The Best Grow Lights for Houseplants (and How Far Away to Hang Them)

Search “best grow light” and you get a ranked list of eight products, which is the wrong shape of answer. The right light for a single fiddle-leaf fig in a dark corner and the right light for a shelf of twelve seedlings are not the same object, and no ranking can resolve that for you.

So this guide is organised the other way round: three situations, one recommendation each, and the two numbers that decide whether any of them work.

First: do you actually need one?

Worth thirty seconds, because a grow light is often the second-best answer.

Symptoms that mean not enough light: the plant leaning hard toward the window, long bare stretches of stem between leaves, new leaves coming in smaller and paler than the old ones, steady leaf drop through winter.

If you are seeing those, try the free fix first. The brightest window in your home in January is frequently not the one you were using in July — the sun sits lower and the days are short. Moving the pot is instant and costs nothing, and our guide to winter houseplant care covers what else changes in the cold months.

A grow light is the right answer when there is no brighter window: a north-facing flat, an internal room, a shelf away from the glass, or a plant that needs more light than your best window offers.

And if you would rather not fight the problem at all, our list of low-light indoor plants is a list of plants that will not need one.

The two numbers that matter more than the product

Almost everyone gets the purchase roughly right and the setup wrong. Distance and duration do more work than the model on the box.

Distance

Iowa State University Extension is specific about this: “Fluorescent fixtures should be 6 to 12 inches from the foliage. LED can be 12 to 24 inches away in most cases.”

That difference is about heat as much as light. LEDs, in Iowa State’s words, “operate with less heat than fluorescent fixtures,” so they can sit further back without scorching anything.

Iowa State’s default LED setup is worth memorising as a baseline: a “Standard, 4-foot, plug-in shop fixture with full-spectrum (also called ‘daylight’) light, placed 18 inches from the foliage providing at least 3,000 lumens with lights on for 14 hours a day.”

Why distance matters so much: “A fixture closer to a plant would provide a greater light intensity (over a smaller area) than one placed further away.” Closer is brighter but covers less. That trade-off is the whole design problem of a plant shelf.

Duration

Twelve to fourteen hours. Iowa State: “Generally, when growing plants indoors, it is best to supply light 12 to 14 hours a day,” with an outer band of “as little as 10 hours and no more than 16 hours a day.”

More is not better. Plants respond to the length of the dark period as well as the light one — Iowa State notes that short-day plants “are more accurately referred to as ‘long-night’ plants.” Running a light around the clock is not generous, it is a different signal entirely.

The practical consequence: buy a plug timer with the light. Nobody remembers to switch a grow light on at 7am and off at 9pm for four months. The timer is the part that makes the rest of it work, and it is the cheapest thing in this guide.

	Fluorescent	LED
Distance from foliage	6–12 in	12–24 in
Hours per day	12–14	12–14
Heat	More	“Less heat than fluorescent fixtures”
Bulb replacement	“Every one to two years”	“Long-lasting”
Fades over time	Yes	“Do not fade in intensity over time”

Source: Iowa State University Extension.

Setup 1 — one or two plants: a full-spectrum bulb

Who this is for: you have a monstera in a dim corner, or two plants on a sideboard, and you do not want your living room to look like a nursery.

A full-spectrum bulb in a standard E26 socket goes into a lamp you already own. That is the entire appeal. No mounting, no new fixture, no cable to hide — you swap a bulb and point the existing lamp at the plant.

Look for: full-spectrum or “daylight” on the box, a standard fitting that matches your lamp, and the highest lumen figure you can find at a sensible price. Iowa State’s 3,000-lumen baseline is for a whole 4-foot fixture covering a shelf, so a single bulb lighting one plant does not need to match it — but brighter is genuinely better here, and cheap plant bulbs are often very dim.

Hang or aim it around 12 to 18 inches from the foliage, and put it on a timer.

Full-spectrum grow light bulbs(affiliate link, opens in a new tab)Screws into a normal lamp socket. The right starting point for one plant.

The limitation, honestly: a bulb lights a cone. One plant, maybe two if they are close together and roughly the same height. If you find yourself buying a third, you wanted a strip fixture.

Setup 2 — a shelf or a plant wall: a 4-foot LED strip fixture

Who this is for: several plants in a row, a bookcase turned into a plant shelf, a propagation station, seedlings in spring.

This is the setup Iowa State’s baseline describes, and it is the best value per plant by a wide margin. A linkable LED strip or shop fixture mounts under the shelf above, lights everything below it evenly, and disappears from view because you are looking at the shelf, not the underside of it.

Look for: a 4-foot fixture, full-spectrum or 6500K “daylight,” at least 3,000 lumens, with mounting clips or hooks included and the ability to daisy-chain units if you have more than one shelf. Barrina’s T5 strips and generic LED shop fixtures both fit this description; the specification matters more than the brand.

Mount it 18 inches above the foliage if you can. Under a fixed shelf you often cannot, which is fine — closer works, you just light a smaller footprint, so plan on the strip covering a narrower band than the shelf is deep.

LED grow light panels and strip fixtures(affiliate link, opens in a new tab)Best cost per plant once you are lighting more than two.

The limitation: it commits you to a shelf. A strip fixture in the middle of a living room wall looks like equipment, because it is.

Setup 3 — a plant that is part of the room: a pendant

Who this is for: a large statement plant in a visible space, where a shop fixture would be ugly and a bulb in a desk lamp would not reach.

Pendant grow lights are hung from the ceiling like an ordinary light fitting, in ordinary finishes, and they are designed to be looked at. Soltech’s Aspect is the best-known example of the category. You pay a substantial premium over a shop fixture for the same basic technology, and what you are buying is that it does not look like a grow light.

That is a legitimate thing to buy. A light you find ugly gets unplugged in February.

Hang it 2 to 3 feet above the plant for a large specimen — further than the shelf setup, because you are lighting a tall plant rather than a flat tray, and pendants are built for that throw.

The limitation: cost, and it needs a ceiling you can hang from. In a rental, that is often the deciding factor.

What to ignore on the box

“Purple light is more effective.” Purple LEDs emit heavily in red and blue because those are the wavelengths plants use most — Iowa State notes LED grow lights “emit only the wavelengths beneficial for plants. This high percentage of reds and blues…gives LED grow lights…a pink or purplish color.” That is real. It is also why Iowa State’s own baseline recommendation is a full-spectrum white fixture: the efficiency gain is not worth living under a purple lamp, and white full-spectrum light grows plants perfectly well.

Enormous wattage claims. Wattage is power drawn, not light delivered, and LED marketing routinely quotes an “equivalent” wattage that means nothing.

Lumens as gospel. Iowa State is careful here: “Lumens are a measure of the amount of light you see…it still does not indicate the amount of light available for the plant to use (called PAR).” Lumens are weighted to human vision, which peaks in green — the part of the spectrum plants use least. Use lumens to compare two similar fixtures, not to predict growth.

Anything promising to replace the sun. It will not. A grow light makes a dim spot workable; it does not turn a hallway into a greenhouse.

What to buy, in one paragraph

If you have one plant and a lamp, buy a full-spectrum bulb and a timer, and stop reading. If you have a shelf, buy a 4-foot full-spectrum LED strip rated at 3,000 lumens or more, mount it as close to 18 inches above the leaves as the shelf allows, and buy a timer. If the plant lives somewhere you care how the room looks, buy a pendant and accept the premium. In all three cases, set the timer to fourteen hours and then leave it alone until March.

A grow light also makes a genuinely good present for someone whose flat is darker than their ambitions — it solves a problem they have complained about rather than adding another plant to keep alive. There are more ideas in that vein in our gifts for plant lovers guide.