For optimal results, for vegetative growth choose fluorescent light bulbs that are labeled either as "Cool White" or "Cool" colored (also labeled as "6500k" colored).
There are many different levels of fluorescent grow lights including the T5, the T8 and the T12. I strongly suggest sticking with the T5 style of fluorescent grow lights for cannabis because they give off the most amount of light for the size, and are specifically designed to be able to support taller plants up to 24 inches.
The biggest problem with fluorescent tubing is that the light that they give off is only useful for about a foot or so. That's why they're kept so close to your plants.
Example of a ScrOG (Screen of Green) Grow Under a T5. Using a screen can be an effective way to create a flat, table-top shape to take the best advantage of T5 grow lights
In recent years, we've seen the creation of new high-light-output versions of fluorescent grow lights which can actually be used through the entire vegetative stage.
A few years ago, growers usually only used fluorescent tube lighting as a supplemental light for cannabis plants, or for young seedlings and clones only.
In general, I recommend changing to stronger grow lights like LEDs or HIDs for the flowering stage because they will usually give you double or more yields/watt of electricity. Unless you keep your plants very small, they will need more light to produce buds than a fluorescent light can usually produce. If you're in a dire situation where your plants have grown too big and you can't afford to get a different type of light, you can supplement your fluorescent tubes with additional light, for example you could supplement their light with a few CFL(compact fluorescent light) bulbs wherever you notice any "shadowy" areas. This is only a minor fix – the real fix is to grow very short plants or upgrade to a bigger light for the flowering stage.
If the temperature is under control they can be kept as close as an inch or two away.
However, you can use either type of lights during either stage and still get good results. People also use "Daylight" (5000K) bulbs with success.
Many indoor growers are already familiar with the virtues of T5s, but even if you know your T5 fixtures and more or less know how they work, you might need help with some things, because specifics like color temperature, hanging height and light cycles might not be as easy to figure out.
Choosing the Right T5 Grow Lights
The most common T5 grow lights are 2- or 4-ft. long and have 1, 2, 4, 6, 8 or 12 bulbs per fixture. If you are thinking of growing only a few small plants, you might get away with having a 1- or 2-bulb set-up that is 2- or 4-ft. long, but if you want to grow a whole bunch of plants, you will have to invest in an 8- or 12-bulb set-up that is 4-ft. long. This larger size will cover a lot of plant mass without using too much electricity.
Setting Up the T5 Lighting System
Bulbs: When it comes to choosing bulbs, there are even more options to choose from. Bulbs not only come in different energy varieties, but also in different color temperatures. When choosing between normal output (NO), high output (HO) and very high output (VHO) bulbs, I recommend going for the middle ones. HO bulbs are the best of both worlds—they are efficient, yet long-lasting, and will provide super-bright light for your plants.
The product conducts a voltage of 110 or 120 Volts, which is the average voltage of a regular outlet. This way, you should have any problem finding a power source since you can use a common extender. As T5 grow light fixtures go, this set is designed for 8 T5 bulbs that have the power input of 4 Amperes to provide soft and pleasant-to-the-eye daylight. Meanwhile, the temperature color power amounts to nearly 7000K to resemble a slightly cloudy day, not to expose your cannabis to an excess of light.
It’s designed to be an easy-to-install set that fixes firmly to a surface without wobbling or unnecessary rattling. Thanks to the 12 inches in width, the lights are quite portable and can be relocated when needed. Also, there is a nice 3-headed outlet in the back to adjust nicely with comfortable access to a power source.
iPower 2-Pack T5 Fluorescent Grow Light System — Fixture With Impressive T5 Grow Light Bulbs
If you find yourself looking for good-enough lighting for your cannabis tent, consider this one. It combines a compact size with nothing too odd but high-quality performance. Also, this T5 grow light kit requires very little maintenance, which results in the longevity of the whole fixture and safety for the plants.
Both of them are good enough, but I’d prefer to use T5 since they have already proven more than useful in my experience.
Types of T5 lights
This 4-foot is designed for hanging right above the cannabis in three different modes. First, it’s possible to hang it using a set of carabiners that clip firmly with fixtures. Second, it can take either a vertical or horizontal position, depending on the place you find the most suitable for it. Finally, you can chain the lights to premade hangers or simply fix the lights on a surface.