The standard square format, and by far the most versatile. A metre twenty by a metre twenty, two metres tall: it's the footprint most grow lights are designed and specified for, which makes choosing lighting far simpler. If you're hesitating between sizes, this is almost always the one to take.

What it actually does: a grow tent gives complete control over light. Inside, day length is what you program, not what the season allows, which means growing in January exactly as in June. The reflective inner wall sends back toward the plants the light that would be lost on the room's walls: the same lamp yields more inside a tent than out in the open. The enclosure holds humidity, keeps dust and insects away, and stops light from spilling into the house.

This size in particular: 120 × 120 cm is the space for four large 5-gallon fabric pots set in a square, or two rows of microgreen trays on two levels, or a real spring nursery capable of supplying a whole vegetable garden in seedlings. The two metres of height leave the margin needed to hang a lamp and raise it as the plants grow, which is often what's missing in shorter formats.

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, a long way from the light canvases of entry-level tents.

• Dimensions: 120 cm × 120 cm × 200 cm tall.
• Oxford 1680D fabric, durable and weather-resistant.
• Reflective inner wall.
• The reference footprint most grow lights are specified for.
• Suited for: four 5-gallon pots, a complete spring nursery, sustained microgreen production.