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It feels a bit weird to be going on about the amazingness of using grow lights for house plants when we’re about to go into an energy crisis.
I’m not currently using mine. I love them but now is not the time. Perhaps I’ll flick them back in the depths of winter, but we’ll see.
They’re not expensive to run (mine aren’t anyway), but they are a luxury so I’ll keep them off until they’re needed.
House plant grow lights are definitely a nice-to-have, rather than a necessity (unless you live in a cave). If you have a dark house then there are plants that will do fine (ferns, Calathea, many Philodendron) but grow lights throw your options wide open.
You can use normal LED lights as grow lights in certain situations, but buying plant-specific grow lights will yield the best results.
Do grow lights really make a difference?
YES.
Grow lights make a MASSIVE difference when it comes to growing house plants.
I have an article here on which plants specifically thrive under grow lights, but most species will appreciate that extra energy.
I’ve used cheap grow lights for a long time, and they work well at keeping your plant healthy, especially during the window.
The real difference came, however, when I was sent a Mars Hydro grow light. It isn’t even one of the big fancy ones – definitely more for the casual hobbyist rather than professional farmer but it’s SO GOOD.
I also got sent a cheaper Bestva light, which also works really, really well, it’s just that bit less powerful.
The benefits of using grow lights for house plants
FYI I saw benefits from using grow lights within days. They are seriously effective.
They promote faster growth
Light is the best way to guarantee faster growth of your house plants.
Putting plants outside in summer is a great way to get a lot more leaves quickly.
HOWEVER
Outside can be dangerous for plants. If you don’t acclimate them properly, you can end up accidentally burning them to a crisp. Animals can eat/pee in them. They dry out a lot faster, and you might not notice.
Grow lights allow you more control. The light isn’t as hot as sunlight, you can control the brightness, and, crucially, the light won’t change direction.
I always put my plants outside in the shade, but as the planet revolves, what once one shade can become really, really, freaking bright.
Grow lights also work in winter. Oh, and putting your plants outside is great if you have an outside to put them in, but not everyone does.
They promote larger growth
More energy = bigger leaves.
This was most obvious in my Rhapidophora tetrasperma:
Look at the leaf on the left that I’m holding, and the big one. Quite the size difference, no?
It actually looks like I’ve tried to manipulate the photo, and that the big leaf is closer to the camera, but if you look closely, the leaves are actually touching.
So not only do we get more leaves, but they’re larger too. This is not just great for aesthetic reasons – the larger leaves a plant has, the more energy it can absorb from the light, therefore allowing even bigger and faster growth.
They can help maintain variegation
There’s a bit of an argument amongst house plant owners as to how much light affects variegation. I personally think that more light = better variegation, but only to a certain point. Some plants can be bleached by grow lights – look at this Philodendron squamiferum:
At first I was like ‘woohoo! It’s variegated!’ but I soon realised that it is, in fact, bleached by the grow lights.
You can absolutely turn the brightness down on your grow lights, but I find that some of my plants – such as Hoya and Pothos – LOVE the bright light, so I move the bleached ones further away instead.
They improve the health of the plant
Plants that are growing well are healthier. One of the easiest ways to tell if a plant is healthy is to look at how well it’s growing.
Light is pretty much the most important factor in determining how healthy a plant is going to be when you bring it home. It’s also one of the factors we have the least control over – compared to, say, watering or fertilising.
We also tend to overestimate how bright a space is, partly because we tend to buy house plants for aesthetic reasons – I’ve been asked to give plant suggestions for various spaces over the years, and a LOT of the time people are like ‘I’m gonna give it a go anyway’ when I advise them not to put a Hoya in their dark hallway.
Now I’m like ‘pick a space, pick a plant, and I’ll tell you what you need to make that happen.’ There are often grow lights involved.
They reduce the risk of pests
This is an extension of grow lights helping to improve the health of your plant.
For a start, pests are less likely to set up camp on a healthy plant. Unhealthy ones are much easier to infest.
When you’re perusing the dead and dying reduced section at the plant shop, check extra carefully for pests. A lot of the time the plants are overwatered and rotting – those ones are salvageable. The pest-infested ones probs are salvageable BUT they may infest your plants at home.
Be careful.
Healthy plants have more chance of being able to beat pests. In the wild, plants have mechanisms that allow them to do so, such as developing extrafloral nectaries that attract pest predators.
One of the easier ways to fight pests is to put your plant outside and allow other beasties to snack on the bad bugs.
Unfortunately, plants tend to get infested when they’re weakened, and they tend to be weakened in winter, when casually shoving your plant outside for an hour or two could potentially kill it. And there aren’t even any predatory bugs around.
Grow lights can help your plants stay stronger over winter, so they’re less likely to get pests.
Strong plants can still get pests, but they’re likely to respond to treatment faster, and take less damage.
They allow you to put plants wherever you want
You’re only limited by your imagination and the availability of power outlets.
If you can get bright enough lights and leave them on 8+ hours a day, you can keep any kind of plant, even a cactus, in a dark room.
From the research I’ve done, I can’t find any evidence to suggest that sunlight is superior to artificial light.
They’re energy-efficient
A lot of the research done into producing grow lights is geared towards making them as energy efficient as possible.
This has nothing to do with the house plant community. We’re just reaping the rewards.
Growing produce such as tomatoes indoors (they grow food in old WWII bunkers under London) not only saves space (you can really cram the plants in), but you can control, er, everything.
Climate change has meant that freak weather events such as high winds, flash floods, and extremely high temperatures can decimate crops in literally seconds. Growing plants underground means we don’t need to protect them from the elements – and we can grow crops year-round.
Developing energy-efficient lights is key to growing food, hence why so much research and gone into it, and why LED lighting is so efficient.
They’re full spectrum
(If you buy full spectrum ones, anyway).
This is a bit of a throwaway benefit, so move on to the next section if you like.
Full spectrum is a marketing term. It doesn’t HAVE to mean anything. But it’s meant to mean that it mimics natural daylight.
Don’t think you have to buy purple lights. Plants like a bit of white light too. The reason the purple ones are all over Amazon when you search for grow lights is that red and blue diodes are the cheapest.
The problems with using grow lights
They’re an investment
The Bestva grow lights are pretty great, and they’re around £75ish.
I think that they’re worth it, but it’s extremely difficult to tell because I was sent them for free.
Also, £75 is nothing to some people, and unattainable to others.
If your plants are currently growing well enough and you’re not planning on getting any more, then give them a miss.
Bear in mind that whilst plants grow much faster under grow lights than a sunny window (depending on where you live), they will also require more maintenance.
You’ll need to water far more frequently (the plant will use more water and the lights will dry out the soil faster) and feed more.
Also, you’ll have bigger plants. If you don’t need or want bigger plants, then it’s probably not worth investing in grow lights.
They’re not aesthetically pleasing
This is my biggest bugbear.
My individual plants are looking great, but the whole set up looks industrial, and not in a good way.
Exhibit A:
You may notice that some of the plants look crap. That’s because I often use the lights as a little hospital area for the sick and infirm.
My Pilea peperomioides LOVES her spot.
The house plant market is big, so I’m hopeful that we’ll be getting some aesthetically pleasing grow lights at some point. Something that clips onto a shelf rather than needing to be suspended would be good.
The blue light isn’t great for humans
Do. Not. Look. Directly. At. Your. Grow. Lights.
Grow lights aren’t a different type of light to normal LED light bulbs. They’re not magically trained to grow plants.
The only difference between grow lights and normal lights is that grow lights are incredibly bright.
They can cause burning
Don’t let your plants touch your grow lights – they will burn.
I’ve not had any issues with burning unless there’s direct contact with the light.
Your plants are more than happy to grow directly into the light, so you may either have to rotate them, prune them, or move them further away.
They can cause bleaching
Bleaching looks very much like variegation, so don’t get them confused. I don’t know how to tell the difference, because they’re both caused by a lack of chlorophyll.
Too much choice
I was lucky to get sent my lights because there is SO MUCH CHOICE when it comes to grow lights.
Not only that but there’s no easy way to tell if the specs are good because companies manipulate them to sell more. I tend to go by the lumens because that’s the brightness, but I imagine a lot of grow light experts would disagree with that.
Even reviews can be manipulated, and it’s hard to sift through them all.
I highly recommend the Bestva and the Mars Hydro, because they’re cheap to run and made plants grow like weeds.
Can I use normal LED lights instead of grow lights?
I have a whole article about this, linked in the first paragraph of this article, but here’s a tl;dr:
LED grow lights produce energy that plants can absorb, just not nearly as much as a grow light.
Therefore, if you have a spot in your home that has a bit of light, but not a tonne, a normal LED bulb can boost that light enough to keep a plant there.
There wouldn’t be enough light for something like a cactus, but you could keep a fern or peace lily. For best results, put the light on a timer from, say, 4 – 11 so you don’t need to remember to turn it on.
How to use grow lights
There is too much variance in our homes to give a definitive answer to this, plus different plants have different needs.
It’s usually advised to keep grow lights on for 12 hours a day BUT that doesn’t take into account any light the plants already get. If your plants get some light for some of the day, you won’t need the grow lights on. Rather than having them on 9-9, 4-9 may be fine.
Also, that’s for optimum growth. You might just want a bit of growth. Play around with it.
There’s also no hard and fast rule for how close your plant has to be to the grow light. My Rhapidophora was about 2 feet away and they made a massive difference. Again, play around with placement until you find what your plants like OR shift them around when you’re watering.
One caveat of using normal LED lights as grow lights is that the plant needs to be as close to the light source as possible for it to have any effect.
If you have any questions, feel free to leave me a comment!