One home, many hands

Picture Flat 4B on a Sunday. Monty, a monstera, lives by the living room window. Ava waters him in the morning before she goes out. Sam gets home in the evening, sees "Water Monty" on his own phone, and waters him again. The next week it goes the other way: each of them assumes the other one did it, and Monty waits ten days.

Neither of them did anything wrong. They were using reminders built for one person, in a home with two.

That's the gap households in Fern are meant to close. This post is about the decisions behind them: who hears about a plant, how everyone knows what's been done, what happens when someone goes away, who sees what, and the parts we haven't worked out yet.

A reminder for nobody in particular

Most plant apps are personal. A reminder says "Water Monty", and it's addressed to whoever installed the app. When one person looks after the plants, that's fine. When two or three people do, the same two words turn into a question: water Monty, but who?

The two simple answers both fail. If everyone gets every reminder, plants get watered twice, and the second person to act is the one who overwaters. If only the person who added a plant gets its reminders, everyone else is in the dark, and the plant depends on one person's week going to plan.

Our experience spec has a short list of how people should feel after using Fern. Two lines on it are about exactly this: "Less likely to double-water" and "More comfortable asking someone else for help". One of Fern's six product principles is "Shared, not complicated", with one sentence under it: care should be easy to coordinate.

The second half of that principle is the hard part. Sharing can easily turn into a chore chart, with rotas and permissions to manage. It can also make the noise worse, since every extra person is another source of news. Most of what follows is about answering "who?" without either of those.

One home, one set of plants

A home in Fern is a shared garden, like a flat or an office. Everyone in it sees every plant in it, with one schedule and one history per plant. When Sam opens Today, the header says "Flat 4B · shared with Ava", and each task says whose it is, "Yours" or "Ava's". If you don't share a home with anyone, Today never labels a plant, because the answer is always you.

Underneath that are a couple of plain rules. A plant belongs to whoever added it, and it lives in one home at most. Joining a home doesn't pull your plants into it; until someone moves some in, the home's page says "No plants here yet. Move plants into Flat 4B from My Plants."

The alternative is to give each person their own copy of the schedule and keep the copies in step. Each Today would stay shorter. But it means two schedules for one pot of soil, which is how Monty got watered twice in the first place. With one schedule per plant, one watering marks the task done for the whole home.

The cost is a busier Today. Sam sees Ava's plants under "Needs you today" as well as his own, each with a name on it, ranked by how much they need care, whoever they belong to. In a flat with eight plants that's helpful, because anyone can see what's left and step in. In a home with a hundred, other people's plants can push yours down the list.

Everyone, until someone says it's theirs

The rule for reminders is the centre of all this, and it fits in four sentences. A plant in a shared home either has a caretaker or it doesn't. Without one, everyone in the home hears about it. With one, only the caretaker does. If the caretaker is away, it goes back to everyone.

The home's plant list says it in one line: "Everyone sees their reminders until someone claims them."

The obvious alternative is to assign every plant up front, like a chore chart. That looks tidy on day one. By week three the chart is out of date, and a plant assigned to someone who has stopped paying attention is worse off than one the whole home can see. Starting from "everyone" means nothing needs setting up before it's safe. A plant nobody has claimed is already covered.

Claiming takes one tap. On Today, a shared task nobody has claimed says so, in a line like "Flat 4B · no one yet", and it has a single button: "I'll take it". Done and postpone only appear once it's yours. The home's plant list has the same button, and a "No caretaker yet" filter for the plants still waiting.

Anyone in the home can also give a plant to someone else, and that's never silent. From that moment the plant's reminders go to that person alone, so they get a notification titled "You're the caretaker now", and the rest of the home sees a line in its activity.

This rule has two costs. A home that never claims anything is back to Monty's first problem, two reminders for one plant, and what protects him then is the next section. And claiming lasts. "I'll take it" makes you the plant's caretaker from then on, until someone changes it.

Seeing what's already done

If two people can both be told to water Monty, the next best thing to only one of them being told is both of them seeing when it's done.

On Today, care someone else did stays on the list, faded, with "Done by Sam" where the due time used to be. When everything for the day is finished, the "All done" card gives credit in its summary line, something like "5 care actions · Sam did 2".

Each home's page has a Recent activity section, and a full Activity screen behind it, subtitled "Care, moves and who took what". It's a short diary built from the care log and the record of moves and caretaker changes: who watered what, who moved a plant to another room, who claimed, gave or let go of one. There's nothing to post to it.

Care rounds use the same idea on a scale of minutes. When two people go round the flat at once, a plant someone is looking at shows "Sam is checking", and if you get to it anyway, Fern asks before you take over. The claim expires after two minutes unless that person's round keeps renewing it. A hard lock would be stricter, but a lock left behind by a phone in someone's pocket would block the other person for no reason.

The home's page also has a "This week" summary, and behind it a screen called "How the home is doing". It shows each person's share of the month's care as a percentage, how the plants in each place are doing, and a list of gaps, such as places nobody has watered for a week. The care split is the part of households we're least sure about, and we'll come back to it.

One small rule matters more than it looks. Fern sends a gentle "How are your plants doing?" to people whose plants haven't been cared for in two weeks. Care by anyone counts, so if Sam has been doing all the watering, Ava isn't told her plants miss her.

News without the buzzing

We wrote about the notification budget in Calm by design, so briefly: when someone you live with waters four plants in a row, you get one push, about ten minutes later.

A few details only matter in homes. Each piece of news lands in your Inbox straight away, as a line like "Sam watered Monty". Only the push waits to be combined, under the title "Plant care update". That push counts once toward the three care notifications Fern allows itself a day, the same budget the morning summary and evening nudge use. If the day's budget is already spent, the push is dropped and the news stays in the Inbox.

There are two switches, at two levels. "Household updates", in notification settings, turns off news about what others did, in every home. "Notifications from this home", in a home's own settings, turns off everything that home sends you, care reminders included. The second one is blunt. It's handy for someone in several homes who wants to step back from one without leaving it. It also means that if everyone in a home switched it off, Monty's reminders would reach nobody.

When someone goes away

People go away, and plants stay where they are. This is where a shared home helps most, and where the design has the most moving parts.

"I'm away" works on every plan. It pauses the plants you look after: no reminders, and nothing goes late while you're gone. Care that comes due waits as today's care, so you come back to today's list with nothing marked late. Say Sam is the one going. His Today says "Care is paused. Fern won't remind you, and nothing will count as late while you're gone."

In a shared home, someone at home still hears about each shared plant. Nothing goes late on a plant while everyone responsible for it, its owner and its caretaker if it has one, is away. Sam's away screen says "Your plants are paused. Shared plants with someone at home keep going for them.", and his Today names who, in a line like "Ava gets reminders for the 6 shared plants while you're away."

On Ava's side, the home's page shows a card when someone is away and has plants nobody is covering: "Sam is away until Sun 4 Oct", then "6 plants need someone while they're gone.", with two buttons, "Hand off 6 plants" and "Cover them myself". Sam's plants aren't abandoned without it, since an away caretaker's reminders already go back to everyone in the home. The card turns "everyone" into one person, for a set stretch of time.

Covering them yourself is one tap. It makes a handoff to you that starts now and ends when Sam is due back, or in a week if he didn't give a date. The home's page then says "You're covering Sam's 6 plants", and on Today each of those tasks carries "Covering for Sam".

Handing off to someone else opens a short form: who, from when until when, and which plants. It starts with you selected, the dates matching Sam's away mode, and every plant the card counted. People who've been invited but haven't joined yet can't be picked. Under the button, one line says what will happen: "Sam's reminders come to you until 4 Oct, then go back automatically."

That last word hides most of the rules. Fern remembers who looked after each plant before the handoff. When it ends, each plant goes back to that person, unless someone gave it to somebody else by hand in the meantime, in which case Fern leaves it be. If the earlier caretaker has left the home since, the plant goes back to nobody, which in a home means everyone. A handoff set for later starts on its own; Fern checks every five minutes. If a plant changed hands between the review and the start, that plant is skipped and the rest still go.

When Sam comes back, Today has a card for him for three days: "Welcome back, Sam", with a line like "Ava looked after 4 plants while you were away. 8 things are waiting." While he was gone he didn't get the household's news at all, because away mode stops it. The card is the summary instead.

The cost here is two ideas where people might expect one. "I'm away" is about you: your reminders, and whether your plants can go late. A handoff is about the plants: who answers for them between two dates. They're connected, since a handoff's dates start from the away dates and the away screen offers "Hand off to someone instead". But they're separate, and coming back early with "I'm back" doesn't end a handoff. It runs to its own end date unless someone ends it.

Inviting and joining

Every home has a code of eight capital letters and digits. The person joining types it into "Join a home", which says what it means: "Enter the code someone shared with you. You'll share their plants and reminders." The invite screen shows the code in large type, with Copy and Share link buttons; sharing sends a short message with the code and where to type it. There's no link that opens the app straight into the home, so the code always has to be typed. Anyone in the home with Fern Pro can invite people, not only the owner.

You can also invite someone by email, and that doesn't send an email. If the address belongs to someone on Fern, they get a notification and the invite waits in their app. If it doesn't, the invite waits seven days for whoever signs up with that address. The reply looks the same either way, so nobody can use the form to find out whether an address has an account. Apart from the owner and whoever sent it, people in the home see the address shortened to its first letter and its domain.

The owner can close the door. "New members can join with the code" is a switch in the home's settings, and when it's off, "The code won't work until you turn this back on." Removing someone also changes the code, so the one they knew stops letting them back in. Leaving on your own doesn't change it.

Joining can earn a week of Fern Pro for both people, and here there's a small mess to own up to. The reward only applies when the person joining is new to Fern: an account less than two weeks old, not one made again after deleting an old one. Each new member brings one reward, one person can earn three at most, and with a code the reward goes to the home's owner, because the code is theirs. The share message gets this right with "New to Fern? We both get more days of Fern Pro." The line at the top of the invite screen, "You both get 7 more days of Pro.", promises more than the rule gives.

Who sees what

Inside a home the answer is short: everyone sees every plant in it, with all of its care and history. That's what a home is for.

Around the home, the rules keep each side out of the other's business. A plant that isn't in the home doesn't exist as far as the home is concerned, down to its name. Names on screen are never email addresses, and someone who never set a name appears as "A housemate". When a shared plant dies, the home gets a gentle message, "Ava said goodbye to Monty.", and the cause isn't in it.

Some choices belong to each person. Pausing notifications for one plant is yours alone, and the people you live with still hear about it. The two switches above are personal too. Others belong to the plant's owner. Only the person who added a plant can delete it, move it to another home, or change who can see it on Growers, and the app keeps "Mark as died" for them as well. Anyone in the home can move it to another place in the home.

Growers, the community, sits on the other side of a firm line, which we wrote about in Why Fern has a community. The rule that matters here is that a plant in a home is always seen by its home. You can share it more widely, but you can't make it more private than the home it lives in. If you try, Fern explains: "Monty lives in Flat 4B, so the people there see it. Take it out of the home to keep it to yourself."

Leaving, and where the plants go

Flatmates move out. When someone leaves a home, what happens to the plants comes down to the rule from earlier: a plant belongs to whoever added it.

If you leave, "Your plants come with you." They leave the home with you, and you stop being the caretaker of anything that stays. If the owner removes someone, the same happens to them: "Their plants leave this home with them, and they stop getting its reminders." If the owner deletes the home, "Plants go back to whoever added them. Everyone else stops getting this home's reminders." Either way, a plant that leaves a home leaves behind its place there and any caretaker who isn't its owner.

The cost of that rule is easiest to see with Monty. Say Ava added him and Sam has watered him every week for a year. If Ava moves out, Monty goes with her. Fern doesn't weigh who did the caring, and the record of Sam's care is part of Monty's history, so it leaves too.

The owner is the one person who can't leave. They can rename the home, remove people or delete it, and the settings say so in a footnote: "Only you, the owner, can rename, remove people or delete." There's no way to pass a home to someone else, except when the owner deletes their Fern account. Then they choose a member to take it over, and if they don't, the home is closed. Deleting an account also deletes the plants that person added, including ones in a shared home.

What's free and what's Pro

The line between free and Pro falls between caring and sharing. A comment in the code for handoffs puts it plainly: covering plants yourself "is caring, so it works on every plan; handing them to someone else is part of Fern Pro."

On the free plan you can be in a home, look after every plant in it, claim plants, cover someone yourself, and use "I'm away". Starting a home, inviting people, handing plants to someone else and changing a handoff's dates are part of Fern Pro. A free member of a home sees a banner that says it in two sentences: "You can care for every plant here. Inviting, handing off and new homes come with Fern Pro."

The free plan keeps five plants active, and that limit counts the plants you added, never the ones you look after for someone else. A free member can look after a home full of other people's plants without reaching it. The cost runs the other way. If the person who added most of a home's plants is on the free plan, everything beyond their five rests, and a resting plant gets no tasks or reminders for anyone. And two people on the free plan can't start sharing at all: one of them needs Pro to create the home, though the other can join for free.

What isn't there

A few things are missing, and it's fair to name them. There are two roles, owner and member, with no admins, no members who can only look, and no permissions per plant beyond "whoever added it". There are no rotas: Fern doesn't take turns for you or split plants evenly. A plant is somebody's because they said so, and everybody's until then.

A plant lives in one home at a time. A cutting on your desk at work can be in the office while its parent stays in the flat, but one pot can't be in both. And there's no chat. A home has an activity log and no messages, and you talk to the people you live with the way you already do.

What we haven't settled

The care split is the part we're least sure of. A percentage next to each name helps when you want to know whether one person has quietly been doing everything. It's also a number about people, in an app that avoids ranking them anywhere else, and a monthly share can read like a score. For now it sits one screen down on the home's page, behind a link called "Care split, health by place, gaps", and on your own stats as a line like "You did 60% of Flat 4B's care this month".

Weather alerts don't follow the reminder rule. A frost warning goes to the plant's caretaker, or to whoever added it if there isn't one, while care reminders for a plant nobody has claimed go to everyone. Telling one person is calmer. On a shared balcony, though, the person who gets the warning might not be the one at home.

Should coming back end a handoff? Right now, if Sam comes home two days early, his plants' reminders keep going to Ava until the handoff's end date, or until someone ends it. Ending it automatically would be tidier, and it would also surprise someone who had planned their week around the dates.

Taking a plant on is either for good or tied to someone's trip. "I'll take it" lasts until someone changes it, and the only dated way to take plants on is a handoff, which is built around a person being away. A lighter claim, for this week only, would make it easier to step in, at the cost of one more idea in an app that tries to have few.

And the owner can't leave without closing the home. If the person who set up Flat 4B moves out first, everyone else has to start a new home and move their plants into it. Letting an owner pass the home on is the obvious answer, and today it only exists inside deleting an account.