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How To Choose Fluorescent Grow Lights For Your Grow Room

Growpackage Eco Farm
Sep 27, 2019 · 7 min read

Using Fluorescent Grow Lights in your Indoor Garden

Options for fluorescent grow lights were limited for many years. The standard 2 bulb, 4 foot long fluorescent shop light was just about your only choice. Because of the affordability of the fixtures and the huge improvements in the bulbs themselves, standard fluorescent lights are still an excellent choice.

Is fluorescent light good for growing plants?

Fluorescent grow lights are best kno w n for their propagation abilities. These lights do wonders for clones, seedlings, and young plants, since they have low heat output and a less intense light. HID and LED grow lights need to be placed further away from plants, and a lot of light is wasted. Fluorescent tubes are smaller, and save the grower money on electricity costs. These lights can also emit a full spectrum for plants.For growers trying to grow the biggest plants possible, fluorescent lighting is a great way to get plants started. Once the plants begin to get larger, it is best to switch to a CMH or LED grow light to increase yields come harvest.

Fluorescents are best for when you don’t have a lot of space.

There are times when the cannabis growing world moves slow, and then other times it changes overnight. The latter is the case for fluorescents, and you can thank LEDs.

Fluorescents are best for when you don’t have space to grow in. But in the last couple of years, high-quality LEDs have been split into rows or strips which can get them within 12in of the plant’s canopy without causing light burn. LEDs grow much bigger plants and can make up their initial cost within the first grow.

Fluorescents, particularly, the T5 Bulbs, can grow some wonderful cannabis and can pull anywhere from one to five ounces with the average indoor setup.

Why Grow With Fluorescents

The biggest benefit to fluorescents is they’re great if you want to run a single grow just to see if growing cannabis is for you. You likely won’t have the CFLs you need lying around (20+ true watts), but it’s easy finding uses for them around the house if growing isn’t your thing.

Pros of Growing with Fluorescent Lights:

Easy & cheap for first-time growers to put together

Low to medium heat output

Perfect for seedlings when using HIDs for later stages

Great for small spaces

T5 & T8 bulbs can often compete with blurple LEDs

Tips For Fluorescent Grow Lights

Growing Tip 1 — You’re going to want your CFLs within an inch or two of the plant’s canopy. Just make sure they don’t touch the plant as they will burn them. The T-series lights need to hang a little higher (8–12 inches), so you’ll need to watch for light burn like you would with HIDs or LEDs.

Growing Tip 2 — When calculating your wattage for CFLs you need to ignore the “equivalent wattage” and look for the true watts, which will be the lower of the two numbers.

Growing Tip 3 — Expect to only grow one plant at a time. While you won’t need a large ventilation system like you would with other lights, you’ll still want fans near the grow space to remove heat build up.

When should you use fluorescent grow lights?

Most large-scale and commercial operations use LED lights because they last longer and emit more light. Fluorescent bulbs are also more fragile, meaning a farmer can incur additional labor costs to maintain them, and that may not be worth the time or money.

However, the small-scale or hobby farmer may find fluorescent lights to be an economical choice, especially for low-light plants or plants at a low-light stage of development.

To make the best economic decision about lighting for your farm, compare both the capital and operational expenses of your lighting options over time. (For example, this is how HID and LED compare.) Don’t forget to factor in replacement and heat-removal costs! Another option to consider is LED light bars.

Choose a high-output fluorescent

All fluorescent lights work in a similar fashion:

An electric current heats up gas inside the tube, which emits ultraviolet light.

Meanwhile, a phosphorus coating inside the tube turns that ultraviolet light to visible light.

A ballast on the back converts the incoming electrical current into a usable form.

You’ll see several numbers on a fluorescent light that give you information about how it works, and help you avoid lights that are too dim.

Tubular lights have a “T” rating that tells you the diameter of the tube. T12 lights have that designation because they have a diameter of 12/8 of an inch or 1.5 inches. These tubes were commonly used in indoor lighting applications, but they’re just not very bright, even with a coating to make them full-spectrum.

T5 lights are narrower than T12s, with a diameter of 5/8 of an inch. Look for a T5 bulb with an additional “HO” rating, which stands for “high output.” That means the ballast has been adjusted to make them even brighter — and for growing purposes, more efficient.

“This is the preferred [fluorescent] light that we use. This is a very high output light. If you put a T5 next to a T12 and turn them on, you will absolutely see the difference,” Dr. Nate Storey says.

When buying a full-spectrum grow light, you also need to look at the Kelvin rating, which indicates how warm the light is. Fluorescent lights, in general, tend to be bluer but look for a light ranging from 5,600–6,400 Kelvin, which will be indicated on the bulb. On the lower end of that spectrum, the bluer light will give you stockier growth, while the higher rating is great for any kind of vegetation.

Fluorescent lights will also come with a wattage rating to tell you how much electricity the bulb uses, usually 54 watts.

This is the newest improvement to fluorescent grow light systems. The T5 system uses improved high output bulbs, like the ones I suggest using in the section above. They use several bulbs side by side, and there is an arched reflector behind each bulb. These lights are designed to support bigger plant growth. Their best use is for growing strong, healthy plants up to 24 inches tall in the vegetative state. T5 lights are a little expensive in my opinion, so I recommend sticking to standard fluorescent shop lights for your seedlings and clones.

One friend who has been using T5 fluorescent grow lights exclusively has told me these lights support flowering well. However, he also told me the yield is about half what you would expect from the same size garden grown under a high pressure Sodium light of the same wattage. After gardening under fluorescent lights for a year to save money, my friend is now switching to a high pressure Sodium grow light.

Choosing the Right T5 Grow Lights

To use T5 grow lights properly, there are a couple of things you need to know that will determine how successful you will be at growing under these lights. The first thing is how to choose the right T5 fixture and the right bulbs.

Fixtures: When it comes to choosing a grow light fixture, there are a couple of things to think about. First is the size requirements for this grow light. There are more than a dozen size variations, so you need to figure out the size of your indoor garden and then fit the lights to your space. T5 grow lights typically come in two different lengths and around six different bulb configurations. 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.

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.

As far as color temperatures go, different plants have different light requirements, so I can only suggest a general guideline, which is to start with 6,500 Kelvins bulbs when plants are in the vegetative stages of growth. This is approximately the color temperature of light on a summer day. Otherwise, use 3,000 K bulbs when plants start to flower. This color temperature is warmer (more sunset-like), with a red tint to it, so it will best suit blooming plants.

Options for fluorescent grow lights were limited for many years. The standard 2 bulb, 4 foot long fluorescent shop light was just about your only choice. Because of the affordability of the fixtures…

The Different Types of Lights for Cannabis: Pros and Cons

Learning about the many types of grow lights available can be overwhelming, especially for those new to cannabis cultivation. They all serve the same purpose, but many of them go about it in different ways. To clear up the confusion, we’ll be taking a look at the different types of lighting, and breaking down their pros and cons.

Let’s run through a detailed comparison of the most popular cannabis grow lights.

Contents:

Every cannabis cultivator knows how important proper lighting is when it comes to achieving a successful harvest. Along with nutrition and water, it’s one of the most crucial factors in ensuring healthy growth and bountiful yields.

Although natural sunlight is usually optimal for cannabis growing, many cultivators prefer to grow indoors for various reasons. First, not everyone lives in a climate where outdoor growing is feasible. Second, indoor growing involves timed artificial lighting, giving the grower more control over the vegetative and flowering phases of their cannabis.

With that in mind, we believe exploring the world of cannabis grow lights is more than worth it.

Pros and Cons of Different Cannabis Grow Lights

Today, you can find many different types of grow lights for indoor cultivation. But not all are equal; in fact, there are big differences when it comes to effectiveness and cost. In turn, some grow lights may be better suited for certain types of setups than others.

Let’s take a look at the types of grow lights available, and compare them relative to their pros and cons.

FLUORESCENT (CFL) GROW LIGHTS

CFLs, also known as “compact fluorescent lights”, are some of the most common you’ll see out there. You can get these lights at many places, including home improvement stores and even grocery stores.

FLUORESCENT (CFL) GROW LIGHTS

CFLs, also known as “compact fluorescent lights”, are some of the most common you’ll see out there. You can get these lights at many places, including home improvement stores and even grocery stores.

They are especially suited to small grows, and will be the most affordable starter lights you’ll find. Conveniently, these bulbs have standard sockets so you can use them with any standard light fixture. They do not require any special equipment.

You can find “daylight” CFL bulbs at 6500K or “warm white”, with a more reddish light spectrum, at 2700K. Bulbs with a daylight spectrum are more suitable for the vegetative growth phase, while warmer CFLs are better for the flowering phase.

CFL PROS CFL CONS
Low cost and widely available Low light output (only suitable for growing 1–2 plants)
Easy to set up and use Not optimal for flowering (produces subpar yields)
Good for beginners Tends to have a shorter lifespan than other lights
Available in various wattages and colour temperatures
Uses little electricity, saves energy
Doesn’t get hot
Perfect for clones and seedlings
CFL PROS CFL CONS
Low cost and widely available Low light output (only suitable for growing 1–2 plants)
Easy to set up and use Not optimal for flowering (produces subpar yields)
Good for beginners Tends to have a shorter lifespan than other lights
Available in various wattages and colour temperatures
Uses little electricity, saves energy
Doesn’t get hot
Perfect for clones and seedlings

CFL Cost and Expected Lifespan

A standard 40W CFL bulb will only cost a few bucks. This makes them great starter lights for growers on a budget! It’s a lot of bang for your buck, too, as the expected lifespan for compact fluorescents is about one year.

Yield per CFL

Expect to obtain 0.3 grams per watt (roughly 12 grams per standard light).

HID (MH and HPS) Grow Lights

HID (high-intensity discharge) grow lights are somewhat of a gold standard in the cannabis cultivation industry. Many growers swear by HID lighting and believe that they produce the best and biggest yields.

HID (MH and HPS) Grow Lights

HID (high-intensity discharge) grow lights are somewhat of a gold standard in the cannabis cultivation industry. Many growers swear by HID lighting and believe that they produce the best and biggest yields.

There are two main types of HID lights: MH (metal halide), and HPS (high pressure sodium) lights. The difference between the two is that MH lights produce a “cooler”, blueish light, whereas HPS lights are usually red. This makes MH lights more suitable for the vegetative phase, with HPS lights being better for flowering.

Therefore, most advanced growers use a combination of MH and HPS bulbs for the duration of the process. If, for some reason, you need to choose one type of HID for the entire grow, we would recommend HPS lights. 600W HPS lights are the most popular type. In most cases, you can usually get complete sets that include the bulbs, a ballast, and a reflector.

HID PROS HID CONS
Compared to high-end LEDs, HID grow lights cost less outright They give off intense heat that can spike grow room temps or burn plants
Easy to set up and operate, even for relative beginners You’ll need additional equipment to operate them, including an electronic ballast and reflector
Produces excellent yields HID bulbs degrade over time, and you will have to replace them periodically
Reliable and consistent HID lights are very power-hungry and can significantly increase electricity bills
Options for growth and flowering
HID PROS HID CONS
Compared to high-end LEDs, HID grow lights cost less outright They give off intense heat that can spike grow room temps or burn plants
Easy to set up and operate, even for relative beginners You’ll need additional equipment to operate them, including an electronic ballast and reflector
Produces excellent yields HID bulbs degrade over time, and you will have to replace them periodically
Reliable and consistent HID lights are very power-hungry and can significantly increase electricity bills
Options for growth and flowering

HID Light Costs and Expected Lifespan

As discussed, you can find complete HID lighting kits that include a lamp, a ballast, and a reflector for €150 and up. The low initial cost, however, will be offset by the higher operation cost (i.e. your electric bill).

The bulb lifespan is approximately one year. In turn, you should replace your bulbs annually to maintain optimal light output.

Yield per HID Light

You can expect around 0.5–1g+ per watt, which is roughly 300–600 grams/standard light.

LED GROW LIGHTS

Just a few years ago, LEDs were not suitable for “serious” grows, aside from providing light for seedlings or clones. However, LED technology has come a long way in a short time.

LED GROW LIGHTS

Just a few years ago, LEDs were not suitable for “serious” grows, aside from providing light for seedlings or clones. However, LED technology has come a long way in a short time.

Most quality LEDs emit a light that works for both veg and flowering, while some come with a switch to change the light spectrum according to the appropriate phase. Modern LED grow lights, such as those with COB (“chip on board”) technology or “Quantum boards”, can now provide solid light intensity and penetration, even for the most demanding grows. Today, LEDs can rival, or even surpass, other types of grow lighting, including HID lights. That being said, you need to get the right ones. These lights tend to be some of the most expensive, but they can also save you some serious money in the long-run.

LED PROS LED CONS
Most energy-efficient type of grow light (saves money and energy over time) High-quality fixtures with modern modules can put a decent dent in your wallet
LED lights run much cooler compared to HID lighting, barely producing any heat at all There is no industry standard for LED lights
Cuts back on cooling costs and reduces risk of burning plants Cheap models on the market produce inferior results
Most commercially available LED grow lights are “plug and grow”—no special ballast required Potentially lower yields than HID
Streamlined; can support both veg and flower
LED PROS LED CONS
Most energy-efficient type of grow light (saves money and energy over time) High-quality fixtures with modern modules can put a decent dent in your wallet
LED lights run much cooler compared to HID lighting, barely producing any heat at all There is no industry standard for LED lights
Cuts back on cooling costs and reduces risk of burning plants Cheap models on the market produce inferior results
Most commercially available LED grow lights are “plug and grow”—no special ballast required Potentially lower yields than HID
Streamlined; can support both veg and flower

LED Light Cost and Expected Lifespan

You may find a low-quality LED fixture for a single plant for €120. But for good LEDs from a reputable brand, expect to pay several hundred euro, even up to €2,000. You get what you pay for with LEDs, so it’s always worth doing your research and finding a reputable brand.

Good LED grow light fixtures have a lifespan of 5–10 years.

Yield per LED Light

0.5g–1.8g per watt, depending on the make/quality of the light.

LEC GROW LIGHTS

LEC lights, also called ceramic metal halide (CMH) or ceramic discharge metal halide (CDM) lights, are the last type we’ll be discussing today.

LEC GROW LIGHTS

LEC lights, also called ceramic metal halide (CMH) or ceramic discharge metal halide (CDM) lights, are the last type we’ll be discussing today.

The name also hints at the difference between LEC lights and conventional HID lights. LEC lights use a ceramic arc tube, rather than the quartz version found in regular MH lights. The result is a more natural colour, more lumens per watt, and a longer lifespan. LECs include built-in ballasts, so that aspect of setup is very simple.

While modern LED lighting is now becoming the de-facto standard in most grow rooms, LEC lights do have certain benefits. This makes them an interesting alternative to other types.

LEC PROS LEC CONS
Emits a natural light spectrum (easier to see your cannabis and spot issues) UV-B light is harmful to humans (safety equipment is needed to reduce risk to skin and eyes)
LEC lights give off UV-B rays that may improve yield or trichome production High setup cost
Simple setup and operation Generates lots of heat
Longer life-span than HID lights Slightly less powerful than HID lights
UV-B rays are blocked by glass
LEC PROS LEC CONS
Emits a natural light spectrum (easier to see your cannabis and spot issues) UV-B light is harmful to humans (safety equipment is needed to reduce risk to skin and eyes)
LEC lights give off UV-B rays that may improve yield or trichome production High setup cost
Simple setup and operation Generates lots of heat
Longer life-span than HID lights Slightly less powerful than HID lights
UV-B rays are blocked by glass

LEC Light Cost and Expected Lifespan

Decent LEC grow light fixtures start at €250–300, with higher-end models setting you back up to €1,000. The bulbs also cost somewhat more than normal MH/HPS bulbs.

On the plus side, LEC bulbs will last about twice as long as HID ones, approximately two years.

Yield per LEC Light

When utilising LEC lights, you can expect up to 1.5g per watt.

Which Lights Are Best for Growing Cannabis?

So, what type of grow lighting is best? This is a decision that will depend on various factors, including the size of your growing area, the type of weed you’re growing, and, last but not least, how much you can spend.

If you require a light for seedlings and clones, or you happen to have a “micro grow” in a very small space (like a cupboard), you are likely best off with a simple CFL light.

For slightly bigger grows, consider a decent LED light anywhere from 400–600W. As there won’t be much heat from the light, you may be okay with a simple exhaust system and a fan.

For medium to large growing operations, you can look into high-end LED fixtures and LEC lights, or go with proven HID lighting solutions.

Don’t Just Look at Wattage — Power Equivalents Between Types of Lights

Now, be aware that a 200W CFL isn’t the same as a 200W light LED, and neither are the same as a 200W HID. The wattage only indicates how much power the fixture uses, not saying anything about the light output. Because lighting technologies differ in their efficiency, you can’t compare them based on their wattage alone. The only type of light where one can expect certain yields (given a particular wattage) would be HID lights, as these are standardised.

Likewise, this also means that a LED fixture stated as being 600W doesn’t necessarily emit the same amount of light (and therefore produce the same yields) as, say, a 600W HID light. Honestly, the only way to determine true light output is to go over the specs from the manufacturer. Better yet, ask other growers for their experiences with a particular make or type of light—that way you’ll know what to expect.

Lights, Lights, Lights: Illuminating Your Options

Choosing the right grow light for your cannabis is among the most important decisions you’ll make.

If you want superb yields, you definitely can’t bypass getting at least a 600W or stronger HID light, or an equivalent LED or LEC. If, on the other hand, you’re looking after seedlings and clones, a less powerful CFL will do.

Most importantly, don’t spend money on a grow light without getting informed at first. A great “bargain” may ultimately just be a waste of your hard-earned cash. If prices for a good light are intimidating, you can also look into DIY solutions! You can find all sorts of kits online that come with the necessary parts. That way, you can save some money while getting a quality light that will serve you and your plants well.

In this article, we’ll be comparing grow lights made for indoor cannabis cultivation, looking at their pros and cons, and seeing what lighting solution is best.