If you are starting more than one tray, buy linkable strip lights and hang them two to six inches above the leaves. Four 4 foot strips across a wire shelf cost less than one decent panel, spread light evenly over two or three flats, and sit close enough to keep seedlings short. That is the whole answer for most people, and the rest of this post is about the cases where it is wrong.
The cases where it is wrong are real. If you want one fixture instead of four, or you intend to keep herbs and peppers going under lights through the winter, a dimmable panel earns its price. If you are starting a single tray of lettuce in March, a grow bulb in a clamp lamp is genuinely enough, and anyone who tells you otherwise is selling something.
| Pick | Best for | Price | Link |
|---|---|---|---|
| Barrina T5 Grow Light Strips (4 ft) Best overall | A full shelf of two to three 1020 trays | $$ | Check price |
| VIVOSUN VS1000 LED Grow Light Best single panel | One shelf, two trays, with room to grow plants on | $$ | Check price |
| Spider Farmer SF1000 LED Grow Light Best if you grow on | Seedlings now, herbs and peppers under lights all winter | $$$ | Check price |
| GE Grow Light LED BR30 Bulb Cheapest thing that works | A single tray, a windowsill top up, or testing whether you like this | $ | Check price |
| Gardener's Supply SunLite 3-Tier Grow Light Garden Best all in one | Anyone who does not want to assemble a shelf and a lighting rig | $$$ | Check price |
Price tiers above are relative, not prices: $ is the cheapest tier here, $$$ the most expensive. Check the current listing before you buy, because lighting prices move constantly.
Why the sunny window fails in February
The window advice survives because it is true in May and nobody rechecks it in February.
Work back from your last frost and you can see the problem. In zone 6a the last frost lands around April 20, so onions go under lights in the first week of February and peppers around February 22, with tomatoes following on March 1. In zone 4a the same jobs shift to late February and the middle of March. Either way, the seedlings that matter most are sitting on your windowsill during the darkest stretch of the year that you are still gardening in.
In mid February across the northern half of the country the day is roughly ten and a half hours long, and a large share of those days are overcast. The sun is low, so light comes through the glass at a shallow angle, and a window only ever faces one direction, so the plants get a few hours of direct sun at best and lean hard into it the rest of the time.
The result is predictable: long pale stems, small leaves, and seedlings that flop over when you brush them. A stretched seedling never fully recovers. It transplants poorly, snaps in wind, and fruits later than a stocky one started at the same time.
Find your start dates first
Everything about a light setup follows from how many weeks your seedlings live indoors, and that follows from your last frost date.
Enter your US ZIP code for your USDA zone, frost dates & planting calendar.
If you are new to the zone system, USDA planting zones explained covers what the number does and does not tell you.
The three formats, and who each one is for
Shop light style LED strips
Thin linkable bars, usually 2 or 4 feet long, that mount flat under a shelf and chain together on one plug. They are the format commercial propagation has used for decades, first as fluorescent tubes and now as LED.
Their advantage is geometry, not power. Light spreads out and gets weaker fast with distance, so a modest fixture two inches from the leaves delivers more usable light to a seedling than a strong one two feet away. Strips let you park the light right on top of the crop and keep it there, raising the chain a link at a time as the plants grow.
They are the right buy for anyone starting two or more trays.
Panels
The square or rectangular fixtures sold as grow lights: one board of diodes, a hanging kit, and usually a dimmer. They are designed to hang well above the canopy and cover a defined footprint, typically around two feet square for the small ones.
The catch on a seed starting shelf is clearance. Wire shelving tiers are often too short to give a panel the distance it wants, and crowding a panel down close puts a bright hot circle in the middle of your flat and shade at the corners.
Buy a panel if you have vertical room, want one fixture instead of four, or plan to grow something on past transplant size.
Clip lights and grow bulbs
A grow bulb in a clamp lamp, or a gooseneck clip light. Cheap, instant, no installation.
The honest limit is coverage: one of these lights roughly one tray, unevenly, and the edge cells will always be weaker than the center. That is fine for a few pots of herbs or a single tray of lettuce started four weeks before your last frost. It is not fine for a flat of tomatoes that has to live indoors for seven weeks.
The picks
Best overall: linkable strip lights
Barrina T5 Grow Light Strips (4 ft)
Best for: A full shelf of two to three 1020 trays
Linkable low profile strips are the format that actually fits a seed starting shelf. You mount three or four of them a few inches above the flats, chain them to one plug, and light a whole tier evenly with no hot spot in the middle.
Pros
- Links end to end and side by side, so you light a shelf rather than a circle
- Sits close to the leaves without cooking them, which is what stops seedlings stretching
- Sold in multi packs, so cost per tray is the lowest of any option here
Cons
- Not dimmable
- Mounting clips and chains mean a real installation, not a lamp you set down
- Output is fine for seedlings and thin for fruiting plants
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Best single panel
VIVOSUN VS1000 LED Grow Light
Best for: One shelf, two trays, with room to grow plants on
A dimmable full spectrum panel that covers roughly a two foot square. One fixture, one hanging kit, one plug, and enough headroom that the same light carries peppers past transplant size if spring runs late.
Pros
- Dimmable, so you can back it off at germination and raise it as seedlings toughen
- One fixture instead of four strips to mount
- Enough output to grow plants on, not just to hold seedlings
Cons
- Needs 12 to 24 inches of clearance, which many wire shelving tiers do not have
- Light falls off toward the corners of a 1020 tray
- Costs more per tray than strips
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Best if you keep growing through winter
Spider Farmer SF1000 LED Grow Light
Best for: Seedlings now, herbs and peppers under lights all winter
The step up in build quality: a better driver, a dimming knob you will actually use, and the output to carry a pepper or a tray of herbs for months rather than weeks. Overkill if all you want is April transplants.
Pros
- Solid driver and passive cooling, so nothing whines or fails in year two
- Real dimming range
- Comfortable growing herbs and peppers indoors year round
Cons
- The most expensive way to light one tray of tomatoes
- Needs vertical clearance
- More light than seedlings require
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Cheapest thing that actually works
GE Grow Light LED BR30 Bulb
Best for: A single tray, a windowsill top up, or testing whether you like this
A grow bulb in a clamp lamp is the honest entry point. It will not light a shelf, but it will keep one tray of brassicas or a pot of basil compact next to a window that is not quite bright enough on its own.
Pros
- Costs less than a bag of potting mix
- Screws into any clamp lamp or desk lamp you already own
- No mounting, no hanging kit, no commitment
Cons
- Covers roughly one tray at best, and unevenly
- The clamp lamp is a second purchase
- You will outgrow it the first year you start more than a few plants
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Best all in one stand
Gardener's Supply SunLite 3-Tier Grow Light Garden
Best for: Anyone who does not want to assemble a shelf and a lighting rig
A stand, three tiers of trays and lights already sized and hung at the right height, out of the box. You pay a premium over building the same thing from a wire shelf and strip lights, and you skip an afternoon of measuring, drilling and zip tying.
Pros
- Lights are already at the correct height and rise with the plants
- Fits six trays in a small footprint
- Looks tidy enough for a living room, which matters more than gardeners admit
Cons
- Costs several times a shelf plus strips
- Fixed dimensions
- Overkill for the two trays most first year gardeners actually start
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How close to hang it, how long to run it, how much it covers
| Format | Hang above leaf tops | Hours per day | Roughly covers |
|---|---|---|---|
| Strip light, 4 ft | 2 to 6 inches | 14 to 16 | Two 1020 trays per strip run |
| Strip light, 2 ft | 2 to 6 inches | 14 to 16 | One 1020 tray |
| LED panel, small | 12 to 24 inches | 14 to 16 | Two 1020 trays |
| Grow bulb in clamp lamp | 6 to 12 inches | 14 to 16 | One tray, unevenly |
Three rules matter more than the numbers.
Measure from the leaves, not the soil. The gap you care about closes as the plants grow, so a light set at the right height on sowing day is too far away ten days later and too close ten days after that. Check it weekly and move the light, not the tray.
Let the seedlings tell you. Stretching, leaning and pale color mean too little light or too much distance. Bleached, cupped or crisping top leaves mean too close. Both are visible within a few days, which makes this a fast feedback loop.
Use a timer. Fourteen to sixteen hours, same schedule every day. A five dollar outlet timer removes the single most common failure in indoor seed starting, which is a gardener who forgets.
Ignore the spec sheet
Grow light listings are the worst specification writing in gardening. Wattage figures sometimes describe what the fixture draws and sometimes describe what an equivalent old fixture drew. Coverage areas are often quoted for flowering, for seedlings, and for a tent with reflective walls, all in the same listing, without saying which is which. Lumens measure brightness to a human eye, which is not the same thing as light a plant can use.
Two questions cut through all of it. What footprint does this fixture cover, and can I get it to the height it needs over my shelf? If the answers work, the seedlings will tell you within two weeks whether the fixture is adequate, and no number on the box predicts that better than they do.
The one specification worth paying for is the driver, the box or brick that converts household current for the diodes. It is the part that fails, and it is the difference between a fixture that is still running in five years and one that starts flickering in the second spring.
When not to buy one at all
Skip the light if you are direct sowing everything. Beans, peas, carrots, beets, radishes, corn and squash go straight into the ground in most zones, and a light does nothing for them.
Skip it if you are starting one tray in a long season zone. In zone 8a tomatoes go under cover around February 3 and outside in late March, and a bright window in a warm room gets a small number of plants there, especially if you can move them outdoors on mild afternoons.
Skip it if you have not yet bought trays and a decent seed starting mix. Light is the third purchase, not the first. The tier by tier list of what to buy and what to ignore is in seed starting setup: what you actually need.
And do not buy a light to fix a heat problem. Peppers and tomatoes germinate on warmth, not brightness, and a tray sitting at 60 degrees will sulk under any fixture you hang over it. Warmth gets the seed up. Light is what keeps it short once it is up.