Using a Grow Light to Start Seeds Indoors

Updated on March 20, 2020
KCO profile image

Katy's garden of herbs, peppers and greens is constantly expanding as she learns new techniques and tries new plants!

Thinking about growing some herbs or veggies? Starting them from seed is a great choice but it's super hard without an LED or at least some form grow light.

The natural light from a window is not going to cut it! Seedlings don't do well when in a window. Even the most hardy seedlings have to struggle. That's not what you want for starting out a garden.

Thankfully, adding a grow light is super easy. Read on to learn how to start your seeds out right under grow lights!

Do I Need a Grow Light for Germination?

Before you buy a light, you'll want to know if it's really necessary.

Let me tell you what all experienced gardeners know: seedlings are so hard to start indoors with natural light. Even with a sunny window, they only get partial light and you can't control it.

Even if you got your seeds to sprout and they seem healthy, they probably didn't grow to maturity. This is because they spend all their energy growing towards the sun instead of developing. They burn themselves out before they can get started!

Using a grow light to start your plants inside takes so much guess work out of growing. Whether these sprouts will end up in the garden or stay inside forever, using a light will make all the difference.

Grow Light 101
Grow Light 101

LED Grow Lights for Seedlings

LEDs are a great option for grow lights. They are a bit more energy efficient than fluorescent and there's a lot of options out there. You'll find two main types: free-standing and a traditional hanging light.

Free Standing Lamp ($30-$40)

For a small area free-standing lamps are a good option. For my earlier years germinating seeds inside I got this Winjoy 30W Lamp. I'd recommend it for around 10-15 seedlings.

It keeps things on a small scale and affordable. You'll find this lamp is really handy because you can adjust the height of the lights as your seedlings grow.

Hanging LED Grow Light ($50-$100+)

If you want more than 20 seedlings, you'll need a classic grow light that hangs from the ceiling or a shelf. This Goldspark 600W light is very affordable and my plants have thrived under it. I use it indoors for peppers and tomatoes.

I didn't know until I got it that it has a switch that allows you to set the spectrum. So I could use just the blue light while the plants were young. Then I flip the switch to the Bloom setting once they're more mature to use the red spectrum.

No need to buy another light or swap them out!

How to Pick an LED Grow Light

The market is now flooded with LED lights. That's great for us as growers but how do we choose?

Here are some important considerations when selecting an LED light:

  • Must have Red and Blue spectrum.
  • Anything over 100W needs a cooling system.
  • Option to select Flower or Veg spectrum is helpful for seedlings.

Seedlings that you start indoors under grow lamps are more hearty when they reach maturity
Seedlings that you start indoors under grow lamps are more hearty when they reach maturity | Source

Red vs Blue LED Spectrum for Seedlings

The spectrum that your grow lights emit is very important and it can get pretty technical. I'll give you the overview you'll need for growing seedlings and you can follow these links if you want to learn more.

You'll see that many LED grow lights emit in the red and blue spectrum. This is because plants evolved to use red and blue wavelengths most efficiently. You can actually control whether a plant uses its energy for growth or flowering by controlling the spectrum.

Blue Light for Veg/Growth

A plant exposed to blue light only will spend that energy on growing and building it's roots. This is called the Veg stage.

Veg is most important early in a plant's life. Blue light is thought to be good for seedlings. But if you keep an indoor plant under a blue LED for all of it's life it won't grow to its full potential. Learn more about what blue spectrum does to plants.

Red Light for Flowering

A plant that receives red light only will start to flower. Obviously, this is the Flowering stage.

When you want a plant to give fruit, this is the wavelength you should expose it to. For most vegetables and herbs you don't want much red light early in it's life cycle, if at all. When you're growing herbs indoors to use for cooking you don't want those to flower, so avoid a lot of red light.

Full Spectrum for Indoors Plants

Instead of just red or blue light, you will see some LEDs advertising "full spectrum". These lights will hit more of the visible light spectrum than just red and blue.

You'll want to consider an LED or fluorescent with a wider spectrum if your plants are staying inside. The fuller coverage of light will produce higher yields.

Other Considerations for Growing Sprouts

Light isn't the only ingredient to strong seedlings. You will also need to pay attention to the seed's water, temperature, humidity and nutrients.

Seedlings can benefit from some added nutrients but be sure to read on how to use fertilizer on seedlings before you start.

When Should I Add a Light to My Germinated Seeds?

Add a light as soon as any green part of the plant emerges. The new leaves need as much "sun" as they can get to give the plant energy. That means starting as soon as possible.

I turn my lights on as soon as I sow the seeds. The light doesn't matter before they've sprouted but it doesn't hurt at that point.

Also, the light gives off some heat which is always helpful for the little guys!

How Long Should the Grow Light be On?

How long do new seedlings need light? For the first three to four weeks, leave the light on for at least 18 hours.

After the first month you can decrease light exposure to 10-14 hours a day. Plants that need a lot of direct sun like peppers and tomatoes should be on the higher end of that spectrum. Plants that prefer a little less light can get by with closer to 10 hours or even 8 hours.

Light Timer

If you bought an LED light with a timing feature it's easy to set to ensure your new plants get the right amount of light every day.

If your light doesn't have a timer, you can buy an outlet timer that will turn power on and off on a schedule.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Katy Medium


Submit a Comment

No comments yet.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)