Protected Culture and Nursery Practice
Core concepts
Understand protected culture: greenhouses, polytunnels, cold frames, cloches and shade netting. Learn how these modify temperature, light, humidity and wind, and how to manage ventilation, heating, shading and irrigation. Know the difference between a heated and unheated structure and the crops suited to each.
In nursery practice, understand seed sowing, pricking out, potting on, hardening off and labelling. Learn the components of a suitable growing medium: loam, peat or peat alternative, sand and compost, chosen for drainage, water holding and aeration. Understand propagation structures such as mist benches and propagators, and hygiene to prevent damping off.
Traps in questions
A common trap is moving plants straight from a warm propagator to the open garden without hardening off, causing check or death. Another is overwatering under cover, which encourages damping off and mould. Candidates also forget that ventilation controls humidity as well as temperature.
Worked example
Seedlings raised indoors should be hardened off over about a week to ten days by gradually increasing exposure before planting out. Rule of thumb: change one factor at a time, and ventilate before you water.