Grow Lighting

grow lightingWhen building an ideal indoor growth environment, the goal is to replicate sunlight utilizing grow lighting equipment. Surprisingly, technology has come quite far in allowing us to mimic the photosynthesis process typically provided by the sun. However, not all artificial grow lighting designs are created equal.

Incandescent bulbs are the cheapest and most readily available option for many who are new to indoor growing. Although this type of standard hardware bulb may work for a single plant or when combined with regular sunlight, they have many drawbacks and safety concerns. This is true for both the plant as well as the user. Incandescent bulbs produce a great deal of heat and are almost always not the best investment for ease of use or plant growth.

Technological advances in fluorescent lighting have come quite far in recent years. So much so, that certain fluorescent light options now rival the High Intensity Discharge (HID) lights that have long dominated this industry. It is necessary to note that fluorescent lights do vary widely. For starters, the most common variety being known as the “shop light” – a four-foot by two-foot simple fluorescent two-lamp setup, which typically costs less than US$40 at most hardware stores. Herbs and plants that require little lighting can thrive with this type of fluorescent. However, if you intend to grow seedlings or other plants which require more light, a simple shop light will likely not suffice.

Depending upon the investment you are willing to make, some of the newest High Intensity Discharge (HID) bulbs can actually meet the sensitive temperature and varied light spectrum needs of many varieties of plants. This advantage will allow you to maintain a year-round supply of fresh veggies and herbs. In addition to helping your spring seedlings get a head start before outside transplantation.

Types of Grow Lights

Regardless of which type of grow light you choose, none are truly comparable to a sunny day. Indoor lighting is, however, a fantastic way to extend your growing season. After considering your budget and specific plants’ needs, select the type of light which suits you best. Remember to use care when placing lights as some require a minimum clearance of 360 degrees around the light due to the heat generated. Always check your specific plants’ needs and never leave indoor lights on longer than 16 hours a day. This would be more than typical maximum sunlight conditions and could harm the plants.


Incandescent bulbs are the classic light bulbs almost everyone is likely to be familiar with. While these are by far the least expensive option, costing only a few dollars each, the heat of these bulbs requires several feet of space in order to prevent damage to the plants. We only recommend incandescent bulbs be used in conjunction with sunlight, and with caution.

If you do choose to go with this type of lighting system, know that an incandescent bulb will work best for smaller plants. A quality bulb, around 150 watts, should cost approximately five dollars ($US) at your local hardware store. While this purchase will likely keep a small house plant growing, it really is not your best bet for starting a functional indoor garden.


Fluorescent lights are a long-time favorite of indoor home gardeners. Most fluorescent bulbs only produce a limited range of light, which typically doesn’t allow for plant flowering. Generally fluorescent lights are best suited for germination and vegetative growth. However, some of the newest “T5 Lighting Systems” produce a wider light spectrum for all-purpose use! Many favor fluorescent lights because they have a lower risk of heat damage to plants. Additionally, they are generally safer, more versatile and more effective than incandescent bulbs while still managing to remain cost-effective.

High Intensity Discharge Lamps

High Intensity Discharge (HID) lights are some of the best options on the market, although they can be considered more difficult to operate. Additionally the initial financial investment for an HID lighting system will be pricier than either an incandescent or fluorescent option. HID Lights come in four types (High Pressure Sodium (HPS), Metal Halide, Low Pressure Sodium, Mercury Vapor) but only two of these apply to indoor growing: Metal Halide (MH) and High Pressure Sodium (HPS). Both of these types typically come in two sizes: 400 or 1000 watt. A 400 watt lamp is recommended for an area of approximately fifteen square feet. A 1000 watt lamp is recommended for an area of approximately fifty square feet. For fastest growth, it is recommended to use approximately 25 watts of HID light per square foot of garden.

Both Metal Halide (MH) and High Pressure Sodium (HPS) are types of high intensity discharge lighting. All HID lights are highly efficient. Metal Halide bulbs produce light on the blue spectrum, which enhances growth, but does not help with plant flowering. Metal Halide lamps will provide optimal blue-white color for approximately 10,000 hours – the lamp will likely still provide light beyond 10,000 hours, but the quality of the light will be diminished so it is recommended to replace the lamp at this time. MH bulbs provide an excellent primary light source which will help keep plants compact while still promoting leafy growth.

Along with Metal Halide, a High Pressure Sodium (HPS) light may be a good addition to your indoor garden, as the red-orange light produced by these bulbs are much more effective than MH at producing buds and flowers. As a note, an HPS lamp also has roughly twice the lifespan of an MH lamp. When discussing HID lighting, the ideal solution is to invest in both metal halide and high pressure sodium bulbs, and to use both in tandem. The MH lights will be used first, to promote leafy growth – then the HPS lights can be swapped in to encourage plants to flower.

Light Emitting Diodes (LED’s)

Light Emitting Diode (LED) lights are the newest technology on the market for indoor grow lights. LED lights create almost no heat. Therefore, eliminating the risk of plant and property damage or personal injury. In addition to this, they are also the most efficient type of lighting available. LED lights are often programmable, and can most-closely replicate not only the temperature of sunlight but also both the red and blue color band spectrums needed for vegetative growth and flowering. LED grow lights are currently the most costly lighting option, but prices are expected to fall as this new technology ages.

Additional Tips for Success

  • How long grow lights should be run depend on the plant and its needs. Most plants and vegetables need about 10 to 12 hours of light per day in order to grow. Plants that produce fruit or flowers will need more: up to 16 hours a day.
  • Measuring kilowatts hours is the method used to determine the efficiency of the plant’s yield. Regardless of what type of lighting system you choose, this is the formula for computing operational costs:
    • Begin by taking the combined wattage of all the lights you will use and divide it by 1,000 to get the kilowatts used.
    • Multiply the kilowatts figure by the amount your electric company charges per kilowatt hour (kWh).
      • Once you get the operating cost per hour, you can multiply that by hours used per month to get your monthly operational costs.