeps something different.

The smallest is stopping Pro. The FAQ answer is the one we'd give in person: "Pro stays on until the end of the period you've paid for; after that you move to the free plan and nothing is deleted." Five plants keep their reminders, and the others rest until you choose them again.

Then there's leaving a home. Fern has one rule for plants in a shared home: a plant belongs to whoever added it. So "Leave Flat 4B" has the subtitle "Your plants come with you", and they do. The plants you added leave the home and become just yours, history and all. If you were looking after someone else's plant there, you stop.

The owner can't leave their own home but can delete it, and the same rule holds: "Plants go back to whoever added them." When the owner removes someone, the confirmation reads "Their plants leave this home with them, and they stop getting its reminders." A single plant can leave a home on its own too, through Move and "Just me".

Leaving Growers is softer still. The "Leave Growers" row is subtitled "Hides your profile, posts and comments", and if you rejoin with the same handle, they come back. Hidden isn't gone, though. If you want a post gone for good, you delete it, and Fern is direct about what that means: "It comes down for everyone, with its comments."

Signing out leaves your account exactly as it is. Fern clears what it kept on the phone for offline use, like Today, your garden and the You tab, so the next person who signs in on that phone doesn't see it.

Deleting your account

The biggest exit is "Delete account", at the bottom of You, with the line "Hand your homes to a member first" under it.

That line is there because of shared homes. The screen opens with "Checking what you'd leave behind…" while Fern looks at your homes. If you own a home that other people live in, you pick who takes it over, and the delete button stays grey until you have: "Choose a new owner for every household first." Homes where you're the only person are closed. Homes you belong to but don't own, you simply leave. Everyone affected is told, and the new owner gets "Ava left Flat 4B. You're now the owner."

The last step is an alert titled "Delete your account forever?" that says "Your plants, care history, badges and settings are erased. This can't be undone." Pressing "Delete everything" removes your account and your plants, with their care history, notes and health checks, in one step. If you signed in with Apple, Fern also revokes its Sign in with Apple link.

What goes with you, and what stays

The rule from shared homes holds here too, and it has a cost we want to be plain about. Plants other people added to a home stay where they are. Plants you added go with you, and when the account is deleted, "with you" means they're deleted. If you added Monty to Flat 4B, Sam loses Monty. The same goes for care. A watering belongs to whoever did it, so the waterings you logged on Sam's plants leave their history when you go.

If you want a plant to stay behind with its story, the way to do that today is to give it away first. A gift code gives someone else on Fern a plant of their own, with the photos and care history you choose to send, and because it's theirs, it stays when your account goes.

Growers works the other way round. Your profile, follows, likes, blocks, saved posts, poll votes and stories are deleted with the account. Your posts and comments stay, with the author shown as "[deleted]" and a plain outline where your photo used to be.

That choice is about other people's words. A question you asked might have a handful of answers under it, written by people who took the time to look at your photo. Deleting the post would take their answers with it, which is exactly what happens when you delete a post yourself. Keeping it under "[deleted]" keeps those answers there for the next person with a crispy calathea, without your name on any of it.

Our plan for Growers said the delete screen should explain this and give you a chance to delete posts first. It doesn't do that yet. Today it talks about plants, care history, badges and settings, and doesn't mention posts at all. Until it does, if you want your posts gone, delete them before you delete your account.

One more thing outlives an account, and it's small. Fern keeps a record keyed to a one-way hash of your Apple or Google sign-in, and it holds three things: when your free trial ends, when you first came to Fern, and whether the account was banned. It exists so that someone who deletes their account and signs up again with the same sign-in picks up the trial where it was. It holds no name, no email and nothing about your plants. Still, deleting your account doesn't make Fern forget you completely, and we'd rather say that here than have someone find it out.

Guests

Fern lets you start without an account. A guest is a real account that can't be signed into, tied to an id the app keeps in the phone's Keychain, so it survives reinstalling. For a guest, the You tab opens with "Save your garden" and a sentence like "Your 3 plants only live on this phone. Save them so nothing is lost if you switch phones."

A guest doesn't see Delete account at all. There's no account to delete yet, and saving the garden comes first. Guests who never save and don't open Fern for 30 days are removed, with everything in them. And if you save with an Apple or Google sign-in that already has a Fern account, say because you reinstalled and started over, the guest's plants and their care history move into that account and the guest is deleted.

What we left out on purpose

The deliberate absences are mostly about Fern holding less. Fern doesn't keep your export: the files are made, handed to your phone, and that's the end of it on our side. It doesn't keep your spreadsheet beyond the day it takes to check and add it. And an import never touches Growers, whatever your settings say.

Other gaps are plain limits. Fern reads CSV and tab-separated files, not Excel or Numbers files, so a workbook has to be saved as CSV first. It doesn't connect to other plant apps; the screenshot is how a list gets from one of them into Fern. An export only happens when you ask for one. And as above, there's no full restore.

What we haven't settled

Shared history is the hardest one. Right now a watering belongs to the person who did it, so when someone deletes their account, the shared plants they looked after lose that part of their past. That follows the rule cleanly, and it can leave gaps in a plant's history that the people still caring for it didn't make. Should a person's care on a shared plant stay behind without their name, the way their Growers posts do? We don't have an answer yet.

Handing over a home only works on the way out. An owner who wants to give the home to someone else and keep using Fern can't do that today. The only handover is the one inside account deletion.

The delete screen doesn't point to Your data. That's the moment someone is most likely to want their files and least likely to think of them, and we suspect it should offer the export before anything else.

Guests can't delete. A guest who wants their garden gone today has to stop opening Fern for 30 days, or save it and then delete the account. Saving means signing in with Apple or Google, which leaves the small record described above. Neither is a good answer.

And an export isn't a restore. A file you can open anywhere was the right place to start, we think. But someone who deleted their account and comes back a year later would want their care history and photos to go back in too, along with the plants in Remembered.

If you're leaving today, this is the order we'd suggest: export first, give away the plants you want to stay with someone, delete the posts you want gone, and only then press "Delete everything". Every step in that list is one the app should eventually tell you about itself.