Grow Like a Pro With This Simple DIY Grow Light Setup for Seedlings


You want to start plants from seed, and you want it to be easy.

So, you get out some pots, fill them with potting soil, plant your seeds, and water them.

As you place the pots in a sunny window, you look down at them with a satisfied nod.

Even though it seems like an easy way to start seeds – it’s nearly impossible to grow healthy seedlings in front of a window, especially during winter and spring when the days are short, and the sun is weak.

Seedlings need 12-16 hours of strong, overhead light.

And what happens when they don’t get it?

They struggle.

They become spindly, stretched out, and flop over. And that’s a bad thing.

Healthy seedlings are strong, short, and stocky.

They’re much more likely to withstand everything Mother Nature will throw at them.

And growing your seedlings under lights is the best way to make sure they’ll thrive when you set them outside. A proper grow light setup will prevent leggy seedlings.

I’ve been gardening for more than 20 years, and after a lot of trial and error, I have my seed starting system down to a fine art.

And it all starts with the right seed starting setup for seedlings.

Keep reading to discover how easy it is to create your own DIY grow light stand – no carpentry required!

BONUS: As a bonus for joining my weekly newsletter, download a free set of indoor seed starting setup plans and get your grow light assembled in an afternoon. It’s the best way to grow healthy seedlings this year and every year!

This post may contain affiliate links which means I’ll get a small commission if you make a purchase after clicking one of my links. I only link to products I use and recommend.

lettuce seedlings under a grow light
To grow healthy seedlings indoors, they need plenty of artificial light.

Choose adjustable shelves for your DIY grow light stand

I recommend using adjustable wire shelves (with wheels) for your grow light shelves.

What I love about these shelf units:

  • They’re sturdy.
  • They’re easy to assemble. They only take about 30 minutes to put together and the only tool you’ll need is a rubber mallet.
  • You can adjust the shelves if you change your mind later.
  • They’re easy to move because they have wheels.
  • You can fit up to four 10″ x 20″ trays on each shelf!
  • When you’re not starting seeds on them, you can use them for storage or as a drying rack for herbs or a curing rack for garlic and onions.

The first thing to decide is how deep of a shelf unit to purchase.

You have two choices, 1.5′ deep, or 2′ deep.

If you have the floor space and budget for the 2′ deep shelves and lights, they’re the better investment because you’ll get more light coverage on your seedlings.

Wire shelf unit: 1.5′ x 4′ x 6′

  • Pros: Less expensive and has a small footprint.
  • Cons: Because the lights that fit this shelf don’t fully cover a 10″ x 20″ tray, the seedlings on the ends of the flat can get a little leggy.
    • Plan to spin your trays regularly, so they get more evenly lit.
    • This setup also works best when you can place the shelves next to a wall that you’ve covered with mylar – this helps to bounce more light back onto the seedlings. If you can’t put your stand next to a wall, choose the 2′ x 4′ shelves.
    • The other thing you can do is put only two trays on each shelf, end-to-end, but this cuts the number of seedlings you can grow in half!

Wire shelf unit: 2′ x 4′ x 6′

  • Pros: Even light for your seedlings. The 6-tube lights you’ll use with this setup give excellent light coverage for 10 x 20″ trays.
  • Cons: The shelves take up more floor space, and the shelves and lights are more expensive.

Related: What’s the difference between seeds and seedlings?

Shop for supplies: Shelf unit

Prices last updated on 2022-08-16 at 10:29

Use the best seed starting grow lights for your DIY grow light stand

Once you’ve chosen your shelve unit, the next thing to do is choose your indoor grow lights.

I recommend fluorescent grow lights from Hydrofarm. They’re reliable, relatively inexpensive, and use fluorescent bulbs.

I’ve used them for years and have always been happy with them. They’re my favorite grow light for starting seeds indoors.

And they have a “designer” series, which has a bronze finish if you don’t like the look of the white fixtures. 

LED grow lights are another option, but be aware that you generally need to keep LED lights very far away from the tops of your plants (20 inches or more), which means your grow light setup will take up a lot more floor space.

If you choose to use a shop light, make sure to choose a full-spectrum fluorescent bulb that puts out enough lumens for your indoor plants.

Here’s how to make it easy to grow healthy seedlings every year: download my FREE grow light plans.

The size of fluorescent light you choose depends on the shelving unit you’re using.

  • The 4-bulb fixtures fit the 1.5′ x 4′ shelves.
  • The 6-bulb fixtures fit the 2′ x 4′ shelves.
  • But if you hang one light from the ceiling, and use the top shelf for growing plants, you can use one 6-bulb fixture with the 1.5′ x 4′ shelf unit.

Another option is to use two 2′ x 2′ fixtures on one shelf. This gives you more flexibility.

  • You can start 2 flats under one light, and not have to turn an entire 4′ fixture on.
  • Or start flats at very different times and raise and lower the heights of the two lights independently.

Shop for supplies. Best grow lights: 4-bulb lights (fit the 1.5′ x 4′ shelves)

Prices last updated on 2022-08-16 at 10:29

Shop for supplies. Best grow lights: 6-bulb lights (fit the 2′ x 4′ shelves)

Sale
Hydrofarm Agrobrite FLT46 T5 System, 4 Feet, 6 Tube Fluorescent Grow Light, 1 Count (Pack of 1), White
  • Dual On/Off switches allow you to control the amount of lumens as needed
  • Includes 120V 10ft grounded power cord
Sale
Hydrofarm Agrobrite Flp46, 4' Fixture with Lamps, 4 Foot, Black
  • 2 3/8”H x 18.5"W x 46.25"L
  • Includes 10' grounded power cord

Prices last updated on 2022-08-16 at 05:19

Must-have accessories for your grow light shelves

Hang the lights with adjustable light hangers

An adjustable grow light stand is a must so you can move your lights up as your plants grow.

And you need a secure way to hang your lights on the grow shelf. The best tool for the job is ratchet hangers that are designed to suspend plant lights.

They’re easy to use and will support the weight of heavy lights.

A common alternative is to use chain and S hooks, but these can be finicky and require you to unhook the light to move the light up or down, which is just asking for trouble. You don’t want one slip of the finger to destroy all your hard work!

These ratchet hangers make raising and lowering the lights a pleasure rather than a chore.

You’ll need one pair per light fixture.

Growsun 2 Pair of 1/8 inch Adjustable Grow Light Hangers Rope Hanger Ratchet for Growing Tent
  • Rope Material - Braided Polypropylen. Hook Material - Zinc Plated Steel
  • Rope Length -8 Feet. 4 easy-to-use carabiner clips

Prices last updated on 2022-08-16 at 05:19

Set up an oscillating fan for each shelf

Besides growing your seedlings under lights, the other critical item that’ll ensure you grow healthy seedlings is an oscillating fan.

I can’t stress enough how important air movement is for seedling health!

An inexpensive oscillating fan pointed at each of your shelves will cut down on diseases like damping off and make your seedlings stockier and sturdier.

The type of fan you should use depends on your setup.

I have a second set of shelves across from my plants that I clamp my fans to and point directly at the plants.

You could also set a tabletop fan on a shelf unit that’s next to your grow light stand.

You may need to get creative if you don’t have anywhere to set a fan.

  • One thing you could do would be to clamp a small fan on one side of each shelf and sacrifice some space for the fan.
  • Another idea is to get a long tension rod that is long enough to go from floor to ceiling, and clamp fans to it.

You’ll need one fan per shelf.

Could you use a FREE set of plans so you can set up your seed starting rack in an afternoon? Click here to download them now.

Shop for fans

10000mAh Battery Operated Clip On Fan with Hanging Hook, Super Strong Airflow, 4 Speeds, Sturdy Clamp, Timer, for Desktop Tent Treadmill Golf Cart Hurricane Camping
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Comfort Zone CZ6C 6-inch Quiet Portable Indoor 2-Speed Desk Fan with Clip and Fully Adjustable Tilt, White
  • CLIP-ON | Easily Clips on to any Surface with a Strong Clamp
  • DURABLE | Tough Break Resistant ABS Plastic Blades
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Lasko 1885 18" Cyclone Pedestal Fan with Remote Control, 18 inches White
  • BEAT THE HEAT – If you live in the heat with no central air or your window AC units do a poor job of...
  • VERY POWERFUL – Powered by 3 energy-efficient speeds, this 5 blade fan with premium grade electric...

Prices last updated on 2022-08-16 at 05:19

Plug your lights and fans into a heavy-duty timer

Since your plants need some darkness each day, you’ll need to set your light(s) on a timer.

You’ll also want to put your fan(s) on a separate timer.

BN-LINK 7 Day Heavy Duty Digital Programmable Timer, FD60 U6, 115V, 60Hz, Dual Outlet, Indoor, for Lamp Light Fan Security UL Listed
  • ✓ VERSATILE & CUSTOMIZABLE: Easily set up to 8 on/off programs for the timer’s two grounded outlets....
  • ✓ JUST SET & GO: Choose your own individual days or simply select one of the convenient pre-set...

Prices last updated on 2022-08-16 at 05:19

Related: Find the best seed companies online.

Plug everything into a surge suppressor

You’ll also want to protect all of your seed-starting equipment from electrical surges.

A surge suppressor is a good insurance policy against losing all of your equipment because of some weird power spike.

Sale
Tripp Lite 8 Outlet Surge Protector Power Strip, 8ft Cord Right Angle Plug, LIFETIME INSURANCE & $75K INSURANCE (TLP808) light gray
  • Protect Any Electronic Device From Power Surges & Spikes:Surge Protector with eight outlets and protects...
  • PREMIUM SURGE PROTECTION WITH LONG POWER CORD: This surge suppressor provides eight total NEMA 5-15R...

Prices last updated on 2022-08-16 at 05:39

Consider using a heat mat

A heat mat is optional but will help your seeds germinate faster.

  • Unless you plan to start hundreds of plants at once, one heat mat should be enough.
  • If you get a heat mat, I highly recommend getting a heat mat thermostat with it.
  • It’ll turn your mat on and off automatically and keep your soil at a more even temperature.
  • You can fit two 10″ x 20″ flats on one mat.

Shop for a heat mat & thermostats

VIVOSUN Durable Waterproof Seedling Heat Mat Warm Hydroponic Heating Pad 20" x 20.75" MET Standard
  • Reliable Results: The VIVOSUN professional heat mat maintains sweet-spot temperatures around...
  • Stable & Uniform Heat: The advanced far-infrared heating technology of this heat pad provides your plant...
Sale
VIVOSUN Digital Heat Mat Thermostat Temperature Controller 40–108 ºF for Seedlings, Germination, Rooting, Fermentation and Reptiles
  • Professional, Reliable Results: Regulates and maintains your preferred temperature within a control range...
  • High-Quality Construction: With an easy-to-grip hexagonal shape and made of an extra-fortified plastic,...

Prices last updated on 2022-08-16 at 05:19

Use mylar to reflect light back onto your plants

If you plan to put your seed-starting rack next to a wall, covering the wall with mylar is a good idea.

  • It’ll bounce light back onto your seedlings better than paint.
  • It’ll protect your wall from water splashes and dirt.
  • And, if you chose to go with the 1.5′ deep shelves, it’s helpful to bounce all the light you can back onto your plants since the 4-bulb fixtures that fit those shelves don’t provide full light coverage for your trays if you put 4 trays on a shelf.
Mylar Reflective Material, 4 Feet x 25 Feet, 2 Mil
  • 2 Mil Thick (Heavy Duty not 1mil like many on Amazon)
  • 48

Prices last updated on 2022-08-16 at 05:19

Frequently asked questions about growing seedlings indoors

tomatoes under a grow light
A grow light setup is a must if you want to grow healthy seedlings.

How many grow lights do I need per shelf?

It depends on how many square feet of seedlings you plan to put on each shelf. Seedlings need 2,000 to 3,000 lumens per square foot. Make sure your grow lights are putting out enough lumens for your seedlings. The lights I recommend put out 8,000-20,000 lumens. So, if you follow my plans, your seedlings will get the light they need.

How do I hang grow lights?

I recommend using sturdy, adjustable light hangers to hang your lights for seedlings. Attach each hanger to the underside of a shelf or to your ceiling. Be sure to leave enough height between shelves for the hangers, lights, and seedlings when you plan how far apart to place your shelves.

How much light do seedlings need?

Seedlings need 12-16 hours of light per day. When they don’t get enough, they become leggy and weakened. When it comes to seedlings, taller isn’t better! The best way to prevent leggy seedlings and grow healthy, successful plants is to use grow lights when you start seeds indoors. That way, you can be sure they get enough light.

When do I put light on germinated seeds?

Some seeds need light to germinate. So, it’s best to place your seedling trays under lights right after you plant your seeds. But if your seeds have already germinated, and they’re not under lights yet, get them under lights ASAP so they don’t get leggy.

How far should seedlings be from grow lights?

It depends on what type of lights you’re using. If you’re growing under fluorescent lights, place the lights 2-3 inches above your plants. If you’re using an LED grow light, consult the instructions from the manufacturer. Many need to be placed 12 or more inches above the seedlings.

When do I remove seedlings from grow lights?

Remove your seedlings from their grow lights 1-2 weeks before you plan to plant them. They need to be hardened off (toughened up) before you plant them. And that usually takes 1-2 weeks.

Are fluorescent lights better than LEDs?

The main benefit of using fluorescents instead of LED grow lights is that you need fewer square feet of space for your seed starting racks. You can mount more fluorescent lights on one shelf unit. This means you can grow more seedlings in a smaller footprint. And depending on how many seedlings you want to grow, one shelf unit may be enough.

How do I grow seeds without a grow light?

To grow seeds without a grow light, you’ll need to start seeds outdoors. You can start seeds in a cold frame or try winter sowing if you don’t have grow lights.

Download your free DIY grow light plans

Make sure you have everything you need to set up your seed starting shelves so you can grow successful seedlings this year and every year!

Download my FREE grow light plans and supply list as a bonus for joining my newsletter.

Here’s a sneak peek of your plans:

seed starting rack plans

Your turn: tell me about your grow light setup…

Have you grown seedlings inside under lights? How did it go?

Do you have any questions about how to DIY a grow light for your seedlings?

Leave a comment below!

Cheryl Spencer, certified gardener

Hi, I’m Cheryl.
I’m a certified gardener, bird lover, and spreadsheet enthusiast. I believe you can grow your dream garden and still have time to enjoy it. I teach online gardening courses and write articles that help you save time and money in your garden. Join my mailing list, and as a bonus, you’ll get a helpful checklist that’ll tell you what to do in your garden right now.

1 thought on “How to DIY a Seed Starting Rack With a Grow Light”

  1. William k. Arner

    Good share Cheryl. Thanks for it. Can you please tell me how long should I keep my plants under grow lights?

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