What is the difference between a net house, shade net and polyhouse, and which is cheapest?

These are different levels of protected cultivation. A shade net house uses a net that cuts a percentage of sunlight, mainly to reduce heat and light intensity and protect crops in hot conditions, often used for nursery, leafy greens and some vegetables. A net house, often an insect-proof net house, uses fine mesh net to keep out insects and reduce pest and virus pressure while letting in air and most light. A polyhouse uses plastic film to enclose the crop fully, giving the most climate control but also costing the most. In cost terms, shade net and net houses are considerably cheaper than a polyhouse, usually a fraction of the per sq m cost, which makes them the lower-risk entry point into protected cultivation. Many growers start with a shade or net house to learn before investing in a polyhouse. Pick based on your need, heat reduction points to shade net, pest and virus exclusion points to an insect net house, and full climate control points to a polyhouse. Confirm current per sq m costs and subsidy for each with your district horticulture office.