Greenhouse in the Snow (gouache style)

A greenhouse is a frame of timber or aluminium glazed with glass or polycarbonate, trapping the sun's warmth and keeping off wind and rain. Timber frames insulate a little better than metal, and cedar weathers to silver-grey. In winter an unheated greenhouse keeps plants dry and sheltered, but it can still freeze inside on a clear night. That's why tender plants such as pelargoniums, citrus and young cuttings need gentle heat to get through to spring.

Before winter, clean the glass inside and out to let in as much light as possible, and clear out debris where pests can overwinter. Lining the inside with horticultural bubble wrap cuts heat loss, and a small heater with a thermostat will keep the temperature just above freezing. Water sparingly and in the morning, so plants aren't sitting damp overnight. Open vents on mild, sunny days to reduce mould. After snowfall, gently brush snow off the roof, since its weight can crack panes and it blocks light.

Here a timber greenhouse glows with light in a snowy garden at dusk. With snow on the ground and the last of the daylight going, it's the brightest thing in the scene. The moment was chosen for that contrast: cold outside, shelter within, and tender plants kept safe until the days lengthen again.