Commercially produced living salads in the UK are grown in large greenhouses which produce over 7,000 trays per week. Placing the grow light in an upstairs bedroom gives the advantage of keeping it consistently warm (heat rises in the house) and supplementing the light is much cheaper than heating a greenhouse. In large greenhouses the atmosphere is often supplemented with carbon dioxide which plants take in through photosynthesis.
Not all salad leaf types are suitable for growing as baby-leaf salads. There are varieties that work well for cut-and-come-again harvesting where a few leaves can be removed every week, extending production over a longer period, such as: oak-leaf lettuce, which always grows reliably; loose-leaf lettuce, which a few varieties that produce reliable leaves that don't brown at the edges; spinach, which is a strong variety with resistance to bolting; rocket (Arugula), which is always good to add a delicious flavor to salad mixes, which tends to produce hotter, smaller leaves.
The Garland Grow Light Garden comes with four trays and the option of a self-watering base which is a reservoir with capillary matting to wick the moisture up to the trays. Each tray is filled with sterile potting compost/soil suitable for seeds and spread about a teaspoon of seeds over each tray covering them with a thin topping of soil. Finally, good watering is given with a fine-rosed watering can.
Once the seeds had germinated the light needed to be kept on during the day and switched off at night. Generally a grow light should be on for about 14-16 hours and off for at least 8 hours of darkness to ensure that the plants keep their natural rhythm of growth.
Fluorescent grow lights can grow plants indoors, but produce much smaller plants and are generally considered to be far inferior to both metal halide and high pressure sodium grow lights. Fluorescent lights are most often used with seedlings or clones, as the light produced is gentler on fragile plants.
Metal halide grow lights should be used for the vegetative stage of plant growth. Metal halide grow lights will produce strong light in the blue and white spectrum which effectively mimics a typical summer day. High pressure sodium grow lights will produce strong light in the red spectrum which mimics the angle of the sun during fall. When plants are ready to start flowering one should switch from metal halide grow lights to high pressure sodium grow lights.