Ashley's seedlings growing happily under their grow light!
By Lizzi Brosseau
Getting the Light Right for Indoor Seed Starting
Have you been curious about seed starting? Or maybe you’ve tried growing from seed before, but have struggled to get the right amount of light for your seedlings. This has been a problem for our very own Ashley Swansong, so this year she bought a grow light to help ensure that her seeds have all the light they need.
To be sure she is using the lights correctly, Ashley reached out to Kody Bruner, from Moonlight Garden Supply Co., to get tips for setting up her grow light, and shares what she learned in the video below!
What is a Grow Light?
There are two main types of grow lights: fluorescent and LED. To be effective growing plants, these lights need to mimic the color temperature of the sun, which is about 6500 Kelvin (noted as “6500K” on light bulb packaging). When you are looking for light bulbs to use as grow lights, look for this number on the box!
Ashley has a T5 fluorescent Agroflex, 120v 244 tube light, with a regular plug that goes into the wall. This light is very commonly used for growing plants because it has good coverage and spectrum for vegetative growth, which is important for seed starting.
How to position your grow light, and when and how long the light should be left on are the most important considerations of using a grow light effectively. You want to be sure you have these dialed in, so that the seedlings aren’t stretching for the light and develop weak stems that can’t support the plant.
Positioning your grow light:
Fluorescent light: 6-8 inches between the light and the soil of your starts.
LED light: 12-30 inches away from the soil, since they are a bit stronger.
If your plants aren’t fully covered by the light, then make sure you are rotating your plants periodically, so they get even coverage.
When to turn on the light:
Wait until the seedlings pop out of the soil to start using the light. This will help avoid “leggy” seedlings, which could mean they aren’t strong enough hold themselves up.
How long should the light should be left on:
About 16 hours is good in the vegetative state, and 12 hours once the plant starts to flower.
Sky hooks hold up grow lights and allow them to be easily adjusted.
Tips and Reminders for Using Grow Lights
Skyhook rope will help make it easier to lift and lower lights. Ashley found this to be very helpful!
Buying a timer is a great way to ensure that your seedlings are getting optimal and consistent amounts of light without having to schedule your day around them. (We almost want to suggest that this is an essential part of using a grow light. It’s very easy to forget to turn on or turn off a grow light, trust us!)
If you can’t buy a grow light, try using fluorescent lights that are in the 6500k spectrum in your home, or position your seedlings in a south facing window.
Getting the Best Start on your Starts!
We hope these tips help you grow happier and healthier seedlings for your garden, and that you feel confident using your own grow light.
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Modern Gardener Host and Author
Lizzi works for PBS Utah as a digital producer and host of Modern Gardener. Read more