How to Build an Easy DIY Grow Light for Seedlings

Have you ever started your growing season with glee, only to be disappointed by spindly, weak seedlings? Don’t give up!  You might be missing one critical factor in your seed-starting process: light.  You can fix that problem by building an easy DIY grow light for seedlings.  Simple, affordable parts from your local hardware store will do the trick.

Update March 2014:  Prices have increased for some of the components of our project since last year.  We’ve updated prices in this post, but as you will see below, our DIY setup is still much less than the cost of purchasing a ready-made setup!

DIY-Grow-Light-for-Seedlings-pin

Many veggies like tomatoes and peppers need to be planted from seed 6-8 weeks before your average last frost date, putting some folks (like myself) into February and March.  

We only have about 9-10 hours of daylight in February.  Not even close to the 12-14 hours of strong, steady light required by seedlings to get a healthy start.

Here’s where our little project comes in.


The Dirt: DIY Grow Light for Seedlings

  • Cost:  About $160 for 1 shelf of lighting; additional lighting can be added later on (see costs & comparisons below)
  • Tools Required:  Rubber mallet (optional for assembling shelves)
  • Difficulty: Easy
  • Estimated Completion Time: about 30 minutes

Materials & Costs: DIY Grow Light for Seedlings

*Prices online as of 3/5/2014

Total DIY Cost

DIY Grow Light For Seedlings Costs & Materials | PetiteFarmstead.com

  • 1 shelf of lighting (6 sq ft): About $160 or $26/sq ft
  • 2 shelves of lighting (12 sq ft): $217 or $18/sq ft 
  • 3 shelves of lighting (18 sq ft): $295 or $16/sq ft 

Compare to the cost of these commercial setups:

Make the cost of your DIY Grow Light setup even less:

  • Source shelving and other components on Craigslist.org or at garage sales; or try Freecycle.org.
  • Watch for sales and coupons at Lowe’s, Home Depot, or on coupon sites like RetailMeNot.com.
  • Try visiting your local plumbing and electric store for deals on lighting and fixtures.  My local Grover Electric and Plumbing Supply had the light fixtures on sale for $10 recently!
  • Save on shipping by signing up for Amazon Prime or using the Store Pickup feature at Lowe’s, Home Depot, Sears, or other stores.

Step 1: Assemble & Install Your Shelf

Assemble your metal shelf, or if you already have one, install it where you want to grow your seedlings.  My shelf is in daylight basement next to a south-facing window.  Save the cardboard from the shelving box.  Use it to line the shelves (to keep water from dripping on the shelf below).

DIY Grow Light for Seedlings-6

Place your shelf in front of a window to get even more great sunlight.


Step 2: Assemble & Hang the Lights

Insert one cool bulb and one warm bulb in each fixture.  Hang the lights along the length of one of the shelves, parallel to one another.  Make sure the bulbs alternate warm-cool-warm-cool.

 Use the S-hooks to attach the chains to the shelf above.  Adjust the chains so they are 1-2 inches above your plants.  

DIY Grow Light for Seedlings-7

Adjust the chains on the lights so the bulbs are about 2 inches above your seedlings.


Step 3: Program Your Timer

Program your timer according to its instructions.  The lights should be on for about 14 hours per day.  I have mine set to keep the lights on from 6 AM to 8 PM, 7 days a week.  


Step 4: Plug In the Lights

Plug your lights into the surge protector.  Plug the surge protector into the timer.  Plug the timer into your extension cord/wall outlet.  

DIY Grow Light for Seedlings-11

Plug the lights into a surge protector, which plugs into the timer, which plugs into an extension cord or wall outlet.


Step 5: Watch Your Seedlings Thrive!

This is the fun part!  You’ll notice that your seedlings will no longer be spindly and weak, but stout and strong.  

Lettuce seedlings planted in a repurposed clamshell are strong and healthy about a month after being planted.

Lettuce seedlings planted in a repurposed clamshell are strong and healthy about a month after being planted.

DIY Grow Light for Seedlings-Cabbage and onion seedlings happily basking under the glow of our DIY grow light

Cabbage and onion seedlings happily basking under the glow of our DIY grow light


 I’ve since added another shelf of lights.  The other shelves are perfect for storage for my seed potatoes, watering can, and other plants awaiting warmer weather.

Here's my station about a month after construction.  I've added another shelf of lights, and remaining shelves house seed potatoes and other plants.

Here’s my station about a month after construction. I’ve added another shelf of lights, and remaining shelves house seed potatoes and other plants.

What do you think?

How do you start your seeds indoors?  Do you have a grow light for your seedlings?  

About Stacie

Stacie Humpherys is an engineer, graphic artist, and farmer who lives on her very own petite farmstead just outside of Middleton, Idaho. Say hi on Twitter.

Comments

  1. Nice tutorial!, Are those lights enough for those seedlings? It looks like they are T8 tubes but T5 tubes are more efficient and produce more light!

    • Thanks, I’ll have to take a look at T5! The T8 work great though; my seedlings ended up being very robust and did really well all through the growing season!

  2. I was happy to find this project via Pinterest. However, your calculation of the cost of this project is way, way off, especially if you plan to use all of the shelves on one of those 5-shelf wire racks (giving 4 shelves of usable space). T8 shop lights at Home Depot are around $20 apiece (no sales for us — sadness!) and if you plan to use all 4 racks that brings the cost to $160 — 2 shop lights = $40 per rack), not including the rack ($70 at Walmart) and bulbs. We also do not have a spare surge protector lying around as all ours are in use, so we had to get that, and a lamp timer. This grow lights project is cheaper than the ones sold at Gardeners Supply and the like, but not as cheap as I’d hoped when it’s all said and done. :-/

    • Hi Joelle,

      Thanks for your comment! The calculations were done last year; prices have increased since then. I’ve updated the posts with costs and suggestions for this year, and as you mentioned, the project is still much cheaper than the ones sold around the web. -Stacie x

  3. Where did you purchase your wire shelf at? I’m not able to find a good 48″ wide shelving unit for a decent price.

    • Hi Aaron, thanks for your comment! I just updated the blog post with sources and costs for each of the components. I got my shelving unit on sale at Lowe’s last year. Watch for sales and coupons; I would expect them to come out with something soon! You could also use a wooden shelving unit and simply use screw-in eyes to hang the lights. Let me know what you end up doing! -Stacie x

  4. This is my first attempt at growing a garden from seed. The packets say to plant 6-8 weeks before planting outdoors. Can I start them earlier if I will have them under the lights indoors?

    • Hi Jane,

      Yes, you can start the seeds earlier, though you might need to transplant them into a bigger pot to allow them to continue growing before you put them outdoors. Some seedlings quickly outgrow the small seed starting flats and become root bound. I did this with my tomatoes last year, and they turned out great! Good luck! – Stacie x

  5. Would I be able to continue growing these indoors, never having to plant in the ground?

    • Hi Justin, Thanks for your comment!
      Yes, you can continue growing plants indoors. Keep in mind that you’ll need to transplant to larger containers every so often, and depending on the plant, you may need to pollinate by hand in order to get vegetables. Certain plants like potatoes, carrots, and other root vegetables wouldn’t do well in containers for obvious reasons. What are you planning on growing? Best, Stacie

      • Peppers, tomatos right now. Would like to start broccoli, brussel sprouts too.

        • Peppers should do really well indoors. Tomato plants will get pretty large, but will still do well in a container. Tomatoes love really hot weather, so if you can stick them in the warmest south facing window you have, or on a patio or balcony in full sun, they should do really well in a container. Broccoli and brussels sprouts are in the same family, and they actually like cold temperatures. They do best when planted early in spring or at the end of summer/fall outdoors. Also, broccoli plants can get quite large. I’ve never tried growing plants completely indoors under the lights, but it sounds like a cool experiment! Maybe I’ll leave a few seedlings under the lights and see what happens. Let me know how yours turn out!

          • Will do and thanks you have been a great help. I plan on picking up my shelving system today.

          • This shelf is working very well. I added a third another set of lights for my tomatoes. I haven’t setup room yet outside to plant but these are still doing well at 6inches tall. I also added a foil backing to prevent light escaping.

  6. Thanks SO much for this great tutorial and advice. It’s so detailed and easy to follow. I live in a very cold climate, and every fall I wish I could keep growing things all year round. This year, even though we are expecting snow tomorrow, thanks to you, I can! It’s so nice of you to share your knowledge freely with everyone. People like you make the web great!

  7. Will this work well for African violet plants also? I do want to start growing my plants from seed each year instead of purchasing them at garden centers (where they cost much more) I have a few African violets that do not get enough sun. I have one that stopped flowering because of it. These cloudy and cold winter days are just not giving them what they need. Thanks – I have a Lowe’s right down the road from me and they have everything in stock on your list right now. I have the perfect place to put it in front of a window in my office/laundry room

    • Stacie Humpherys says:

      Hi Rita,
      I have never personally grown African Violets, but I am sure they would benefit from the extra light! 🙂 Let me know how they fare — African Violets are so lovely. 🙂 -Stacie

      • Just got back from Lowe’s with everything – sadly my husband isn’t home to help me tonight 🙁 – Setting everything up in the morning – cannot wait!!

        • Stacie Humpherys says:

          Awesome, Rita! Love your website! Please let me know how yours turns out — I hope you love it! 🙂 -Stacie

  8. I’d heard it was possible to build your own grow light system but was unsure how to do it. I’m so glad I found your website and can’t wait to get started! We are going today to price the materials needed but I will also be checking out our local Salvation Army, Goodwill and Restore store before I purchase. My goal is to have everything I need so I can start some of my seedlings in a couple weeks. Thanks for great directions!

    • Stacie Humpherys says:

      Hi Aleli! That’s awesome — let me know how your shopping goes, and how your project turns out. I’m getting ready to start some seeds this weekend! I can’t wait. Feel free to shoot me an email (via the Contact Us page) if you have any questions at all! 🙂 -Stacie

  9. Hey,
    Thanks for the step by step tutorial…. How cold was your basement? Did you use heat mats for the seedlings? Thanks,
    Kevin

    • Stacie Humpherys says:

      Hi Kevin, I’m not totally sure how cold my basement was, but I didn’t need to use heat mats. I’d guess it was between 55-60 degrees Fahrenheit, though. Good luck with your garden! -Stacie

  10. hi stacie, thanks very much for posting this! this has all the information i needed 🙂
    many thanks, roslyn

  11. Does it have to be a wire rack?

    • Stacie Humpherys says:

      Nope! You could use any kind of shelving, as long as you can hang the lights from it safely. A wooden shelf would work too; simply use screw-in eyes to fasten the s-hooks. Feel free to be creative.

  12. Thank you for the plans and product list. I used your links, ordered online from Lowes for pickup and picked it up last night. I built it myself this morning. My only issue was the S hooks. The ones on the list were too large for the chain in the fixture. So we went back this afternoon, got a smaller size and it’s perfect now. Also ordered the heat mats from Walmart. Now I’d love a similar plan/product list for raised beds and a drip irrigation system 🙂

    Thank you again!

    • Stacie Humpherys says:

      Hi Bev, so glad you found this helpful! Sorry for the hiccup with the s-hooks. I’ll edit the post to clarify that. 🙂 Thanks for the ideas! I put some raised beds out this year and so I can definitely make a post about that! 🙂

  13. Thanks for the tutorial (and the comments). I’ve tried seedlings inside during the winter, but have been wanting a grow light to get sturdier plants. I’m sure this would also be good for growing leafy greens (lettuce, spinach, etc) indoors during the winter, so I could have a constant supply.

    • Stacie Humpherys says:

      Hi Dawn, for sure! I’ve personally grown leafy greens under these lights in the winter, and they love it!

  14. Great tutorial! Thank you so much. I noticed you have some what appear to be biodegradable seedling pots? What do you use and how do you go about transplanting? I had a lot of trouble transplanting from plastic trays this year! Thanks again!

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