The Complete Guide to Grow Lights for Succulents
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There comes a point in every succulent addict’s journey where they begin looking into purchasing grow lamps to help their indoor collection thrive.
There are a lot of reasons you might want a grow light (also referred to as a grow lamp). Perhaps none of your windows can provide enough light to your windowsill plants. Perhaps, like me, you’ve just run out of space on every window sill.
Or, maybe you’re trying to overwinter your succulents indoors without them suffering etiolation.
Grow lights are gonna change the way we play this succulent game. They are an easily implemented solution that increases your plant capacity. Your obsession will be enabled to a greater extent than ever before.
What are Grow Lights?
“Grow light” isn’t a technical term, nor is it a unique piece of technology. Any light can be a “grow light” since plants really aren’t that picky about where the light comes from.
What sets grow lights apart from regular lights is the spectrum of light they emit when powered. Your typical lamp uses “soft” and/or “warm” light (which are terribly vague, informal descriptors of light quality and intensity). They tend to be yellowish and fairly weak as far as lumens (light power) are concerned.
Grow lights are often (but not always) “full spectrum” lights. That means they contain the full visible spectrum of light, from red to violet, plus a little extra on both sides – a touch of ultraviolet light can be beneficial. These lights are often described as “white/blue” or “cool” or “daylight”.
So, no, they don’t function any differently than other lights. The spectrum a lightbulb produces is determined by the components with which they are manufactured.
Why Use a Grow Light?
They’re pretty nifty for hobby gardeners and commercial growers alike. Here are some common uses for grow lights:
- Growing plants entirely indoors
- Starting seeds or propagations
- Extending the growing season of some herbs and veggies
- Supplement insufficient natural light
That last one is pretty important to us succulent-growers. Have you had ever problems with succulents turning out just plain green instead of all those vibrant colors Pinterest promised? Or you order plants that look really pretty and then slowly fade to dull green over a few weeks?
Yup, that’s because they haven’t gotten enough light (or not enough strong light). You can kind of break down light needs into 3 levels.
- Level 1 – The bare minimum amount of light a plant needs to survive. It’s quite low, actually, in the case of most succulents. Internal rooms of a house would often be at this level.
- Level 2 – This is the minimum amount of light a plant needs to avoid etiolation (stretching). There’s a pretty big gap between level 1 and level 2. It’s totally possible to have a plant under a grow light and it still become etiolated (if the light is too far away or not strong enough).
- Level 3 – The amount of light necessary for a succulent’s “true colors” to appear (also called “sun-stress” or “sunblush”). The gap between level 2 and 3 isn’t that wide, actually. Once you’ve successfully avoided etiolation, it usually just requires a little more light.
That’s hardly a scientific explanation, but it helps to know what you’re up against. Although every plant is different, the answer to most of the aesthetic issues of succulents is just more light.
Grow lights are especially useful for windowsill succulents. South-facing windows have the best light (if you’re in the northern hemisphere). I’ve found that those are the only succulents in my house that develop their sunblush naturally. Succulents in any other window tend to stay green unless they also get a little love from a grow light.
This is especially pertinent during winter when both daylight hours are shorter AND light intensity is lower. Your succulents are at increased risk of not only becoming a boring green but also becoming etiolated… for which there is no cure.
Except for beheading. Seriously.
Types of Grow Lights
There are a couple main types of grow lamps. We will ignore the incandescent ones for a few reasons: they’re energy inefficient, the produce too much heat, and they don’t hit the proper light spectrum. Let’s talk about fluorescent and LED grow lamps.
Fluorescent Grow Lamps
Tube lights come in several flavors, but there’s a clear winner you should pretty much always choose.
You’ve seen the T5, T8, and T12 stuff, right? Well, the ‘T’ just means tube, while the number denotes the diameter in eighths of an inch. Therefore, a T5 is a tube light with a diameter of 5/8 inches. Tube lights can come in any length, but 1, 2, 4, and 8 foot are most common.
Also, tube lights will often come in a large fixture with multiple tubes. These are meant for scaled-up growing operations and are accordingly more expensive.
As it turns out, you should really only ever buy T5 lights. Both of the other kinds are older technology that is significantly less efficient. T5s last longer, use less energy, and produce more light.
I use a couple of single tube lights to supplement my windowsill set up. This is the one I’ve been using, and I’m pretty pleased with it.
If you don’t have space or don’t like the aesthetic of a long, tubular light, grow lights also come in the CFL variety. That acronym means “Compact Fluorescent Light”.
These are just like regular light bulbs and can fit in any regular socket. If you have one or two plants on a desk in your office or at home, these are an ideal fix. Just switch out that old bulb on your desk lamp with one of these bad boys and get growin’!
Note that there also exists High Output and Very High Output (HO and VHO, respectively) fluorescent bulbs. They are exactly what you think – they put out more energy and light! If you choose one of these types, make sure you hang them further away from your plants, as they put out more heat!
LED Grow Lamps
LED stands for “Light Emitting Diode”. It presents a unique opportunity for growers – it allows you to give your plants specific wavelengths of light!
Why is that useful? Well, it just so happens that most plants really only care about two kinds of light. Red light and blue light.
This is a generic graph of the light spectrum utilized by the majority of plants. Notice that plants primarily use light of a wavelength that appears red or blue. There is a conspicuous lack of green light being used. That’s because chlorophyll (the thing that makes energy from light) is green. It reflects green light, rather than absorbing it. That’s also why most plants are green-colored!
Back to LEDs. Why give plants all this extra light they’re not even going to use? Each diode in an LED only emits a very narrow range of wavelengths, effectively just one color of light. In doing this, they save even more energy and produce less heat than fluorescent bulbs!
That doesn’t mean they are necessarily better though. Giving a plant only specific wavelengths of light can trigger it to behave differently. Some plants, for example, are encouraged to flower when exposed to specific ratios of red to blue light.
Mostly though, LEDs are a cost-effective way of ensuring constant vegetative growth (new leaves and the like). It’s also used to germinate seedlings since it produces very little heat.
The biggest downside to LEDs is that they are often lacking in light power (lumens) and light intensity. It’s very difficult to get proper sun-stress colors using LED because they produce virtually no UV light (which is a part of light intensity).
Like the fluorescent bulbs, LEDs come in many different shapes and sizes. There are tubes, CFLs, fixtures, and even rolls of LED tape. You are sure to find one that fits your need if you look!
Positioning Grow Lights
There are a variety of factors that influence where you put your grow lights.
The goal is to balance light distribution with heat. Bulbs (moreso fluorescent ones) produce heat that will absolutely burn your plants if it’s too close. Yet, you want them to be close in order to maximize the amoount of light they receive. Also consider that you probably want a bulb to illuminate more than one plant at a time!
If you’re using a simple LED or fluorescent bulb without any extra gimmicks, anywhere between 3 inches and 6 inches away from your plants will give you the best results. Of course, the exact distance depends on a plant’s tolerances to light and heat.
Does your grow lamp have a hood? Hoods reflect light down towards your plant (good), but they also reflect heat (bad). When using a hood, give your plants a few extra inches of space so that you don’t scorch them.
Always monitor your succulents closely for a few days after changing lighting conditions to see how they react. It’s possible to give them sunburns if the light is too intense or on for too long.
Best Grow Lights for Succulents
People often ask me to recommend a grow light for their situation. I encourage you to do your own research, but here are ones that I’ve used personally (or had recommended to me).
In general, I would opt for full spectrum grow lights whenever possible. The plants evolved with sunlight after all, so it makes sense to emulate it as best we can.
Best Supplementary Grow Lights
Like I mentioned earlier, I’m a big fan of tube lights. I have a couple of shelves around that have some tube lights hung over propagations and baby plants.
If I ordered more, I would get ones that have a reflector this time around. I notice there’s a lot of wasted light in my current set up.
Best Desk or Table Grow Lights
My desk is the kitchen table so… I don’t currently use one of these. However, I’ve given these away as gifts before to great appreciation.
I think that gooseneck clip-on lamps are best for use on desks. They can be out of the way and still adjusted to hit that little Echeveria that needs some love. These lights work well on windowsills too. If you’re really feeling wild, they come in variations with 3 heads.
Did we miss anything? Do you have other questions? Ask below!