Raised beds and borders may be used in a greenhouse or conservatory to provide a permanent planting area. Raised beds are particularly useful in alpine houses where sharp drainage is required. Borders may be created to grow summer crops; these areas may be covered by temporary staging during the winter months to create an area to overwinter tender plants.

Raised Beds

Raised beds may be constructed in greenhouses to create an attractive area in which to grow and display plants. For safety reasons, bench-height beds should only be constructed in lean-to greenhouses or those with a high brick base; glass-to-ground greenhouses should use beds of half that height or less. Alternatively, a stone trough placed on brick pillars may be used - this would be quite adequate for small plants that do not require a great depth of soil. When building a raised bed you must make sure that you leave a large gap between the bed and the wall of the greenhouse to allow air to circulate. This will prevent the moisture in the compost from penetrating the greenhouse wall.

Borders

Plants may be grown directly in a greenhouse or conservatory border; however, borders should only be created in glass-to-ground models to ensure that plants receive sufficient light.

Beds should be approximately 1 m (3 ft) wide, and at least 45 cm (18 in) deep, with a 15 cm (6 in) layer of drainage in the base. Avoid using garden soil in beds as it may harbour pests, disease and weeds. Use a good loam-based compost instead as this contains nutrients and trace elements that will not leach out as quickly as general purpose composts. Add in 10 litres of organic matter to every square metre of border - humus-rich leaf mould is particularly good for tropical plants.