The large format. A metre fifty by a metre fifty — 2.25 m² of floor — is the point where a tent stops being a basement-corner project and becomes a serious production space, one you step into to work instead of leaning through the door.

What it actually does: complete control over light. Day length is what you program, independent of the season. The reflective inner wall sends back toward the plants the light that would be lost on the walls, so the same lamp yields more inside a tent than out in the open. The enclosure holds humidity, keeps dust and insects out, and stops the lighting from spilling into the rest of the house.

This size in particular: at 150 × 150 cm you're talking six to nine large fabric pots, or a full shelf of microgreen trays with room to move around them, or a nursery capable of supplying an entire vegetable garden plus the extras you give to the neighbours. It's also the surface at which it becomes worth treating ventilation and humidity management as parts of the system rather than as accessories: the bigger the volume, the more expensive stagnant air becomes in leaf disease.

Construction: made of durable, weather-resistant Oxford 1680D fabric. The number is the denier, the linear mass measure of the fibre: 1680D is a heavy grade, the same order as luggage and tool bags.

• Dimensions: 150 cm × 150 cm × 200 cm tall — 2.25 m² of floor.
• Oxford 1680D fabric, durable and weather-resistant.
• Reflective inner wall.
• Suited for: six to nine large pots, a full shelf of microgreens, continuous production.
• At this volume, plan ventilation as part of the system, not as an accessory.