Why Fern has a community, and why it starts with plants

Picture a calathea on a bookshelf. Its leaf edges have started going brown and crisp, and its owner opens Fern to find out why. Fern looks at the photo and the plant's history and suggests the air is too dry. It might be right. It might also be the water, or a cold draught from the window, or the plant still settling in after the move from the shop.

At that point, what most people want isn't another explanation. They want someone who grows calatheas in a home like theirs to look at the photo and say "mine did exactly that, here's what helped". So they leave the app. They post in a forum or a group chat, wait, get six contradictory answers, and the conversation ends up somewhere that knows nothing about the plant.

Growers, the community inside Fern, exists for that moment and a few like it. This post is about why we built it, what we were worried about, and the decisions that came out of those worries.

What a care app can't do alone

Fern started as a private tool, and most of it still is. You add your plants, Fern works out when each one needs water or food, and everyone in your home sees the same plan. All of that works without strangers.

But a care app only knows averages. It knows what a monstera generally wants, and it learns how your monstera drinks. It can't show you what a monstera looks like after two winters in a north-facing flat, or how big a pothos gets in a bathroom with no window. Those answers live in other people's homes.

When we wrote down what the community was for, the list was short:

1. Show real examples of a species growing in different homes, light and seasons.
2. Give people a second opinion when Fern's guidance is uncertain.
3. Let people celebrate progress, like a new leaf or a rescued plant, without turning it into a competition.
4. Help people find growers they trust and come back to see how their plants are doing.

The same document had one line about what it shouldn't be: a generic social network placed inside a care app. Most of the decisions below come from taking that line seriously.

What worried us

Adding a social feed to an app like Fern is risky in a few specific ways.

The first is privacy. Plant photos are taken inside people's homes. A shelf by a window can say a lot about where someone lives. And Fern already holds private things: which plants are struggling, who you live with, when you're away on holiday. A community that leaked any of that, even by accident, would undo the trust the rest of the app depends on.

The second is tone. We've written elsewhere about keeping Fern calm. Social apps usually run on the opposite energy: counts going up, notifications pulling you back, a quiet sense of being compared. We didn't want someone with three plants to scroll past a stranger's jungle and feel bad about their own.

The third is safety. Any space where strangers can post needs reporting, blocking and moderation, and those are much harder to add after people have already arrived.

Your home is not the community

Fern already had a place where things are shared: your household. The people you live with see your plants, and when Sam waters Monty, everyone in the home can see it happened. That sharing is automatic, because coordinating care is the whole point.

The easy move would have been to let some of that flow outward, so a care milestone or a new plant posted itself to your profile. Feeds built that way fill up quickly, and a full feed looks alive.

We went the other way. Nothing reaches the community on its own. Not a plant, not a watering, not a diagnosis. When you share something, you see a preview first and confirm it. What goes out is the photo you picked and the species. The plant's nickname, its room, its care history, its diagnosis and the hidden location data inside the photo file all stay behind.

This makes the community quieter than it could be. A feed made only of things people chose to post grows more slowly. We decided that was the right price, because the alternative is a feed where nobody is quite sure what they've shared.

Sharing one plant at a time

Most apps ask you once whether your account is public. Fern asks per plant, because that's closer to how people feel. You might be happy to show the monstera you've had for five years and less keen to show the fiddle-leaf fig you're slowly nursing back from root rot.

Each plant has its own audience: just you, your household, your followers, or everyone. Before a plant becomes visible to anyone new, Fern shows exactly what will be shown and what never will be. If the plant lives in a shared home, the preview says who already sees it, in words like "Sam and Leo in Flat 4B will see…", so nobody is surprised.

New plants start private. You can choose a default for future plants, but even then, a plant only becomes visible once its name and photo have passed a check.

There's one rule that took us a while to see. Notes and updates can be attached to a plant, and a note could be set to "everyone" on a plant that only your followers can see. That note would point to a page most people can't open. So a note's audience can never be wider than its plant's. It's a small thing, and it's the kind of small thing that decides whether people trust a sharing model or quietly stop using it.

A profile that starts with the garden

On most social apps a profile is a scoreboard. Followers, following, likes, posts, all in large numbers at the top.

A Fern profile opens with plants. First what this person grows, then the plants they've shared, then their posts and notes. Counts exist, as one small line in the header, and they're never the first thing you see.

We also wanted a way to recognise people who help without creating a ranking. The answer is what we call a quiet reputation. When someone's answers are marked helpful, their profile says so in a sentence, something like "12 Helpful answers · Helpful on Pilea, Pothos". There is no score and no level, and Fern doesn't compare care streaks between people. The one place growers appear in an order is the Growers map, where each area's "Top growers" puts people with Helpful answers first, then people who post, so the people worth asking are easy to find.

Location without addresses

Location matters for plants. Advice from someone in a humid coastal city may be useless in a dry inland one. So the community needs to know roughly where people grow, and it must never reveal where anyone lives.

On a profile, the place is something you type yourself, like a city name. Fern never shows coordinates. The season attached to a post is worked out from its date and your hemisphere, and your hemisphere isn't shared with it.

The Growers map shows where growers are, and it was the part we were most careful with. It shows areas, never people. A grower belongs to their country, region, city and, only if they choose, their district. An area appears on the map only when at least three growers are in it. Smaller areas fold into their parent, so you'll see "Elsewhere in Casablanca" rather than a dot over two people's flats. Where an area is drawn comes from rough cells about six kilometres across, so the map never holds anyone's actual spot. People who have blocked each other don't exist on each other's map at all, not in the counts and not in the lists.

A feed that doesn't reward the already popular

The usual way to rank a feed is by engagement. Posts with lots of likes go up, so they get more likes, so they go further up. It works for keeping people scrolling. It's also a reliable way to show the same few beautiful jungles over and over, while the question someone posted at 11pm about a dying calathea sinks without an answer. That question is often the most useful post of the day.

The For You feed starts from what you grow and the climate you grow in. A few rules shape what reaches you.

New posts get a fair start. A post is first shown to a small group of people it suits, 30 of them, then 60, then 90, before it can go further. Three cheap chances mean one unlucky first batch doesn't decide a post's fate, and a big following doesn't let anyone skip the queue.

Questions are routed to people who can answer them. A question about a pilea is lifted for people who grow pileas, more so while it has few answers, and unanswered questions stay fresh for longer than other posts. About one card in four is a question.

No single person fills your feed. In any stretch of 20 cards, the same person never appears twice in a row, and nobody gets more than two cards. One species gets at most four.

And the reason a card is shown is always about you, never about numbers. It might say "You grow Pilea" or "Popular in Mediterranean climates". It never says how many likes something got.

If you'd rather just see the people you follow, the Following feed is simply their posts, newest first.

Questions are the heart of it

If we had to keep one part of Growers, it would be questions.

Fern's diagnosis tries to be honest about uncertainty. When it isn't sure what's wrong with a plant, it offers to ask the community, and that's the only time it does. The draft question it creates has the photo and the likely species. It leaves out Fern's diagnosis, its confidence and the plant's private details, unless you choose to type them into the question yourself. That way people answer from what they see in the photo, not from Fern's guess.

When an answer helps, the person who asked can mark it Helpful. That's a thank-you from the asker. It isn't Fern vouching that the advice is correct, and the app says so: community answers are other growers' experience, not professional advice. Fern's own uncertainty and safety notes still show where they apply.

The ways to share

Growers started with two kinds of post: a showcase for a new leaf, a cutting or a setup, and a question. It has grown since. You can post words without a photo, add notes to a plant's page, share a story that disappears after a day, and run a poll or a quiz. Comments can have replies, one level deep, and a photo of their own.

Each format went through the same questions. Who can see it? Can it reveal anything private? Can it be reported? Stories are a good example. A story photo goes through the same check as a post, and a reply to a story is only ever seen by the story's author, so if a reply can't be checked in time, it's quietly held back rather than published.

Safety came first

Reporting, blocking and moderation weren't follow-up work. The plan said the community couldn't launch until they worked end to end, and that held.

Every post and comment is checked automatically when it's published. Sometimes the check can't run, because a service is down or slow. When that happens the post waits, gets checked again shortly after, and is either published or sent to a person. After a day of failed checks, a person reviews it anyway. Nothing waits forever.

Every post, comment and profile can be reported, and reports are private: the person reported isn't told who reported them. Moderators hear about reports straight away, and every action they take is recorded. Blocking is complete. Two people who have blocked each other can't see each other's profiles or posts, can't follow or reply, and vanish from each other's map.

There are limits on how fast anyone can act, to slow down spam and pile-ons: 30 likes a minute, 6 comments a minute, 20 follows a minute and 5 new posts an hour, among others. And you choose who can comment on your posts: everyone, people you follow, or nobody. You can set a default and change it per post.

Who can take part

To join Growers you need a saved account. Fern lets you start as a guest, without signing up, but a guest has to save their garden before joining. A community where nobody can be held to anything doesn't stay pleasant for long.

Reading is free for everyone with an account. Posting, commenting, liking and following are part of Fern Pro. That keeps the community smaller than it could be, and it means some people with good answers can read a question but not reply to it. It's one of the decisions we're watching most closely.

What we left out

Some things were left out of the first version on purpose. Private profiles with follow requests are a reasonable thing to want, and they change who can see what in ways that touch every part of the sharing model, so we'd rather build them carefully than quickly. Posts are visible to signed-in Fern members only, not to search engines or people without the app. That makes Growers harder to discover from the outside, and it's much easier to open a space up later than to make it safer after the fact.

Other things are left out for good. There will be no global leaderboard, no comparing streaks between people, and nothing posted on your behalf.

What we haven't settled

A few questions are still open, and we'd rather say so than pretend otherwise.

How much location is right? A city helps people judge whether advice fits their climate. A climate label alone is safer. Right now you choose what to type, and the map never goes below the areas described above, but we keep coming back to whether a city on a profile is too much.

Should taking part stay in Fern Pro? It keeps spam down and the community small. It also keeps out people who'd answer questions well.

How do we keep questions answered as the community grows? Routing questions to people who grow the plant works when there are enough of them. In a small community, a question about a rare plant may still wait too long, and we haven't solved that yet.

Those are the things we'll be watching. If you use Growers and have a view on any of them, we'd like to hear it.