How to keep bugs out of pressed flower frames

Nobody wants to think about bugs in their pressed flower art.

If you frame pressed flowers, especially if you sell them, this is one of those topics worth facing head-on.

Pressed flowers are dead plant material. And a handful of common household insects eat exactly that kind of thing.

Unless you work in a tightly controlled, climate-managed environment, you cannot remove the risk of bugs completely.

What you can do is lower it. A lot.

This post is what I actually do in my own home studio, alongside what the museum and conservation world has learned from keeping dried plant collections intact for decades. I press in a normal house, not a tightly-controlled studio environment, so everything here is built for real conditions.

None of it is a guarantee, but it will help stack the odds in your favor.

A few small household beetles and their larvae are the real culprits.

They feed on dried plant and animal matter: things like wool, dried food in your pantry, dead insects, and yes, dried and pressed flowers. In almost every case, it is the larvae doing the eating, not the adult beetle.

Here is the detail that tells you how real this is.

Entomologists nicknamed one of these beetles the "herbarium beetle" because of how reliably it turns up in dried plant collections. Museums that store pressed specimens have fought these insects for as long as they have kept the collections.

The other thing worth knowing is the hardest part to accept:

The eggs are essentially invisible, and they can ride in on the flowers themselves.

A bug or its eggs can arrive tucked inside a dried bouquet or a bundle of foraged stems long before you ever sit down to make anything. You would never see them.

That is exactly why prevention has to start before the flower goes anywhere near a frame.

It would be lovely if sealing a frame settled the whole question. Unfortunately, it does not.

These beetles can chew through paper, cardboard, and even thin materials to reach food.

Sealing a frame is genuinely worth doing. It keeps out dust, slows moisture, and puts a real barrier in a determined insect's way.

But no seal you can build at a kitchen table is truly bug-proof.

You should still seal your frames, but the work you do before sealing matters more than the seal itself. If the flower goes into the frame already clean and treated, the seal becomes a second line of defense instead of your only one.

Two things reliably kill insects at every life stage, including eggs: enough heat, or enough cold for long enough.

Both are used in professional conservation. Both are doable at home, with some honest caveats.

For most of these household pests, the lethal zone sits around 122 to 131°F (50 to 55°C).

Get the material meaningfully above that and hold it there, and you kill what is present.

My own method runs at 150°F (66°C), which clears that threshold comfortably.

One honest note: museum conservators actually caution against oven-heating delicate specimens too aggressively, because high heat can damage the internal structure of petals over time.

So I treat 150°F (66°C) as my own tested practice, not a rule I am handing you as gospel. Watch your flowers, and pull back if they show any sign of scorching or curling.

Freezing is the method museums lean on most, and it works, with a catch that matters at home.

The conservation standard is roughly 72 hours at around -22°F (-30°C), or about two weeks in an ordinary home freezer.

Freezing it for a few days or a week may not be enough, and here's why:

The fix is not complicated. If you freeze, give it the full two weeks, keep the freezer as cold as it goes, and do not count on a quick three-day chill to do a two-week job.

Here is my actual routine. It leans on heat, because that is what has worked for me.

My thinking is simple: heat kills the kinds of bugs and eggs that are likely to hitchhike, and doing it twice covers both the storage stage and the final framing stage.

Then there are the frames themselves. I have made two deliberate changes to what I offer:

Once a frame is tightly secured, I glue paper to the back to keep most bugs from finding their way in.

I do not use tape for this, but tape is a perfectly good option as long as it is archival. Regular tape yellows, dries out, and lifts over time, which defeats the purpose.

None of this makes a frame invincible. It makes it far less hospitable, which is the honest goal.

Here is the practical stack, from the flower all the way to the finished sale.

If you sell at markets or fairs, a small card tucked in with each piece sets honest expectations and protects the relationship. Here is wording you are welcome to adapt:

It costs almost nothing, and it heads off the two most common ways a piece gets damaged after it leaves you: sun and moisture.

If you do commissioned work, preserving someone's wedding or memorial flowers, your agreement should be clear about what you can and cannot control once the piece is in the client's home. Here is sample language to start from:

One important note: I am a flower presser, not a lawyer, and this is sample wording, not legal advice. Adapt it to your own situation, and if the stakes are high for your business, have someone qualified look it over. The goal is simply to make your promise, and its honest limits, clear out loud before there is ever a problem.

You cannot promise a pressed flower frame will never, ever host a bug. No one working outside a controlled, museum-like environment can.

What you can do is treat your flowers before they are framed, choose frames that actually close, seal the back, keep your studio dry, and tell your buyers the truth about caring for natural materials.

Do those things, and the odds tip hard in your favor!

For anyone who wants to read the research behind this post, here are the sources I drew on. I leaned on museum and herbarium conservation bodies and university entomology programs.

Now I would love to hear from you. What do you do to protect your framed pieces from pests and moisture? Have you landed on a sealing or treatment trick you swear by, or run into a problem that taught you something? Tell me in the comments.