Alberta's Best Garden Blog

Grow Lights 101

Grow Lights 101
By Rob Sproule

What’s on the Menu

Our tomato plants are frozen solid 🙁 but that doesn’t mean the end of home grown veggies! Let’s talk about how to ripen tomatoes when it’s -40 C outside….

“Growing your own food is like printing your own money.”
– Ron Finley

It’s pretty fatalistic seeing your tomato plant freeze solid. Every Fall we wave goodbye to home-grown goodness and say hello to store bought everything. But it doesn’t have to be goodbye…

Growing food indoors is exploding in popularity. It’s a natural extension to the grow-your-own movement which has transformed gardening. As we reach for the winter comfort food and cut into our pale, bland imported tomatoes, we’ll start craving that home-grown taste and vitamins. But with our grim levels of winter sunlight, naturally grown veggies are bound to get pale and stringy. That’s where technology steps in.

At our lowest, we get a scant 10 hours of natural per day (that’s if it’s not cloudy). Most edible plants needs 14-16 hours of light per day for health and yield. If it’s not getting enough light, it will reward you with small leaves, spindly thin stems, and a pale, sickly appearance.


The bulb defines how effective your grow light is. It’s all about the width of the spectrum, as plants respond to blue, cool light different to hot red light. Here’s the basics:

  • Incandescent: Cheap, old school, and very hot. They’re functional for basic leafy veggies and herbs, especially in partnership with natural light. But keep plants 18” (at least) from the bulb so you don’t burn them to a crisp.
  • Fluorescent: Popular with home-growers, these bulbs emit a broader spectrum than incandescent, and they’ll far cooler/ safer. But they still don’t have spectral range for flowering and fruiting, so stick to leafy greens and herbs for this one.
  • LED: The new kid on the block, LEDs are redefining home growing. They’re cool, last for a crazy long time, and emit a full enough spectrum to allow for leaf growth, flowering and fruiting. Costlier than the others, it’s worth it for how long they last and being able to grow cherry tomatoes in January.

Learn more about growing food indoors, with Alberta’s Best Gardening Blog

If you invest in some LED grow lights, you’re going to want more than lettuce. Here’s the options:

  • Tomatoes: You read that right. Start from seedlings and transplant. They’ll need LED lighting to set fruit. Stick to cherry tomatoes; beefsteaks are a bridge too far indoors. If you’ve spoiled yourself on home-growns, you’ll crave the taste.
  • Beans: Bush beans (the non-climbing kind), are possible but not popular. You’ll get a few beans per bush and won’t get the “Wow” difference in the taste between them and store bought.
  • Spinach: You technically don’t need a grow light for this, but using one will reward you with richer, darker, healthier leaves. Ironically it often grows better indoors in winter because there’s no heat to make it bolt. Harvest the outside leaves first and work your way inwards.
  • Lettuce and Salad Greens: The staple of growing food indoors, salad greens are easy, cheap, and will keep your plate topped up with vitamins throughout the winter month. You can grow them without a grow light, but they will lack the taste and nutrition that supplemental light brings.
  • Herbs: I’m going to batch these all together, even though some herbs (like primadonna Basil), require different watering. Grow from seed and harvest the new growth often (the best tasting), to make it fuller. Home grown tastes so much better, and is so much cheaper, than store bought.

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