Get the conditions right.

A useful daily routine

Check the thermometer, feel the compost below the surface, open vents when needed and look closely at the plants. A regular five-minute inspection often catches a problem before it spreads. Keep a clear path so every crop is easy to reach.

Start with two or three crops

Tomatoes, a cucumber and a few salad trays make a useful first season. Leave room for their mature size, and resist filling every bench with seedlings. You can add more variety once you know how the greenhouse behaves in summer heat and cold weather.