What Grow Lights to Use to Grow Weed Indoors

Written by Jared Perkins Saturday, 14 May 2011 10:26

The two most basic things every plant needs are water and light. For the indoor grower it is very important to know what type of light to give their plant. Without knowledge in this area your harvest will be very disappointing. While hard to crack, once you gain understanding in lighting you will be on the fast track to growing success. In order to get there you are going to need to understand both old and new concepts.

The two most basic things every plant needs are water and light. For the indoor grower it is very important to know what type of light to give their plant. Without knowledge in this area your harvest will be very disappointing. While hard to crack, once you gain understanding in lighting you will be on the fast track to growing success. In order to get there you are going to need to understand both old and new concepts.

The first thing you need to understand is the Kelvin Scale. Color Temperature is rated by the Kelvin Scale (K). Cool colors, like blue-white, have a higher K value (5000+) than warm colors, like yellow or red (3000). You can identify where a light's output is on the scale by checking the box or the bulb itself. The K that is best for vegetative growth is 6500K and 2700K is what is required for the best budding. This is crucial in order to give your plants the right type of light for each phase and in turn give you the best yield. It is also smart to mix up frequencies for each cycle. A good rule of thumb is to have 70% of the total light on a plant be 6500K for vegetative growth with the remaining 30% being 2700K, and then switch to 70% 2700K and 30% 6500K for budding.

Another important term for understanding bulb output are lumens. A lumen is the SI unit for measuring luminous flux, or the perceived strength of a light as seen by the human eye. In my opinion the more lumens the better. A standard 100 watt equivalent compact fluorescent lamp (CFL) bulb with a color temperature of 2700K will produce around 1,700 lumens, but a 400 watt high pressure sodium bulb can produce 50,000! Lumens are the best way to measure the power of a bulb and therefore the amount of energy that it can provide for a plant. A bulb that has fewer lumens will not penetrate a plant as well and will need to be placed as close as possible to a plant in order to provide it with the energy that it will take to grow a lot of bud. The type of bulb will greatly effect the amount of lumens it creates. This can also determine the density of a plant's buds.

Some growers are rethinking their setups since the emergence of CFL bulbs. CFL bulbs are easy to find, cheap to buy, and use a fraction of the energy of even a standard bulb. Just a couple well placed 6500k CFL bulbs can get a plant through the vegetative phase. During fruiting is where a CFL's performance drops off the map. A full cycle CFL grow will produce small fluffy buds that will leave you wishing you had used a HPS 10 times out of 10. CFL's are great accessory and vegetative light, but they lack the lumens and penetration to effectively bud your plants.

Weather it is with CFL, high pressure sodium, or metal halide you should choose your bulbs carefully. Growing weed indoors requires that you do so.