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Note: We’ve recently updated this article to include the latest LED grow light technology in addition to common fluorescent shop lights which can also be used as grow lights. Since this article was originally written, the price of LED grow lights has decreased significantly, making them competitive with or in some cases even less expensive than fluorescent lighting.
Get a jumpstart on the warm and cool weather growing seasons AND grow food indoors year round with this DIY grow light setup.
Video: introduction to a simple, indoor DIY grow light setup
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Our family grows a lot of organic food in our yard. By virtue of the fact that we live in Agricultural Zone 7b in Greenville, SC, we get to enjoy relatively warm/moderate temperatures throughout the year, although our winters can get quite cold (nighttime low temps have hit the single digits the past few years).
Nevertheless, we’re able to grow food indoors AND in our yard 365 days per year. Yep, the afternoon after it hit five degrees, we uncovered our low tunnel beds and harvested spinach, kale, miner’s lettuce, chickweed, and cilantro for a salad.
Gardening: An Investment Worth Making
The National Gardening Association estimates that for every $1 you invest into your garden, you get $8 back.
It’s so gratifying to get daily garden harvests like this!
We love helping people learn how to maximize their Return On Investment (ROI) in their garden, get huge yields, and do it all using organic/permaculture growing methods. Of course, organic gardening has a range of benefits that extend far beyond money, as we’ve stated elsewhere.
The highest ROI comes from the stuff you can get or use for free. For instance, most people bag and throw out their fall leaves. However, leaves are an incredible source of free nutrition that you can use to feed your beneficial soil microbes, which ultimately produces more delicious organic food for you. With a couple hours of work, you can get hundreds or even thousands of dollars in return if you use those leaves for your garden.
Some of the other high-ROI things you can do in your garden do require an initial upfront investment of cash. For us, one of the things that has made the biggest difference—and created the highest ROI—is making an indoor DIY grow light system.
Our DIY indoor grow light system. The shelves are lonely in this picture, but for most of the year, they’re full of plants and seedlings.
Three Reasons to Make Your Own DIY Grow Light System
You don’t HAVE to have a grow light system in order to have great gardening success, but it certainly helps. Here are three reasons we recommend serious/more advanced home gardeners make a DIY grow light system:
1. Get a Jumpstart On Each Growing Season
In our Ag Zone, we start our spring and summer seeds indoors in late January through February, then transplant them outdoors after the last frost date.
This gives us (and our plants) a 2-3 month head start on the warm weather growing season. Translation: we get to start harvesting much earlier and for much longer than if we were to direct sow our seeds outdoors once the weather warmed up.
Trays of fall seedlings started indoors in late July/early August under our grow lights will be transplanted outdoors in September.
The same thing is true when we start our fall/winter seeds indoors in July-August, then transplant the seedlings outdoors in September-October. Also, if you’ve ever started seeds indoors without grow lights, you might also realize how hard it is to get enough sunlight through your windows (even south-facing windows) to keep your plants from getting weak and leggy.
2. Grow Food Indoors
There are indoor grow light systems you can use to grow large plants like tomatoes, but that’s not what we’re discussing here. The grow light system we use and recommend is designed for starting seeds for transplanting OR growing smaller plants like lettuces and other greens for indoor harvests.
Using the grow light system in this article, you can easily grow enough greens and/or microgreens to get a nice daily harvest. If you live in a particularly cold climate, this benefit might be especially attractive since it’s more difficult for you to grow outdoors during the winter.
An array of colorful microgreens growing under our indoor grow light system. Microgreens aren’t just beautiful and tasty, they also pack some serious nutrition. You can read our article about how (and why) to grow microgreens here.
3. Improve Seed Germination Rates
We start a lot of seeds indoors and outdoors. No matter where you live, an outdoor growing environment is always going to be a little less “stable” than an indoor growing environment— varying temperatures, soil moisture fluctuations, etc.
You’ll use less seeds and have a higher germination rate by starting your seeds indoors under grow lights. Not to mention, there might be hungry insects that are more than happy to chew down an emergent seedling soon after it punches through the soil surface in your garden—not so when you start your seeds indoors.
No matter how many times we see it happen, we still get a sense of joy seeing seeds germinate – especially if it’s still freezing cold and dreary outside!
You can improve your seed germination rates and plant survival rates by starting your main seedlings indoors, then transplanting them outdoors once they’re 6-9 weeks old. Plus, if you have an edible landscape, more mature plants are more immediately attractive.
How To Put Together Your Own Grow Light System
The grow light system we use has the following benefits/features:
- Relatively inexpensive and can easily pay for itself in a single growing season.
- Easy to break down and set up.
- Made with parts that can be ordered from Amazon or found at large home improvement stores like Lowes or Home Depot.
- Made with parts you never have to replace (except for the lightbulbs which need to be replaced every 10,000-50,000 light hours depending on manufacturer’s recommendations or visual signs that your plants are getting inadequate levels of light).
- *Fluorescent bulbs produce 3x more light than incandescents, are energy efficient and non-heating. e.g. they’ll grow your plants without really impacting your energy or heating/cooling bills. (*Since this article was first written, the price of LED grow lights has come WAY down, so we also have LED grow light options listed below. LED grow lights are even more energy efficient than fluorescent bulbs.)
- Made with adjustable parts so you can raise or lower each row or each light, AND remove or add shelves as needed.
1. The Parts for Your Indoor DIY Grow Light System
Below are the parts you’ll need to put together the exact grow light setup we use. Note: We’re providing info for two different sized grow light setups using the same materials (option 2 is just a miniature version):
- Option 1: LARGE Grow Light System – Five shelf system (74-in H x 48-in W x 18-in D). Technically, this system has 6 shelves, but you can’t hang lights above the top shelf, so there are only five shelves to put seed flats on. This LARGE Grow Light System is ideal if you’re growing plants for a large garden/edible landscape or if you plan to start/grow hundreds of plants indoors at the same time.
- Option 2: SMALL Grow Light System – Two shelf system (30-in H x 24-in W x 14-in D). Technically, this system has 3 shelves, but you can’t hang lights above the top shelf, so there are only two shelves to put seed flats on. The SMALL Grow Light System is ideal if you’re growing in a smaller garden/edible landscape or if you only plan to start/grow less than a hundred plants indoors at the same time.
Parts you’ll need to purchase and their cost via Amazon ( *please note that prices on Amazon change, sometimes daily, depending on sales and product availability ):
Materials List for LARGE Shelf Grow Light System:
- 48″ Multi-Tier Steel Shelving Unit (48″L x 18″W x 82″H)/ there are a few product options here:
- A tall 82″ chrome-colored unit with 6 adjustable tiers and wheels – product link | cost: (*since this is the lowest cost, we’ll use it in our total costs below)
- Same tall 82″ unit as above (82″), but black-colored – product link | cost:
- A shorter 72″ high steel unit with 6 adjustable tiers and wheels – product link | cost:
- 10-Outlet Power Strip – product link | quantity needed: 1 | cost: (it’s a 2-pack)
- Open Oval Chain (black finish) – product link | quantity needed: 1 ft strips x 20 total strips | cost: (whole roll, 50′) Depending on the lights you get, you may not need the chain since chains are sometimes included with the lights.
- 20 S-hooks (can be easily adjusted with pliers) – product link | quantity needed: 20 | cost: for a 20-pack
- Zip Ties – product link | quantity needed: we used 10-12 but they come in a bag of 30 (you can never have too many zip ties around) | cost:
- LIGHTING: Choose EITHER LED OR Fluorescent Lights. LEDs may be a touch more expensive up-front, but costs are quickly coming down on them and the benefit of having healthier plants and lower energy costs probably outweighs any difference in upfront costs. IMPORTANT: Since the LEDs are hung about 24” above the plants/seedlings (versus fluorescents which can hang 2-3″ over seedlings) you can’t set up all 6 shelves. You can only use 4 shelves, three of which have plants on them. Therefore you only need 3 LED lights.
- LED Lights – These options assume 1 LED light strip per shelf. We’ve included a few options in case one is out of stock:
- 48″ 64W Full Spectrum LED Light Strip – product link | quantity needed: 3 | cost: per unit
- 48″ 60W Full Spectrum LED Light Strip – product link | quantity needed: 3 | cost: $45.99 per unit
- 4 pack – 48″ 60W Full Spectrum LED Light Strips – product link | quantity needed: 1 | cost: per unit
- Fluorescent Lights
- 48″ Fluorescent Shop Light Housing – product link | quantity needed: 10 | cost: $15.50 per unit
- 48″ COOL LIGHT Fluorescent Bulbs – two options depending on pricing and what’s in stock:
- product link | quantity needed: we used 1 cool light bulb in each housing unit, or 10 total cool light bulbs | cost: /ten-pack
- product link | quantity needed: same as above | cost: /ten-pack
- 48″ WARM LIGHT Fluorescent Bulbs – product link | quantity: same as above | cost: /ten-pack
- LED Lights – These options assume 1 LED light strip per shelf. We’ve included a few options in case one is out of stock:
- TOTAL COST: about $350 depending on current Amazon pricing
If you use fluorescent shop lights, S-hooks and chains allow you to hang your grow lights and adjust the distance between the bulbs and the plants as-needed (and as the plants grow taller).
Materials List for SMALL Grow Light System:
- 3-Tier Steel Shelving Unit (13.11 x 23.15 x 29.90 inches) – product link | cost: (*Note that the reason this unit is so much less expensive than a 5 or 6-tier shelf is that the width and depth are much smaller, so you won’t be able to put as many plant trays on it)
- 10-Outlet Power Strip – product link | quantity needed: 1 | cost: (it’s a 2-pack)
- Zip Ties – product link | quantity needed: we used 10-12 but they come in a bag of 30 (you can never have too many zip ties around) | cost:
- 24″ LED grow light unit – product link | quantity needed: *1 | cost per unit: per unit. (*As mentioned above in the large grow light setup notes, LEDs are hung higher about the seedlings/plants (24″) than fluorescent lights (2-3″), so you’ll only have one planting shelf with this smaller setup, rather than two.)
- Note: You may be able to find fluorescent shop light housing + 24″ warm and cool light fluorescent bulbs at you local Lowes or Home Depot, but those items seem to be very rare now. Plus, that setup will actually cost about twice as much as the LED setup we recommend above.
- (optional but recommended) Heavy duty shelf wheels | Note: these wheels allow you to easily move the entire grow light shelving system whenever, wherever you want – even when it’s full of seed trays. | product link (4-pack) | quantity: 1 | cost: $19.45
- TOTAL COST: About $150 before taxes
2. Getting the Proper Bulbs
If you’re getting full spectrum LED grow lights, you can skip this section. If you’re getting/using fluorescent lights, you’ll want to carefully read this section…
As you probably know, light is essential for plant health/growth. Sunlight contains ROYGBIV, the full spectrum of colors of the rainbow that we all learned about in kindergarten.
The two most critically important light spectrums are RED and BLUE light.
- Red spectrum light stimulates growth and flowering, but too much red light leads to tall, weak plants.
- Blue spectrum light regulates the proper amount and distribution of plant growth, ensuring that all parts of the plant take on the proper size, shape and density.
The color of light created by each type of fluorescent bulb is determined by its interior phosphor coating. When using fluorescent bulbs, we recommend using a combination of these two types of fluorescent bulbs:
- “Cool white” fluorescent bulbs offer Y/G/B (yellow, green, blue) spectrum lights for your plants. Cool bulbs have a kelvin range between 5000 – 6000K.
- “Warm white” provides O/R (orange, red) spectrum light. Warm bulbs have a kelvin range between 2700 – 3500K.
So, install alternating cool and warm fluorescent bulbs into your light housing as indicated in the materials list above and shown in the image below. This way, you can mimic nearly the entire color spectrum of the sun, thus growing healthy seedlings and plants.
Alternating cool and warm fluorescent shop light bulbs. The bulbs don’t actually look red or blue to the naked eye.
3. Other Indoor Grow Light FAQs
Below are answers to the most frequently asked questions we get about our DIY indoor grow light setup:
1. How much indoor light hours do your plants need?
Answer: Each type of plant is a little different, but generally speaking, your edible garden plants will do fine with 10-14 hours of indoor light per day. You can buy a timer if you want or just set an alert on your phone/calendar to remind you to turn the lights on in the morning and off at night. Just like people, plants need darkness/rest, so try not to forget to turn your lights off.
More tips: 1) Plug one power strip into the other power strip so that you can just flip a single switch to turn all the lights on or off. 2) Use zip ties to attach your power strips to the side of your shelving unit AND to keep the power chords neat and organized.
2. How close do you let your plants go to the fluorescent grow lights?
Answer: Keep your plants about 2-3″ from your fluorescent lights. If your plants start looking thin, leggy and weak, move the lights closer to the tops of your plants using your adjustable chains and S-hooks. If the leaves get scalded, move your lights higher (very unlikely to happen unless your plants are directly touching the bulb).
Tomato seedlings being started indoors in February. Notice how close the lights are to the top of the plants – we keep the lights a few inches overhead. If the lights are touching the plants, your plants may get sunburn; if they’re too far away, your plants may become weak and leggy.
3. How often do I have to replace my fluorescent bulbs?
Answer: It depends on the bulbs you buy. Each manufacturer puts the estimated “lamp life” on the specs, which are often 20,000+ light hours. After a few years, if your bulbs are still working but your seedlings seem like they’re not growing as well, you may want to consider replacing them early.
4. What about growing under LED bulbs/lights?
Growing plants under LED bulbs is a little more complicated.
- Sprouts & young seedlings – For sprouts and seedlings, you’ll want the tops of your plants to be 24-28″ overhead.
- Growth stage – After your seedlings are a few weeks old, you can lower the LED lights to 18-24″ over the top of your plants.
- Flowering/fruiting – If you’re growing plants all the way to production (ex. growing strawberries or tomatoes), you’ll want to lower your LED lights to a height of 12-18″ during this stage of development.
5. What trays, cells, etc. should I get and what starting mix should I get/make?
Answer: Since we’ve had comments and emails from this article asking what seed starting trays, etc we use, we’ll quickly provide a bit of info here, then refer you to more detailed articles/videos we’ve created on that topic:
- Trays – Because we got tired of throwing away flimsy trays after one or two growing seasons, we now prefer these extra strength trays because they’re BPA-Free, SUPER durable, and also created by a local (to us) NC farmer who needed supplies that lasted longer than the current options: 5 pack & 10 pack
- Heat mat – Essential for getting good seed germination when starting tomatoes, peppers, and other summer nightshades indoors: 48″ x 20″ heat mat & thermostat to control temps
- More info – We have three free seed starting video classes (plus a free ebook) if you want to get the answers to all your seed starting questions. Plus, we also have a detailed guide showing you how to use Ladbrooke Soil Blocks.
Thanks for the correction! We’ll edit the post now. 🙂
[…] is essential if you don’t have a really sunny sunroom or greenhouse. We constructed our own (find out how here). If you want to buy a whole kit, here’s a good […]
How do you grow tomato’s in your home? Saying I just didn’t want to grow outdoors!
Also, say ok, I want to grow outdoors but want the tomato plant to grow big and get tomato’s on it which would require self pollinating: how do I go about that?
Like the article.
Jason: This grow light setup is for seed starting – getting the plants about 6-10 weeks down the road before transplanting them outdoors. It wouldn’t grow large plants like tomatoes all the way to maturity very well because the overhead lights wouldn’t be able to get to the lower leaves of a plant that tall. There are indoor grow light systems for that sort of thing, but they’re much different than what we’ve got here.
As for pollinating tomatoes, they’re actually quite easy to pollinate since they have perfect flowers. Just wiggle the plants by hand and the flowers will self-pollinate.
Your smaller set up seems to not work with those 48″lights which are way too big. Is this an error?
Thanks Marjet! You’re correct. I just updated the article with info for 24″ fluorescent bulbs and housing units.
This is awesome and full of valuable information. Thank you!
Thanks Kristin!
I cannot find parts 2 and three of this thread. Can you please send me the link?
Kelly, we’ll be publishing a three part video class/tutorial with all of the seed starting instructions. Sorry it’s not on our blog yet!
Kelly, FYI we’ve created the article you inquired about. In fact, we decided to do a series of video classes teaching people how to start plants from seed organically. The video classes are free as is the seed starting ebook. You can check them out here: https://www.growjourney.com/video-classes-complete-guide-seed-starting-organic-gardeners/
Leggy, does that mean tall with week stems?
Sean: Yes, exactly. Due to inadequate light, the plants are stretching upward rapidly to try to reach more light/sun, which eventually causes their stems to snap and the seedling to die, if more light isn’t provided first.
When is the tray info coming – i want to purchase stuff now…
We got tired of throwing away flimsy trays at the end of each growing season, so we now prefer these because they’re BPA-Free, SUPER durable, and also created by a local (to us) NC farmer who needed supplies that lasted longer than the current options: 5-pack (http://amzn.to/2kgWXFV) / 10-pack: http://amzn.to/2jjELeU.
Two additional articles for you or anyone else interested in getting really good at seed starting:
1. Three free seed starting video classes + free ebook we recently created: https://www.growjourney.com/video-classes-complete-guide-seed-starting-organic-gardeners/
2. Detailed how-to guide on using Ladbrooke soil blockers: https://www.growjourney.com/use-ladbrooke-soil-blockers-seed-starting/
Can you please give information about the trays for this set-up?
We got tired of throwing away flimsy trays at the end of each growing season, so we now prefer these because they’re BPA-Free, SUPER durable, and also created by a local (to us) NC farmer who needed supplies that lasted longer than the current options: 5-pack (http://amzn.to/2kgWXFV) / 10-pack: http://amzn.to/2jjELeU.
Depending on the type of seed we’re growing, we use either Ladbrooke soil blocks (more advanced method), plastic cells, or biodegradable cells. IMO biodegradable cells are the easiest for beginners but they can dry out more quickly than plastic cells.
*Comment update: For you or anyone else interested, we recently published three free seed starting video classes + a free seed starting ebook: https://www.growjourney.com/video-classes-complete-guide-seed-starting-organic-gardeners/
Hope that helps!
Much appreciated. i just bought the supplies for the large setup and am excited to get it ready.
Thanks!
What are your thoughts on T8/T5/LED lights?
Ryan, I certainly don’t consider myself to be a lighting expert, but from what I’ve read, LEDs are top of the list as far as light produced, energy efficiency, and minimal heat output. T5s would come in 2nd place, T8s 3rd place. If you want to geek out a bit on that topic, here are thoughts from a gentleman who has a great deal of experience growing under various types of lights: https://www.raysace.com/t5-grow-lights-vs-led-grow-lights/
Hi GrowJourney! I want to build one of these but don’t have room in my house. What kind of success might you expect if you located this in a basement room that is not heated–I live near Raleigh NC? The room never gets too cold because of the heat above it but it’s definitely not room temperature. Would it be worth it at all? I could put in my daughter’s room but she might be peeved to sleep in a room full of plants when she comes home from college for spring break :/
Thanks! Kerry Anthony
Hi Kerry! First, you might have noticed that there’s a smaller setup that we gave instructions for too. That could give you a few more options about where to put it – and if you’re only using it for a few months a year, your daughter might be more forgiving. You could break it down and put it in the basement when it’s not in use.
However, if you do put your grow lights in the basement, your cool weather seed varieties should grow fine so long as the temps stay 40+ degrees. Note the germination temps on your seed packets as many cool weather varieties still prefer relatively warm germination temps – 60+ degrees. Where you’d probably be challenged is starting warm weather varieties (tomatoes, peppers, ground cherries, etc) as they are going to need warmth to both germinate and grow – 75+ degrees is ideal. If you have heated seedling mats you could make that work or maybe even get a small space heater and sequester that area off to keep it warmer than the surrounding room.
All things considered, it might be best to have a serious sit down conversation with your daughter and explain to her that she’ll need to learn to share her room with seedlings a couple times per year. 🙂
Can’t wait to see more Instagram photos from your summer garden & butterfly adventures!
Thank you Aaron! I took your advice and have found a spot for a smaller grow light set up. The article on this topic was SO helpful. Can’t wait to share some pictures! I started the warm weather varieties you mentioned above last night. I have expanded my “garden” areas quite a bit this year. Also helpful was your article on your father’s (i think) deer deterrent method. So far it’s working great! I have some monarchs overwintering and they will be so pleased to see that the bronze fennel survived the winter and is growing strong in the usual spot–i wonder if they remember where…
Glad to hear that! My dad will be thrilled to know that his advice was helpful. Re Monarchs on your fennel – we see a lot of Swallowtails on ours, but not a lot of Monarchs, whose larvae feed exclusively on milkweed. Do you guys have overwintering Monarch chrysalides on your fennel? That would be interesting!
Should you always use a dome
Hi David! The domes are great for keeping humidity in when you’re trying to get your seeds to germinate. However, you’ll want to take the dome off AFTER your seeds germinate otherwise you’ll likely end up with too much moisture for the seedlings, which will cause “damping off” (a fungal disease which causes your plants to wilt and die). If you don’t use a dome, you’ll need to use a spray bottle a couple times a day to keep the seeds nice and damp and/or put something else over the top to help trap moisture.
Do you reuse trays and if so, how do you sterilize so prevent or stop any disease?
Kat,
We usually rinse and solarize our trays as soon as we transplant seedlings out of them (that’s a fancy way of saying put them in the sun to burn out any possible pathogens). You can also give them a bath in hot soapy water right before using them. Some people also give them a bath in water-bleach solution. If you use things like worm casting and compost in your seed starting mix, the symbiont/beneficial microbes will also help prevent pathogenic microorganisms from over-proliferating.
Hello! When using this light system indoors should I also use heat mats for germination? Or will the light provide enough heat to start the seeds? Thanks!
Sofia: it depends. For your cool weather seed varieties (brassicas, lettuce, chicory, etc) there’s no reason to use a heat mat because their germination temperatures are relatively low. However, for things like tomatoes and eggplants whose ideal germ temp are 75-80 degrees, a heat mat will allow you to get high germination and happy, vigorous seedlings. The florescent lights really don’t emit that much heat – that’s one of the reasons they’re so energy efficient. They may add about 5 degrees to your seed trays if you keep them really low to the soil surface (2-3 inches).
Sorry if this is too much info and/or not a direct answer to your question!
Thanks for the information and quick reply! I appreciate it!
OMG fantastic…my dining room currently had a folding table with a grow light, the dining room table with above chandelier on…This would make more sense LOL
As far as we’re concerned, the whole purpose of a dining room is to be a greenhouse. 🙂
We tried to build your small set up and used the link you provided for the warm fluorescent lights, and the link brought me to Amazon, but the lights were only 22″ and not 24″ that we needed. I will be sending those lights back and ordering the right sized lights at double the price. Please consider updating your website accordingly. Thanks for all the information provided.
Thanks for letting us know about the mistake, Ryan! The original 24″ Amazon warm fluorescents we had linked stopped being offered a while back, so we switched the link to a new product which is unfortunately too small (as you found out). It’s surprisingly hard to find a 24″ warm light fluorescent (warm = 2700 – 3500k) and there are none that match those specs under regular fluorescent bulbs on Amazon. However, there is one that will work listed under aquarium bulbs that is 2700k: http://amzn.to/2p1nYf4 ($9.97/each). We’ve just updated the article with the new info. Thanks again!
If i want to primarily grow lettuce and greens for consumption year round, what trays/containers should i use? How does your light setup compare to T5s?
We especially like the trays from Bootstrap Farmer. They look like regular seed starting trays but they’re way sturdier and longer-lasting. Standard seed starting trays are pretty flimsy and will crack and have to be recycled after 1-2 seasons of use. Our Bootstrap Farmer trays take a beating but still work as well as the day we got them. That’s especially important if you’re growing indoors because you don’t want to end up with soil-stained water all over your floors. If you go to our seed starting materials page here: https://www.growjourney.com/curated-organic-gardening-products/organic-seed-starting-supplies/, I’d recommend you get two things: 1) the heavy duty Bootstrap Farmer seed starting trays (top left of the page), and 2) soil block mesh trays (farther down the page in the soil block section). The mesh trays are nice to have as inserts in your solid trays because you can lift out all the plants and soil at once without damaging them. So, for instance, if you accidentally over-water which can kill your plants, you can just lift your lettuce out dump the water left in your trays, and plop the lettuce back in the tray. Does that make sense and answer your question?
Also, you said the warm 24″ bulbs are hard to come by. I’m finding lotsof different options so i must be missing something.
Sorry for my slow response, CJ! It’s easy to find 24″ fluorescent bulbs on Amazon, but it’s hard to find WARM LIGHT fluorescent bulbs (warm = 2700 – 3500k). We pair warm and cool light bulbs in each light housing unit to make sure the plants underneath get an ideal spectrum that mimics the sun. If they don’t get a broad spectrum of light, they won’t grow well. Hopefully, Amazon has started providing more 24″ warm light fluorescents again. 🙂
I don’t have a lot of garden space outside. How would I modify the system to accommodate the mature plants?
This system is designed for seed starting, not growing large plants all the way to maturity. You could grow smaller plants like lettuce all the way to maturity with this growlight setup, but not larger plants like tomatoes. The challenge with larger plants would be getting adequate light to lower parts of the plant. You’d likely need different lights and possibly reflectors for that. Wish I could provide better recommendations here, but it’s not something I have experience with.
Have you ever found it necessary to add reflective material around the rack? I see that pretty frequently with indoor grow lights, but I don’t see that on your setup.
Dustin: nope, we have not found that necessary for growing seedlings for outdoor transplant. If we were trying to grow the plants indoors all the way to maturity, something like that might well be necessary.
This setup is to act as sunlight Right? So if I was to put small succulents under it, think it would work over the winter? I have some that I propagated this summer and I want them to have adequate sunlight over the winter!
Also about the LEDs, if you got warm and cool LEDs that were in the spectrum you mentioned, would that be considered the same?
Hi Kayla! Yes, this setup should work fine to overwinter your succulents indoors. I’m not certain if I understood the last part of your question about the LEDs, but just make sure you have a warm and cool light spectrum bulb in each housing unit so that your plants will get the spectrums of light necessary for healthy growth.
do you offer catalogs? if so i wouldlike one sent to martha wells, box 68, noorvik, AK 99763
S-hooks and chains are not listed for materials list for the smaller version. I assume they are still needed?
Sorry for the delayed response, Joseph. Your comment was accidentally screened to spam.
Actually, the reason for that omission is that the LED grow lights we recommend for the smaller setup come with connecting cords and connectors, so chains and s-hooks aren’t necessary. Hope that answers your question!
Question on you say to keep the led lights 24 -28 inches from the top of the plants but on the smaller unit the total height is only 30 inches ?
Is the distance a mistake or am I missing something
Sorry for any confusion on that point, Allen. You’re correct in that the numbers don’t add up there. Those are best practices recommendations, but you can put your LEDs closer to your seedlings and they’ll do fine – especially if you start them out closer to the LED grow lights. You wouldn’t want to give them a jolt from low to high light without a ~1 week graduated transition, for the same reason that you “harden off” your seedlings before transplanting them outdoors.
My husband built this set up for me last year and we used Daylight fluorescent bulbs instead of grow lights and were very pleased with the results.
Glad to hear you had good success with your diy grow light system, Paula! We also recommend specific types of fluorescent bulbs in this article, but provide an LED bulb option as well.
Do you need to have 2 rows of lights per shelf? What if I only wanted to do 1 set of lights per shelf?
We do, but you don’t have to. It depends on how many seed flats you plan to put on each shelf. With a single row of grow lights per shelf, you’ll only be able to do 2 flats going straight down the middle. Even then, plants on the outer edges of the flat may start getting “leggy” due to inadequate light levels. If that happens, you’ll need to start shifting the seed flats directly under the lights a couple of times each day to make sure every seedling gets enough light.
With two rows of grow lights per shelf, this isn’t a problem. In fact, during the months when we’re starting TONS of seedlings, we’ll do four seed flats per shelf, and shift each flat back and forth directly under the lights a few times each day. Hope that helps!
Worked great but the shelves were way too close together with the 6 shelves. Solution: I bought 4 legs and wheels and dismantled the three 6-shelf carts to make four. Two with 4 grow lights and two with 3. Now I can put chains on to raise and lower the lights.
Thanks Lanell! Any way you can send a picture of your revised grow light setup?
Seems that the shelf recommended for the small design (30″ tall) would only fit a single LED light and tray given that you mention LED lights need to be up to 28″ away from the plants. Would you agree?
Sorry for any confusion on that point, Dave. Re the distance between LED lights and seedlings: those are best practice recommendations, but you can put your LEDs closer to your seedlings and they’ll do fine
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If I’m using the led lights you recommend how close can they be to my mature succulent plants. Hoping they can be pretty close since they don’t get hot and there isn’t much room between the shelves. I should have read the full article before I bought this shelving. ☹️
Linda: succulents are desert plants that can take pretty intense light. While we don’t grow succulents, our garden seedlings that we start under our grow light system are VERY close to the lights – usually no more than an inch under.
I’m trying to figure out the equipment I would need for the larger setup if I’m going with LED lighting. Is it 2 lights per shelf but then how many shelves could I reasonably use? I’m thinking only 3 with LEDs and one short for storage at the bottom or a couple shorter at the top? For some reason I can’t picture this in my head or figure out how many lights/shelving units I would need. I have an area in the unfinished yet heated basement so more than enough room for whatever setup.
Hi Christina! First, we should say whether it’s best to get LED or fluorescent grow lights is going to depend on what you’re trying to accomplish. With the metal shelving unit setup we recommend in this article (which are standard shelving units), fluorescents actually work best if you’re trying to grow a lot of seedlings or microgreens (3+ shelves). That’s because they’re lower intensity lights (relative to LEDs) and you can hang them just a couple inches above the top of your seedlings/plants. We use fluorescents for this reason — and because it’s what we’ve been using for about 10 years.
However, if you’re just growing a few seedling flats (say one or two shelves worth), then LEDs grow lights may be best. As we mention at the bottom of the article, the general guidance is to hang LED grow lights about 24-28″ above the tops of your seedlings, but you can put them a bit closer. Yes, as you mention that would mean fewer shelves in your LARGE setup. And due to the higher intensity of LED lights, you could just do one LED lighting system per shelf, rather than 2 per shelf required with the fluorescent shop light setup. With LEDs, the very top shelf would be storage and to hang the top row of LEDs. Below that would be the two shelves with plants/seedlings on them. You might be able to squeeze three rows in to this setup with LEDs hanging closer over top of the plants.
A third option (which we’ve also done with fluorescents) is to keep the lights (LEDs or fluorescents) running around the clock and swap out seed trays on 12 hour shifts. This gives your plants the needed day/night rest cycle and maximizes the amount of seedlings you can grow under your grow light system.
Does this info help you figure you what you need and answer your question?
Thank you for making this so easy to replicate. I’m about to build a large grow system. I love the idea of (at least near) continuous micro greens. Is a large set up like very conducive very many other types of crops? Say more mature greens or berries or something? What do you guys like?
This system is ideal for plants that grow to no more than ~8″ in height before harvesting or transplanting, so cane berries wouldn’t be ideal. You could probably grow strawberries under this grow light setup, but we’ve never experimented with that since we grow them outdoors. We also like to grow Austrian winter pea shoots under our grow lights, which provides a continual harvest of cut-and-come again greens throughout the year – including in the summer when it’s too hot here to grow them outdoors. More on that here if you’re interested: https://www.tyrantfarms.com/how-to-grow-an-endless-supply-of-pea-greens-indoors/.
Also if I may ask, do you have any reasoning for using both warm and cool spectrum bulbs for what would otherwise be vegetative stage grow projects (greens)? I thought cool spectrum is all this type needs. Thank you.
Our understanding is that plants in all stages of growth really benefit from a full light spectrum comparable to what they’d get outdoors via natural sunlight. Since it isn’t too hard to mix cool and warm spectrum fluorescent bulbs in this grow light setup, we figure it makes sense to go ahead and do so. You could probably get away with a more narrow spectrum bulb setup in a pinch.
Hi, thanks for all your great info. I’d like to try making something like the large system but money being tight I’d like to keep costs down as much as possible. I was thinking I could use wood & hardware I already have to build the system directly on the wall. That way I’d only have to purchase chain, lights, and a timer. Do you forsee any problems with this method? Would my drywall be in danger from moisture? Another question I have is about sprouting the seeds without using multiple warming pads. Would it be possible to sprout more seeds at once in wet paper towels on 1 heat pad and then transfer the sprouted seeds to the starter mix? I’ve never successfully started seed indoors and I’m the scatter-and-cross-my-fingers type of gardener so any advice you can provide is very helpful!
Hi Allison! Answers to both your questions:
1) The devil’s in the details as far as whether you’d potentially cause water damage to your drywall. It really depends on how close your seed trays are going to be to the wall, and how careful you are when you water your plants. But, it shouldn’t be a problem so long as you’re careful. Frankly, the potential problem you’ll probably need to be more concerned with is the wood underneath your seed trays and the flooring underneath your seed starting station. You’ll inevitably have some water or soil spills, so ideally you can have your setup over tile or vinyl for easy cleanup.
2) Yes, you could easily start multiple seeds on a warm, damp paper towel, then transfer them into cells with seed starting mix once they germinate. Certain plant species really don’t like root disturbance (example: cucurbit family plants like squash and melons) so just be careful not to damage the delicate roots when you transplant them. When we’re starting a ton of heat-loving summer seeds, we often use small Ladbrooke soil blockers for the reasons you outlined, then pot them up to larger blocks 7-14 days after germination, but that’s probably not something you need to worry about given the extra cost and expertise involved: https://www.growjourney.com/use-ladbrooke-soil-blockers-seed-starting/. Something you may want to consider later down the road though. 🙂
Best of luck with your new DIY grow light setup!
Great guide! I’m planning to start with the smaller grow light setup. Thanks for sharing!
Hi Aaron,
Quick question, as I am trying to set up an indoor grow area to start my seeds early. I was wanting to purchase LEDs for each row and then I read below that when using LEDs over newly germinated seedlings that they are to be hung around 2 ft above them? Is this correct? If so, does this shelving unit not work with LEDs since each shelf is most likely no more that 1.5” tall? Or, once germinated, is it possible to hang an LED simply at the top of the bottom of each shelf to give about a foot of distance between the light and the plants? Please let me know if this unit with the 5 shelves will work if I purchase 5 double LED lights for each shelf. Thanks!
Sorry when I used “, I meant ‘, meaning 2 or 1.5 feet not inches. Thanks!
Hi Maegan! Very sorry for the confusion on that and thanks for catching the mistake. Yes, LED lights are going to be hung ~ 24” above the plants/seedlings, thus you can’t set up all six shelves in the larger setup. You’d only use four shelves, three of which have plants on them. Therefore you only need 3 LED lights. We’ve edited that section of the article. Thanks!
Hi! Thanks for all of this info!
I have 24 inch LED lights and some of my seedlings are a little leggy so I put the light closer. Still some seedlings are leaning towards the light. Should I have two LED lights for each shelf? Trying to figure out if I need to buy more. The 24 inch LED lights you have the link for are what I have. The box said the lights can go between 8 inches and 18 inches, so I have them about 10 inches right now.
Any thoughts on this?
Hi Shaina! So sorry we missed your comment/question about your LEDs. If your seedlings are still leggy, you can either shift the lights over the seedlings each day at set times to a slightly different spot so as to be directly above the seedlings OR get additional lights. It’s hard to say for certain what’s happening without seeing a photo of your setup. Feel free to email a photo to me at aaron @ growjourney dot com (spelling out to protect from bots) if I can be of help.
Thanks! We’ve followed this setup and are starting a course for patients at the in-patient hospital I work for.
When first starting seedlings and using the humidity dome… If some of the varieties come up, but others are lagging behind should I remove the tray from the heat mat and remove the humidity dome? I don’t want to kill off the seedlings that have come up, but at the same time I want the remaining seedlings that have not emerged to have the best chance of making it.
Hi Justin! Frankly, we’re not fans of humidity domes for two reasons:
1) They tend to make it too humid and not allow for adequate airflow. These conditions promote a fungal disease called “damping off” which infects the stems of the young seedlings, killing them and then spreading to other plants in the tray.
2) The domes make it hard to get the grow lights close enough to the seedlings to provide adequate light and they also filter some of the light out when moisture collects on the top surface of the dome.
Instead, we recommend going dome-free and just doing a good job of watering your pre-emergent or already emerged seedlings while providing them ample light and airflow. This approach only requires 1 or maximum 2 waterings per day depending on the stage of seedling development. Prior to germination or when the seedlings are young, one watering will suffice. Once the seedlings are fairly large and near transplanting stage (6-8 weeks old), 2+ daily waterings may be needed depending on the size of the seed cell and plant that’s growing.
To directly answer your question: if different plant species (example: peppers and tomatoes) or varieties of seedlings within the same plant species (example: different cultivars of tomatoes) don’t emerge at the same time, that’s perfectly normal. Days to germination varies by species and sometimes even a little bit by cultivar. Please let me know if this reply provides clarity for you and/or whether you have additional questions. Good luck!
Thank you. Very helpful!
Up to this point we have been removing the dome as soon as a little more than half of the tray has sprouted. Would leaving the emerged seedlings on the heat mat while the remaining seeds germinate and sprout be harmful to them?
Also, how close is too close as far as the LED lights go? Various sites state that there is no hard and fast rule regarding this – most are saying 12-20 inches (or follow the guidelines that came with whatever lights you purchased). I know that if they’re not close enough the plants will become leggy, but too close they may start to bleach or burn. Our current setup allows for 12 inches but not much more.
No, leaving the emerged seedlings on the heat mat while the remaining seeds germinate and sprout would not be harmful to them. Unfortunately, there isn’t a definitive answer on the LEDs because it depends on your specific equipment, but the 12-20 inch range is standard. It won’t take long (~2 days) for you to notice either extreme: leggy seedlings or sunburned seedlings.
Hi Aaron,
I noticed that the first two links to your recommended four-foot LED lights go to pink/purple lights and the third link goes to warm white lights.
Is there really a difference in the effect this has on the plants? For aesthetics, I’d prefer the warm white lights over the purple ones (my rave days are long past) but my friends swear by their purple lights for seed starting.
Which kind do you use?
Thanks!
Hi Robin! Short answer: you’re fine to get either option (pink, purple, or white LEDs) for seed starting.
Longer answer: there are some differences between setups. Pink LEDs are a combination of white and red LEDs. Purple LEDs are a combination of blue + red LEDs. White LEDs are only white. The reason for these differences isn’t merely cosmetic. For instance, purple LEDs contain the red spectrum for maximum photosynthetic efficiency, but this can make plants grow too fast, which is why it’s balanced out with blue LEDs so plants stay healthy and more compact/robust.
From an energy efficiency standpoint, purple LEDs are the most efficient, but the difference in energy/money savings won’t be significant for a small home setup (more so if you have a giant greenhouse operation where minor differences become magnified with scale). Pink LEDs are the second most energy efficient setup, followed by white. “White” LEDs also vary by manufacturer and system: cool, warm, mint, etc. Again, for the sake of seed starting at home, the differences between the color of LEDs will be minimal, both on plant health and energy efficiency due to the quantity used and the fact that you’re typically only growing seedlings under lights for 6-8 weeks prior to transplanting.
So if cosmetics and not reliving your rave days is the most important factor to you, you can dance to whichever color floats your fancy. 😉