How long is a time capsule usually sealed for?

The three most common horizons are one year (for little ones, where it can become a yearly ritual), ten years and an 18th birthday. The longer the wait, the more it matters to keep the capsule somewhere dry inside the home and to leave a note about it with the family paperwork so nobody forgets it.

Can you bury a time capsule in the garden?

You can, but you'll need a waterproof container, a depth below the frost line, the spot measured from two fixed landmarks and confidence that the property will still be yours in ten years. A box in the wardrobe is safer for paper and photos; the ground suits objects that damp can't hurt.

What do you write in a letter to a baby who is only a few months old?

Describe the day, not your feelings. Where you live, what the room looks like, what time your baby falls asleep, what makes them laugh, the name of the lady next door. General wishes go stale; concrete everyday details are the one thing nobody will otherwise remember in eighteen years.

How many things should go in the capsule?

Three to five objects, five to ten printed photos and one letter on a single sheet. An overstuffed box is harder to close and to store, and when it's opened the important things get lost. If the box is half empty, pad it with clean paper so the contents don't slide around.

How do you stop someone opening the capsule early?

The most reliable way is a contents list and the opening date written on the outside of the lid — most early openings come from not knowing what's inside. A simple seal or a wrap of tape does the rest: the aim isn't a safe, just a small hurdle that makes people stop and think.

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Letter to the future and time capsule: what goes in, when

02/09/2026 · The Hero of the Book Team

A time capsule in one afternoon: what belongs inside, how to write a letter to the future and when to open it so it's still readable years later.

Letter to the future and time capsule: what goes in, when

Quick answer

A time capsule is a sealed box of everyday things from today that the family opens on a date agreed in advance, and a letter to the future is the most precious thing inside it. You can put one together in a single afternoon: a well-sealing box or tin, three to five objects that look completely ordinary right now, some printed photos and a handwritten page about what life in your home is like at the moment.

The one decision worth making right at the start is the opening date. Write it on the outside of the lid and put it in the family calendar, otherwise someone will open the capsule "just for a peek", or it will be forgotten in ten years' time.

A time capsule in one afternoon: step by step

The order isn't random. Most capsules that end up half-finished in a drawer fall apart at the stage where everyone gathers lovely objects and the letter gets put off until later.

1
Agree on the opening date
Before you collect anything, say out loud when the capsule will be opened: a specific year, ideally tied to an occasion (an 18th birthday, finishing school, ten years from today). The date shapes everything else, above all how carefully the capsule needs to be stored.
2
Choose a container to suit where it will sit
For a wardrobe, a sturdy box with a lid or a biscuit tin is enough. A cellar, garage or the ground calls for a container that genuinely seals, because damp is a bigger danger to paper and photos than time. Pick a container two fingers wider than the largest sheet of paper going in: nothing should have to be folded to fit.
3
Write the letter first
The letter is the one thing nobody else can write. Give it twenty minutes and a single sheet, not a half-filled notebook.
4
Add three to five everyday objects
Not the nicest things you own, but the most ordinary: a bus ticket, a shopping receipt, a drawing made that day, a stub from a cinema programme. In ten years it's exactly this everyday material that will be interesting, not a souvenir chosen for the occasion.
5
Print photos and note who and when on each
Photos on your phone won't make it into the capsule. Print five to ten shots and write the name, place and date on the back in soft pencil. Without captions, half the people in the photos will be unrecognisable in fifteen years, even to your own family.
6
Write a contents list and stick it on the outside
Two things belong on the lid: the opening date and a short list of what's inside. The list stops anyone opening the capsule early simply because they can't remember whether there are important documents in it.
7
Seal it and tell one more person about it
A capsule that only one person knows about goes missing at the first house move. Tell your partner, a sibling or a grandparent, and add a note to the family paperwork.

A letter to the future: paragraphs to copy

The first sentence is the hardest. The paragraphs below are there to copy and fill in; replace the brackets with your own words. The best letters aren't wise, they're specific: the price of a bread roll, the babysitter's name, the sentence your child kept repeating that week.

From a parent for an 18th birthday

"I'm writing to you in (month and year) and you are (age). This morning you (what they were doing) and you said to me: (something your child really said). I don't know who you are now, but I know what it was like to have you at home this year — and I wanted you to know it too."

To a baby who will read it years from now

"As you read this, you're as old as I couldn't even imagine today. We live at (address), you sleep in a room with (description), and you fall asleep best when we sing you (song). Your day looks like this: (three sentences about an ordinary day)."

To yourself in ten years

"Right now I'm busy with (one worry) and I think that in ten years (prediction). When you read this, check whether it came true. What I want most today is (wish), and what I'm afraid of is (fear)."

From a grandparent to a grandchild

"At your age I (what I did, where I lived). Things you take for granted today weren't in our home: (two specific things). I want you to know one family story that nobody else will tell you: (a story in five sentences)."

A final paragraph to finish on

"I don't know what has happened between today and the moment you read this. But this day, (date), was ordinary and it was good. Signed: (name), (date)."

What belongs in the capsule and what will ruin it

Papers that look worthless today
A receipt with prices, a ticket, a flyer from an after-school activity, a class timetable, a printed order. These are exactly what gets read most years later, because nobody keeps them. Receipts on thermal paper fade to blank within a few years, though, so photograph them or copy the amount onto the margin in pencil.
A hand outline, a height, a dated drawing
A hand traced on paper weighs nothing, and after ten years it's the most convincing proof of how small your child was. A longer-lasting option is a hand or footprint, but it deserves its own wrapping so it doesn't rub against the papers in the box.
Printed photos, not just files
A printed photo is the one thing in the capsule you don't need any device to open. Keep photos in their own envelope rather than loose among the papers, ideally in a sleeve labelled acid-free.
Sound, if you can store it twice
A recording of your child's voice or a story read aloud is the most powerful thing in the capsule, and also the most fragile. It belongs in the box only as an extra copy; the main copy has to stay outside on a drive that gets used regularly.
Nothing that can leak, rot or swell
Lollies, seeds, perfume, balloons, rubber toys, batteries. Rubber and balloons break down into a sticky mess, and batteries leak and corrode everything around them. A flower can only go in if it's dried and layered between sheets of clean paper.
Newspaper and sticky tape
A newspaper from the day of birth is a lovely idea, but acidic newsprint yellows and transfers onto everything it sits against. Put it in a separate envelope. Never repair photos or documents with sticky tape; the adhesive seeps through over the years.
The only copy of anything
The capsule is no place for the only existing print of a photo, the only original of a document or a USB stick holding the only copy of a video. A time capsule is a gift, not an archive.

When to open the capsule: four dates and what suits each

Opening date	Who it suits	What to add	Watch out for
In a year, on the next birthday	A preschooler, for whom a year is forever	A height chart, a drawing, a photo taken from the same spot and the same angle	A short gap means a small change. Make it a series and add to the capsule every year.
In ten years	A school-age child who will open it as a teenager	A list of friends, favourite songs, prices of everyday things, a copy of the weekly timetable	It has to survive a house move too. Label the box on the outside and add a note about it to the family paperwork.
On the 18th birthday	A newborn, and a letter from the parents	The hospital birth bracelet, a separate letter from each parent, a newspaper from the date of birth	The longest wait makes the toughest demands on storage. Give the newspaper its own envelope.
At a wedding or the birth of their own child	Grown-up children, with grandparents as the writers	A family recipe, a photo of the house, a letter about what life was like before the children came	The date isn't certain and may never come. Write a fallback date on the lid too, say a 30th birthday.

Where to store the capsule so it's still readable years later

The enemy isn't time but damp and swings in temperature. The US National Archives recommends keeping family papers and photos below 24 °C and below 65 % relative humidity, because mould grows above that level, while also avoiding very dry conditions under 15 % humidity, where paper turns brittle. A damp cellar, the garage and a baking-hot attic are therefore the three worst places, even though they're the ones people pick most often.

A good spot is inside the home: the top shelf of a wardrobe, the space under a bed, a storage cupboard. Put the box on a shelf rather than straight on the floor, and away from pipes, windows and anywhere that has leaked before. Inside, use acid-free, low-lignin sleeves and folders, and don't bend anything to make it fit. If the box is half empty, pad it with clean paper so the contents don't slide back and forth.

Burying it in the garden is possible, but it's a different discipline: you need a truly waterproof container, a depth below the frost line, the exact spot carefully mapped and confidence that the property will still be yours in ten years. For most families a box in the wardrobe does the job better.

And one last thing people forget: what you write with. An ordinary soft pencil and pigment ink last; gel pens, highlighters and stamp-pad ink fade. Always write on the back of photos in pencil, and only lightly. Handle photos and negatives with gloves, or at least by the edges, because fingerprints stay on them for good.

A digital letter to the future: an email that arrives on its own

There are services that send an email to yourself or someone else on a set date in the future; the best known is FutureMe. Writing such a letter takes ten minutes and costs nothing. But it has two weak points to keep in mind: the inbox it's addressed to has to survive (an address from an employer or an internet provider won't), and the service itself has to survive. For a five-year horizon it's a nice idea; for eighteen years, paper is more reliable.

The digital part of the capsule deserves the same rule that both the National Archives and the Library of Congress recommend for family archives: three copies, on two different types of media, one kept outside the home. A USB stick shut in a box doesn't meet a single part of that rule, because it's one copy on one medium in one place. Whatever digital items you add to the capsule, keep the main copy outside it, in a folder you use and back up regularly, and name the files so they make sense without you: date, name, occasion.

What keeps being read after the capsule is opened

A capsule is opened once. Much of what's inside is used up at that moment: the ticket gets read, the family has a laugh about it and it goes in the bin. But a few things survive the opening and the family keeps coming back to them. These are the ones worth choosing when you want the capsule to be a gift, not just a moment.

Three work best: the letter (read again and again, especially by children whose letter was written by someone who is no longer here), printed photos with captions and something engraved with a date, such as jewellery with a name and date or another keepsake gift that can be worn or set on a shelf.

A fourth option is a book. A personalised book with your child as the hero has a blank page at the front for a dedication, and that is a letter to the future with a cover and a spine: your child will read it on their own once they can read, and the book stays with them on the shelf instead of in a box. You can write the dedication in one evening, the digital book is usually ready within 15 minutes and the story has 12 illustrated spreads. If you're unsure about the wording, common mistakes and texts to copy are in our article on what to write in a dedication; either way the same rule applies as for the letter in the capsule — a specific date and one real memory beat a general wish.

Sources

National Archives (USA): Storing Family Papers and Photographs — Recommended storage conditions for family papers and photos — temperature, relative humidity, acid-free enclosures and why to avoid the cellar, garage and attic.
National Archives (USA): Digitizing Family Papers and Photographs — The rule of three copies on two media with one kept off-site, naming files and why to keep the originals even after scanning.
Library of Congress: Personal Digital Archiving — How to look after digital photos, emails and recordings so they can still be opened years later.
FutureMe — A service that emails your future self on a chosen date; an example of what the digital version of the letter looks like.