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plant, prune, and harvest.

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The Most Important Thing You Need to Grow Strong, Healthy Seedlings (Grow Light DIY)

Cheryl Spencer from Simply Smart Gardening
Inside: Inside: Grow light DIY instructions.


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 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 grow-light stand.

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 printable grow light plans. 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. I only link to products I use and recommend.

How to Set Up an Adjustable Grow Light Stand

  1. Choose a set of adjustable shelves.
  2. Find the right lights for your shelf unit.
  3. Decide what accessories you’ll need.
  4. Assemble your shelves.
  5. Hang the lights.
  6. Program your automatic timers.
Bonus: As a bonus for joining my weekly newsletter, download free grow light plans. You’ll be sure to grow healthy seedlings this year and every year!

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, it’s 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.

Shop for supplies: Shelf unit

Best Seed Starting Grow Lights for Your DIY Grow Light Stand

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

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

I’ve used them for years and have always been happy with them. They’re the best grow lights for seedlings.

They also 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.

The size light(s) 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 to grow 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)

Hydrofarm FLT44 System 4' Fluorescent Grow Light, 4-Feet, White
  • 3"H x 13.5"W x 46"L
  • Includes 10' grounded power cord
  • Includes 4 6400K T5 Tubes
Sale
Hydrofarm Agrobrite FLT24 T5 Fluorescent, 2 Foot, 4 Tube Grow Light System, 2-Feet, Black
  • 3"H x 13.5"W x 23"L
  • Includes 8' grounded power cord
  • Includes 4 6400K T5 Tubes
Hydrofarm Agrobrite Designer T5, FLP24, 96W 2 Foot, 4-Tube Fixture with Lamps, Black
  • 2 3/8”H x 13"W x 23.25"L
  • Includes 10' grounded power cord
  • Includes 4 6400K T5 Tubes

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, White
  • Dual On/Off switches allow you to control the amount of lumens as needed
  • Includes 120V 10ft grounded power cord
  • Hangs 3 ways - overhead, vertical, or horizontal
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
  • Includes 6 6400K T5 Tubes

Accessories for Your Grow Light Shelves

Adjustable light hangers

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
  • Up to 75-pound weight load capacity per ratchet; a pair can handle about 150-pounds

Oscillating fan(s)

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 plant 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 to 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.

Shop for fans

Holmes HAOF90NUC Blizzard 9-Inch Three-Speed Oscillating Table/Wall Fan Charcoal
  • Sold as 1 Each.
  • Smooth flowing, consistent oscillation from any position.
  • Powerful grille and shroud design maximizes air flow.
VIVOSUN 2-Pack 6 Inch Clip on Oscillating Fan Fit for 0.59 to 1 Inch Grow Tent Pole with 2-Speed Control
  • SPECIALIZED DESIGN: Great fan is specifically made to be connected to the poles in the tent so they...
  • CIRCULATES FRESH AIR: Triple spiral fan blades are angled to deliver efficient airflow with high and low...
  • QUIET, SECURE UNIT: Sturdy, lightweight mesh exterior protects the fan blades and the fan’s...
Comfort Zone CZ6C 6-inch Quiet Portable Indoor 2-Speed Desk Fan with Clip and Fully Adjustable Tilt, White
  • 2 SPEED FAN OPERATION: There are 2 convenient speed settings to choose from on this fan to help optimize...
  • ADJUSTABLE AIRFLOW: The 2-speed desk fan rotates 360 degrees, and the adjustable tilt function lets you...
  • CONVENIENT CLIP-ON DESIGN: This small desk fan for work is equipped with a strong clamp that firmly...
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...
  • EASY TO ASSEMBLE & USE – No tools required. Assembles in minutes. Just as easy to take apart to clean....

Heavy-duty timers

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, Packaging May Vary 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...
  • ✓ PROTECT YOUR HOME: Activate the “Random” Vacation mode to randomize your programmed lights. Make...

Surge suppressor(s)

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.

Tripp Lite 8 Outlet Surge Protector Power Strip, 8ft Cord Right Angle Plug, LIFETIME INSURANCE & $75K INSURANCE (TLP808)
  • 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...
  • SAFETY FIRST HIGH JOULE-RATING - CONFORMS TO UL 1449 SAFETY STANDARDS: Automatic shutoff cuts power to...

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 an 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" MET Standard
  • RELIABLE RESULTS: VIVOSUN’s professional heat mat maintains temperatures in the sweet spot of around...
  • STABLE, UNIFORM HEAT: VIVOSUN's strengthened heating film ensure this durable mat never scorches your...
  • BUILT TO LAST: Supple, flexible and ultra-durable, VIVOSUN goes beyond stringent MET standards,...
VIVOSUN Digital Heat Mat Thermostat Temperature Controller 40–108 ºF for Seedlings, Germination, Rooting, Fermentation and Reptiles
  • PROFESSIONAL RELIABILITY AND RESULTS: Regulates and maintains your preferred temperature within a control...
  • HIGH-QUALITY CONSTRUCTION: With an easy-to-grip hexagonal shape and made of an extra-fortified plastic,...
  • ZERO-EFFORT SET UP & OPERATION: The controller comes with a manual but you won’t need to read it! Using...

Mylar

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.
Earth Start Reflective Mylar Roll 25 Feet Long, 2 Mil Thick
  • 2 Mil Thick (Heavy Duty not 1mil like many on Amazon)
  • 48
  • 100% Light Tight

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 healthy seedlings this year and every year!

Click to download a free set of printable grow light stand plans.

Here’s a sneak peek of your plans:

 

Bonus: As a bonus for joining my weekly newsletter, download free grow light plans. You’ll be sure to grow healthy seedlings this year and every year!

Your turn: Tell me about your grow light rack…

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

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

Leave a comment below!

Hi! I’m Cheryl.

I believe you can grow your dream garden and still have time to enjoy it.

I’ll show you how easy it can be to have a garden that fits into your lifestyle, wows your neighbors, and makes your family say “more veggies, please!”

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.

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