1. The first step is to determine how much light you need. This depends on the size of the greenhouse and the kind of plants you plan to grow. Tall plants, fruit and flowers need more light than other plants. An outdoor greenhouse will typically use 25 watts per square foot. But an indoor greenhouse will need twice as much light or more.

2. The kind of light you use should be suitable for the plants you’re growing. The type of light waves produced has a significant effect on plant growth. For instance, if you want optimal growth for fruit or flowers, use high pressure sodium lights. These give off red light waves which are beneficial for encouraging growth hormones in plants. If you’re growing leafy plants, they’ll thrive under the blue spectrum, which metal halide lighting is best at providing.

3. Don’t let your lighting overheat your plants. Too much heat can kill them. Some kinds of lighting give off a considerable amount of heat. For instance, incandescent lighting gives off a lot of heat. Since the light they provide isn’t considered to be sufficient for most plants, they’re really not a good choice. However, fluorescent grow lights give off a lot less heat. Make sure you compare how much heat each lighting option produces before making your purchase.

4. Use lighting that will produce good results without consuming massive amounts of energy. High intensity discharge lights are the most energy efficient type of indoor greenhouse lighting available. Unfortunately, they’re also the most expensive to purchase. Another option is LCD grow lamps, which are a popular choice due to their high energy efficiency. As well, they give off less heat.

No matter what kind of indoor greenhouse lighting you decide on, it’s essential that you turn it off from time to time. Use lighting wisely, only when and where it’s required. For optimal growth, plants need a certain amount of darkness. Depending on the type of plants you’re growing, you should have the lights turned off in your garden greenhouse for anywhere from six to twelve hours daily.