A cloche's plants are a fortnight ahead of the rest

Seven glass bell cloches, drawn in a row along a bed, seen from slightly above and to one side. Each one is transparent — just an outline — with the seedling underneath it showing straight through. The row recedes, so the nearest cloche is largest and the far ones step down in size towards the edge of the frame.

Nothing about a cloche is complicated. It's a bell of glass with nothing inside it but warmer air.

What is a row of cloches actually doing to the plants underneath?

Giving each one its own small pocket of warmer, stiller air than the bed around it.

A cloche has no heater and no fan. It's a static object that does exactly one thing: it stops warm air escaping upward and sideways the way it would over open soil. That's the entire mechanism, and it's enough to shift a seedling's whole season.

Why does trapping air make any real difference?

Because warm air rising off sunlit soil is normally lost straight into the wider garden, and a cloche simply refuses to let it go.

Through the day, sun warms the soil and the soil warms the air just above it; over open ground that warmed air drifts off and is replaced by cooler air from around it. Under a cloche it has nowhere to go. It stays put, the glass slows the loss of heat overnight too, and the plant underneath is growing in conditions closer to a fortnight further into spring than the bed two feet away — the inverse of the low corner of a plot where cold air pools instead of warm air escaping.

What makes a good print of a row of cloches?

Drawing the glass as glass — transparent, with the plant showing through — rather than as a solid bell shape sitting over an invisible seedling.

A cloche's whole function depends on light passing through it, so an opaque outline would be a picture of a very small greenhouse doing nothing. Keeping each one as an open line with the seedling visible inside is what keeps the drawing honest about what the object actually is.

Who owns the shape of a bell cloche?

Nobody. The bell shape is centuries old and belongs to no manufacturer — plenty of glassblowers and plastics firms have made their own version of the same idea.

A specific maker's cloche — a particular ridge pattern, a branded handle knob, a company's own product line — is a different matter, licensable the ordinary way if a real one is genuinely the point. Left generic, the shape stays what it has long been: a bell, and nobody's bell in particular.

Does one cloche do anything, or does it need the row?

One cloche does the full job on its own — the row is a choice about the bed, not something the mechanism itself needs.

A single cloche over a single plant traps air exactly the way a row of seven does; the effect doesn't depend on neighbours. A row simply moves the whole method along a line of a crop rather than one specimen, the same choice a grower makes between a single grafted tree and one trained flat along a wall for its whole length — one mechanism, applied at a different scale.

Isn't a cloche just a tiny greenhouse, so why not use a proper one?

Scale and speed, mostly. A cloche goes over one row for a few weeks and comes off; a greenhouse is a structure a grower commits to for the season and for the space it takes up.

The two solve related problems from different distances. A greenhouse manages an entire climate with vents that open and close on their own — the same wax-driven arm that lifts a greenhouse vent when it gets too hot has no equivalent on a cloche, which has to be lifted off by hand once the plant outgrows it. A cloche is the minimum version of the same idea, sized to one row rather than one building.

Does it print well?

Yes, provided the cloches stay as outlines rather than being filled in solid.

Pale green picks out the seedlings inside each bell; charcoal draws the glass itself as a clean, unbroken line. Keep the row's recession honest — genuinely smaller cloches towards the edge, not just thinner lines — since the size change is what reads as depth rather than as seven identical shapes stacked flat.

How do I get one made?

Describe your row at JustOG — how many cloches, what's growing under each one, and how far the row should recede. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

Seven bells of trapped air, and not one of them doing anything more complicated than staying put.