Collection: Indoor greenhouse

Growing Indoors Under Glass

An indoor greenhouse keeps humidity and warmth around plants inside a flat or house. That sounds redundant until you consider what indoor air actually is in winter: heated, very dry, and swinging several degrees whenever the heating cycles. Most plants that struggle on a windowsill are struggling with humidity rather than light.

A glazed cabinet or propagator box holds moisture around the foliage and buffers those swings. For seedlings, cuttings and tropical species it makes the difference between surviving and growing.

What It Suits

Three uses account for most indoor greenhouses. Raising seedlings before they go out in spring. Striking cuttings, which need consistent humidity to root. And keeping tropical species that will not tolerate dry room air at all.

Herbs and salad leaves grow well in one on a bright sill. Fruiting crops are harder indoors, since they need more direct light than most rooms provide even in summer.

Light Is the Limit

A window transmits considerably less usable light than open sky, and a room a metre back from the glass receives a fraction again. This is the constraint that catches out most indoor growers, and no amount of warmth compensates for it.

• A south facing sill gives the most light and is worth prioritising over floor space.
• Rotate pots regularly, since plants lean hard towards a single light source.
• Where daylight is short, supplementary lighting is the practical answer rather than an upgrade.

Several cabinet models include shelf lighting for exactly this reason. Our lighting range covers grow lights that supply the spectrum plants actually use.

Ventilation Indoors Too

A sealed cabinet holds humidity, which is the point, but a cabinet that is never opened grows mould rather than plants. Lids and doors are there to be used, and airing for a short period each day prevents the still, saturated air that fungus needs.

Watch temperature near a radiator or in direct sun through glass. A small enclosed volume heats faster than the room around it.

When to Move Outside

An indoor cabinet is well suited to propagation and poorly suited to growing plants on. Once seedlings are established they need more light than a room provides, and hardening off before planting out is not optional.

A cold frame outdoors handles that transition, and a balcony frame or mini greenhouse extends the same growing into open air where the light actually is.