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How to Build a Grow Rack for Seedlings

At some point in your gardening career you either have or will come to a point where you want to learn how to grow from seeds.  Building a grow rack is a common first step because having a dedicated setup to grow your new plant starts will significantly help in the quality of your starts.  This is not a necessary step, but will go far to avoid leggy, weak seedlings.

The Shelf
Before I show you the rack that I built, I would like to say this is FAR easier using a purchased shelf unit.  In fact, I had initially set up one, but we moved and the hardware for the shelf unit got lost, so I had to build a frame from scrap lumber to accommodate my shelves.  If you do decide to purchase a shelf, make sure you buy one that is wide enough for your lights.  It is best to have one that is waterproof or water-resistant.  Metal wire racks do have the benefit of being completely waterproof, though the wooden shelves are nice because they provide extra heat insulation.  I recommend looking at thrift stores or Craigslist for good candidates, or you can also buy them at Costco or hardware stores.

The Lights
The lights you use can vary.  I personally use regular cheapie shop lights that are 4 feet wide, with a random combination of warm white, cool white and daylight spectrum fluorescent bulbs.  I like them because they are cheap, readily available, and they do the job.  I put two shop lights on each shelf for the maximum amount of light for starting my seedlings.  I said it before, and I will say it again – do not waste your money on expensive “grow lights.”  The regular fluorescent bulbs will work just fine and there is no need to blow all your cash on fancy lights.

Okay, on to the rack.  So when I first set up my grow rack, I had bought a nice shelf unit at Costco that had 5 shelves and was 4 feet wide.  It worked perfectly, but somehow the parts themselves got separated from the shelves when we moved, so I had to build my own frame.  I have to admit I don’t usually measure things or plan them out when I build, so I did sort of just throw this together.  Here’s what I did:

First step – something I hadn’t gotten around to yet, was to install hooks in the shelf for the shop lights.  This will allow you to suspend your lights from the chains they (usually) come with and you can adjust the height.

how to grow from seeds


Next step – build the rack!  I cut pieces of scrap lumber we had around here to fit the shelves.  Basically, 4 legs, 2 supports for each shelf, and 4 cross-pieces for stability.


I put it all together with some basic deck screws.  Some of the lumber is pretty imperfect, which is fine.  I am very much a “Function over Form” kinda gal.  I did make one big mistake with this – I measured according to the shelf size, without considering or remembering that the lights themselves were a little longer than the shelves.  In last year’s shelf it didn’t matter because the sides were open and the lights extended past them a bit, but being made from lumber, I should have made the rack a bit wider or made the legs attached to the long sides instead of the short sides.  So, make sure you measure according to your lights!

how to grow from seeds - build a grow rack


A couple things of note:  I didn’t put that much space between the shelves because I am only going to use this one for germinating seedlings.  Either way, though, the middle shelf is removable so if I wanted to, I could have taller plants in it.  That is another benefit to having a shelf unit with removable shelves, because you can accommodate the taller plants if you like to start them early.  More flexibility in something like is definitely a good thing.

Here’s the complete shelf with the lights hooked in!

how to grow from seeds - build a grow rack

I have two shop lights on each level, and the shelf is set on a table so I can use the lower part.  You can’t see it in the picture, but the lights are simply suspended with the chains that they came with.  These chains have hooks on both ends and so one end is hooked into the light top itself and one end onto the hook I installed on the bottom of the shelf as pictured above.

If you notice my lights are crooked… well, I had to jury-rig them a bit because the lights were too wide to fit by just a tad bit.  They fit okay once I got them arranged diagonally.

And here is the last step – wrap the whole shebang in mylar space blankets

Now, why on earth would we do that?  To help trap in the heat!  Many vegetable starts are started way before the last frost and if you are like me, your only space to do so is in an unheated basement/garage/storage area!  So it really helps to do anything to help trap the heat.  The fluorescent bulbs will put off a little heat and the mylar space blankets do a very effective job at trapping it in so your seeds feel nice and warm, and decide they need to germinate.  In this picture, I’ve used two space blankets, although I used more for the full-size rack (naturally!).  I put one around the back, taped it to the top of the shelf, and the other one is taped on the top and to the sides towards the top.  Doing it this way means I can just roll it up and throw it on top of the rack when I need to get in, and then I can put it back down and tuck it in around the sides when I’m done.

Tip:  Something that will make life a lot easier for you is to have a power strip big enough to fit all your light plugs.  Seed starting requires turning the lights off at night and it’s a lot easier to flip a switch on a power strip rather than unplugging each light individually.  If you invest in a timer, even better!

So there you have it!  That’s how I start my seeds… and it works pretty well.  In a nutshell, all you really need are some lights that can be close to the plants, something to put your planted flats/pots on, and something to help trap in the warmth.

Next post in this series: Making a DIY Seed Warming Mat.


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7 Responses to "How to Build a Grow Rack for Seedlings"

  1. Dear Bethany
    We retire soon and planning to grow indigenous tree species on quite a large scale.This however is new to us and have litte knowledge on anything big lol. Wat ons bedoel is dat ons het n plan nodig om groot saai laaie te bou wat ongeveer 4 tot 5000 sade kan vat.Ons weet egter nie wat sal n goedkoop manier wees om sulke laaie te bou nie kan jy dalk iets voorstel ons is tans in Nelspruit maar beweeg na hoedspruit einde februarie 2012
    Laurent en Ilsa Changuion

    1. Marie says:

      Hello Laurent en Ilsa! This is Marie responding for Bethany. You are our first readers in South Africa that we know of!

      From the translation I am not sure if you are asking about the seed trays with soil in them, or the shelves for the trays to sit on? Here in the U.S. we can purchase plastic trays or build wood ones. The least expensive shelving is usually metal, or wood if you can build them yourself.

      Does that help? Please let us know if you have any other questions. We would like to hear how your project comes along.

      Marie and Bethany

      [Lees jy Engels? Translator Engels to Afrikaans]

      Dit is Marie reageer vir Bethany. Jy is ons eerste lesers in Suid-Afrika wat ons ken!

      Van die vertaling Ek is nie seker as jy vra oor die saailaaie met grond in hulle, of die rakke vir die bak om op te sit? Hier in die VSA, kan ons plastiek bak koop of bou van hout kinders. Die minste duur rakke is gewoonlik metaal, of hout as jy dit self kan bou

      Beteken dit help? Laat ons weet as jy enige ander vrae het. Ons wil graag hoor hoe jou projek kom.

  2. ~Mrs. R says:

    What a great seed-starting shelf! Thank you so much for posting the directions.

    Here in the Pacific Northwest something like this is ESSENTIAL, as out growing season can be quite short. Especially for those sun loving, warmth needing tomatoes!

    I even have a great metal shelving unit to use. Hmm, where to put the things I store on it… [thinking]… [thinking]… I will have to work on that one!

    I didn’t see where you keep your whole seed-starting shelving arrangement…? I was thinking in my garage… and then using a timer for the lights! When I get mine “up & running” I will let you know!
    Blessings, ~Mrs. R

    1. Bethany says:

      Yes! I’m in the Puget Sound and that’s a big reason why I wanted to do this. And I did put mine in the garage so I think you should be fine with that. I’d LOVE to hear how yours works!

  3. [...] to raise your own seedlings with an assortment of seed starting containers, heat mats, lights, grow racks, and perhaps even a cold frame or [...]

  4. I’m looking to upgrade my growing from seed setup for this year and have been thinking of making a rack like yours. This definitely helps so thanks for posting along with the pics!