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Yes, plants can grow under normal LED lights, but not as well as they could under grow lights.
Grow lights aren’t special – they’re just strong. They cram a lot of LEDs onto one unit. If you have a strong light close to your plant, it can help it grow, despite not being marketed as a grow light.
Normal LED lights do need to be close to your plants though – the closer the better (without them burning). Preferably about a foot away.
When grow lights are made, the manufacturers measure the PAR (photosynthetically active radiation), which is the type of light plants use to photosynthesise.
Normal LED lights tend to have their brightness measured in lumens, lux, or footcandles, which are all ways of measuring light that humans can see.
It makes sense because we’re buying them for the purpose of providing us with visible light BUT it’s not the right type of light for houseplants.
There are lux to PAR calculators out there, but they’re not that accurate, because different parts of light can be filtered out by different things.
What’s the difference between LED grow lights and regular LED lights?
In the layest of layman’s terms grow lights are stronger than regular house LED lights.
There’s no magical colour that they use or anything, they’re just brighter. They have more diodes and more power.
If you have very bright lights in your home that you can move close to your plants, you’ve got yourself a grow light. It doesn’t necessarily have to be marketed as such.
If your light is bright enough that it’s uncomfortable to look at, it’ll be able to sustain a plant.
But what’s the difference in terms of specs? My MarsHydro Growlight has over 20k lumens (I think, It’s not easy to find that info). A powerful LED light has, er, 2600.
2600 lumens is also very high for a lightbulb. 450 is more usual.
Can I put grow lights in my overhead light fittings?
Overhead light fittings are typically too far away from your plants to make any real difference to your plants – whether you use a bulb marketed as a grow light or just a strong, regular LED bulb.
My favourite ever Facebook post was a girl asking if she could simply put a grow light in her overhead light fitting and be done for the day. When someone replied saying it was too far away she replied IN ALL SERIOUSNESS 'but the sun is really far away'. I know, but the sun is also REALLY freaking hot. And literally a great big nuclear reactor. So yeah, no, putting grow bulbs in your big light isn't worth it.
Putting grow bulbs in lamps, however, is a great shout.
By the way, if you have a super powerful grow light, keeping it high above your plants and running it for about 14 hours a day can provide a high volume of light, which is what they need – not intensity, but volume. Grow bulbs aren’t powerful enough to have any impact at a distance.
Why would I need extra lights to grow plants?
It’s absolutely NOT required that you purchase extra lights for your plants.
But it can be an easy way to help your plants out, especially in winter.
Here in the UK, we’re quite a way away from the equator. The sun is even farther (by quite a long way, but we won’t get into that). Stitch that with the fact that we have a layer of brick and glass between the sun and our plants and you can understand why our plants don’t quite grow as lush as they might in their natural environment.
You don’t need grow lights, but a plant getting the correct light can not only help it grow better, but it’ll help it grow stronger, and be more able to fight off pests and diseases.
Why might you want grow lights?
You have a dark corner you’ll like to add plants to
I have a dingy corner in the back of my living room – I equipped it with a bookcase (the Fjallbo from Ikea if you’re interested) and a set of cheap grow lights (I use these ones from Amazon). Whilst it’s still too dark to have any bright light lovers, it’s great for my overgrown philodendrons and a few Calathea.
You live in a dark house
Some houses just don’t get that much light, and that’s ok. You can still have house plants, but be sure to choose your plant carefully (here are my picks for low-light plants).
I have a normal lamp with a normal bulb that I keep over my peace lily in winter. I don’t run it all day – just a couple of hours in the morning, and about four in the evening. Whilst it won’t provide enough light to help her grow, it will give her enough energy to not die, plus it kicks out a bit of heat.
Your plants suffer in winter
Houseplants have a hard time over winter.
They typically come from the tropics, and they don’t have winter there. Not only is there less light, but humidity is also lower and it’s colder. A couple of grow lights might just help them along a bit.
We’re just coming out of winter now, and I’m pleased to say that I didn’t lose any of my plants. I wrote this post on keeping plants alive over winter if it’s something that you’re worried about or struggling with.
Often, the light from your lamps is sufficient to keep your plants alive with having specific grow lights, but they’ll need to be close. You could also put more powerful bulbs (these ones are great) in your lamps to help out.
Bear in mind that whilst LED bulbs are more expensive than other bulbs, they typically last waaaaay longer and use less energy.
In our house we have a TONNE of extra lights – we have an Aerogarden, three aquariums, a terrarium and I run a MarsHydro 1000 grow light. It doesn’t make that much of a dent in our energy bills (we have an app that breaks down our energy usage, because of all the filters and heaters and lights etc).
Your plants need some extra tlc
It’s always a good idea to have a little hospital area or any sickly-looking plants and adding a grow light may help them to get back on their feet.
If you look at the picture above, that’s what I use my Mars Hydro growlight for, and it’s AMAZING. You’d be shocked at how quickly plants start to perk up.
You could argue that poorly plants may prefer to be in natural light, and that’s broadly true BUT you don’t want to risk burning them, chilling them (windowsills can be cold in winter), or risking any other plants on the sill.
Grow lights tend to give off warmth more than normal LED lights because they’re more powerful, which can definitely help plants, especially in winter.
If you have an old heat pad lying around (we’re forever taking in sick hedgehogs, setting up terrariums etc etc, so we actually do), pair that with a normal LED light and you’ve made yourself a lovely cosy spot for a poorly plant.
Do I need specialist grow lights, or will LED lights do?
Grow lights ARE LED lights, they’re just stronger and marketed as such.
Most grow lights aren’t aimed at houseplant growers – they’re for gardeners to grow on seedlings or for people selling, er, speciality plants.
If you just want a bit of supplemental lighting, just go for something that gets good reviews. I have some lights linked on my resources page.
However, if you want to really treat your plants to some good light, and really help them grow, you want to invest in a powerful grow light – like the Mars Hydro one I mentioned, but maybe the 3000 rather than the 1000. Hang it a good few feet above your plants, and leave it on for 14ish hours a day. The combination of distance and power increases the light volume to the plant, which is called the daily light integral (DLI).
Which lights do I recommend?
You can absolutely use regular LED lighting, and your plants will be able to do a bit of photosynthesising from it.
For example, if you have a dim corner with a ZZ plant or a golden pothos, a snake plant, then a regular lamp will do just fine.
However, it won’t be enough to keep your plant growing, especially over winter. For that you need actual grow lights.
You can also buy grow bulbs to fit into lamps you already own. Grow bulbs can be really good, but they’re not as powerful as grow lights.
When it comes to houseplants, we’re only interested in PAR and PPFD, which measures the presence of the specific light used for photosynthesis (PAR) and the amount of that light actually hitting the leaf (PPFD).
They’re not easy or cheap to measure. Most cheap light meters measure lumens, lux or foot candles, which measure visible light. Since plants can’t see, it doesn’t really matter how many lumens lights produce.
Do I definitely need artificial lights to grow healthy houseplants?
Noooo, but houses vary a lot, as do the parts of the world where you live. Grow lights enable you to grow plants (rather than just have them survive) in parts of your house that they otherwise couldn’t. They can really help to brighten up weird dark corners and recesses.
When should I invest in grow lights for my houseplants?
Grow lights can really help beginners because they take the guesswork out of knowing where to put plants. Most plants thrive under grow lights, because it’s more controlled than the sun – they get a tonne of energy but won’t burn (unless they’re super close).
If you don’t want to spend the money, they’re NOT a necessity, but in my opinion, they can be a gamechanger, even if you just use them to rehab the saddos.
In conclusion, you can use normal LED lights to boost the light going to your houseplants, but it likely won’t be strong enough to help them grow. It could save them from declining over the winter months though.