Grow Lights for Seed Starting
The market is flooded with grow lights, and the price ranges are vast - from $20 - $1200 for one light! So what grow light should you purchase to start seeds indoors?
Grow Lights - Demystified. A bit.
I went down a RABBIT HOLE on this one my friends. A big thank you to Tynan over at Anything Grows for shedding some ‘light’ on the topic lol.
Here is the lowdown:
Grow lights can be incredibly expensive, and the options available are staggering. The legalization of the cannabis industry means that some home growers need lights that are more powerful and precise. If you are starting seeds for your personal garden, and you don’t start them too early (this is key), some basic lighting is going to do the trick.
Light types: CFL, LED (and HPS?)
You will likely be choosing between compact fluorescent (CFL) and LED. CFL is less expensive to purchase, but it uses more energy and puts out more heat. LED is more expensive to purchase, but it uses less energy and produces less heat. Another type is HPS (high-pressure sodium), but the amount of heat they give off often requires specialized venting & cooling equipment - so I’ve eliminated them from our discussion of simple grow light setups for home gardeners.
Light Temperature, PAR and PPFD
Light temperature tells us about the colour of light. It’s measured in Kalvins on a scale of 1000 (warm red) to 10,000 (cool blue). Most of the lower-end grow lights will be around 3000k (warmer, redder) or around 6400k (cooler, bluer), and many of them will be full-spectrum (so they will add yellow and green light so the light looks more natural to the human eye). More red light supports the reproductive stage of growth - flowering and fruiting. More blue light supports the vegetative stage of growth (which creates strong roots and leaves). New light science tells us it’s far more complicated than just blue and red light, so Kalvin is not in a complete measurement. The general wisdom is that a home gardener should be using a light that is around 6400k, as your plants will reach the fruiting and flowers stage once they are outside, and have a WAY more efficient grow light (the sun).
When we get into higher-end grow lights, you will start to see a discussion about PAR; which is the type of light wavelengths a plant can actually use, and photosynthetic photon flux density (PPFD); which is a measurement of how much of the usable light is actually making it to the plant. These measurements really tell us the intensity of the light. So even if you get the right colour (Kalvin) if your light isn’t intense enough, your plants will suffer. If you plan on purchasing higher-end LED lights or need your plants to fruit or flower inside, you need to dig into this topic more. If you want to grow a few veggies you can pop outside, you can keep things more simple.
Grow Light Options for the Home Gardener
Here are four set up options for you, listed in order of price from lowest to highest.
A Sunny Window + Fluorescent bulb
A basic grow bulb near a sunny window.
A sunny window is going to get you farther than you might expect. Newer windows do have coatings to block out light wavelengths that aren’t great for humans, but necessary for plants. You can ‘boost’ a sunny window with something simple like a desk lamp with a Sunblaster Bulb - (I use the 26 Watt) available at most gardening centres. Do keep in mind - windows can get cold (like when it’s -28 out), and really hot (like the 15 times I cooked my seedlings).
Investment: About $25 for the bulb & lamp
Coverage: About a 2x2’ space (in a sunny window)
CFL “Shop Lights”
You can purchase shop lights (just have a look at any hardware store) that will fit a T8 or T5 bulb (these are just different sizes). Shop lights can often be found at second-hand renovation stores. Lots of home growers just use a cool light fluorescent bulb. You could upgrade this a bit by finding a 6400k grow light bulb.
Investment: About $60 for two 48” fixtures - less if you find it used.
Coverage: About a 2x4’ space
Grow Lights - Fluorescent
I have both LED and CFL lights on my seed starting shelf.
Taking it up a notch, you can invest in fluorescent lights designed specifically for growing. I’m not a fan of the ‘blurple’ (red and blue) grow lights. Newer science tells us plants do need more than just blue and red light, plus I hate how they look. A purpose-built grow light will have more intensity and a wider spectrum of light. The most common one I’ve seen on the market is the Sunblaster T5HO (high output) ‘combination’ light (it includes a reflector). A 48” goes for around $60-$70. So you’re looking at a $120 investment per 2’ x 4’ shelf.
Investment: About $120 for two 48” fixtures.
Coverage: About a 2x4’ space
Grow Lights - LED
The top end of your grow light options is an LED. There are lower-end LED lights (these have less light intensity) that go for about $100/48” fixture, and the higher-end lights can range from $350 - $1000+ for coverage of a 2’x4’ space. Keep in mind, some of the folks purchasing these more expensive lights have revenue-generating plants (like cannabis, greenhouse growers, or flower farmers) so that higher-end price makes sense for them. Unless you’ve come into some surprise money, you do not need a high-end LED light to grow veggies & flowers for your backyard. I purchased the Monios T5 LED, I had to get 4 to cover my 2’x4’ space, so the investment was just under $200. These lights are 3000k, so we’ll see if my plants suffer because they don’t have that blue light to support root growth. In 2022 I purchased the Sunblaster LED grow light - it’s about $120 for 48” - so about a $240 investment for a 2’x4’ space. This light is 6400k, so I should be able to do some experiments to see how the two compare.
Investment: About $200 - 250 for two 48” fixtures (lower end) or $300 - $1000 for 2x4’ coverage for higher end lights.
Coverage: About a 2x4’ space
Important Note about light quantity: I’ve outlined the minimum lights you’ll want to have in each space. If you have a larger budget, you can certainly choose to have more lights - ie 3-4 fixtures per 2’x4’ shelf instead of just two.
Using Your Grow Lights
Once you purchase your grow lights, it’s time to install them and get some plants started! A few quick tips for you:
Not all grow lights come with installation hardware. You may need to head down to your local hardware store to select some installation hardware (like chains and clips) to install lights on your particular shelf.
Your grow lights should be on about 18 hours per day. I suggest investing in an automatic timer
Your lights need to be close to your seedlings, about 2” to 4”. If your seedlings are long and leggy, they aren’t getting enough light. If the leaves have brown on them - they may be getting burnt (if they are too close).
To learn more about what you need to start seeds, don’t miss our post: Seed Starting Set-up
I’m offering a FREE virtual seed starting class on Thursday, February 24th. Sign up here to reserve your spot!