Outredgeous Lettuce: How To Easily Grow A Crazy Bright Red Lettuce Indoors

Yes, Outredgeous Lettuce and Not Outrageous Lettuce

Do you like the play on words with the naming of Outredgeous lettuce? 

Look at that lettuce; if that isn’t an outrageous red, then I’m not sure what is.

Outredgeous lettuce, when mature, is a loosehead type of romaine lettuce. Later in this article, there’s a picture of one near mature from our garden. But Outredgeous lettuce also makes a beautiful baby leaf green for salads and toppings for tacos, nachos, etc.

The story behind Outredgeous lettuce is fascinating; we’ll discuss that later in the article. We also discuss the nutritional value of red-leaf lettuce.

First, we want to explain how we get such a deep red color on our red-leaf lettuce.

Tray of Outredgeous lettuce

Outredgeous Lettuce 23 days after planting starts to turn dark red. Red leaf lettuce starts green and gradually turns redder as it grows under the correct light conditions.

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How to Turn Red Leaf Lettuce Redder

If you’ve read any of my microgreens articles, I often state that the type of LED light you use doesn’t matter as long as the color temperature is over 5,000K. Here’s a link to the lights I use for most microgreens.

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FREE Home Microgreens Grow course that teaches you the basics of growing microgreens in your home! There are 12 video lessons (over 120 minutes), downloads, and more written information and tips!

However, to turn lettuces like Outredgeous lettuce and Ruby Red Leaf Lettuce red requires more power than LED shop lights can produce. 

The tray of Outredgeous lettuce shown in this article is grown under a Mars Hydro SP150 LED light. We grow up to four trays under the SP150, though, as you will see, the light coverage is a bit small for a 2- by 4-foot area without a grow tent. 

The TSL 2000 or the SP3000 would be better for my growing area. Currently, we are working with vendors for trial lights to do reviews.

The SP150 does a good enough job at a reasonable price to grow red lead lettuce. Later in the article, there will be more information about lights and how to set them up.

Listen to an Audio Version of the Article

We don’t just read the article word for word in the audio version; it’s a stand on its own piece of content that includes more details on the topic. These can include more tips, opinions, details, data, and information on this and related topics. 

The Microgreens Podcast Episode 8

Pin and Share This Image to Your Microgreen Pinterest Board!

pin for outredgeous lettuce

How to Grow Outredgeous Lettuce

We grow lettuce a bit differently than microgreens.

The reason for this is that we are growing baby leaf lettuce larger than microgreens. Therefore, each plant will take up more room in the tray. So dumping a boatload of seed on the soil isn’t going to work out too well.

The leaves in the middle of the tray will brown out due to the lack of light. 

The second reason is that lettuce seeds need access to some light to germinate. Therefore, we use a clear dome to allow light to reach the seeds and retain humidity around the seeds sitting on the soil surface.

The Steps to Planting Lettuce Indoors

Below is a video of how I plant lettuce and grow it indoors. The lettuce grown in the video is Ruby Red leaf lettuce, but the same process and amount of seed sown is the same for Outredgeous lettuce.

Photos and text below the video specifically discuss growing Outredgeous lettuce.

My View From The Woods is my YouTube channel if you want to subscribe.

As I mentioned, the same planting process is followed with Outredgeous lettuce. Let’s take a look at the growth stages of Outredgeous lettuce.

Outredgeous Lettuce Seeds

Lettuce seeds, for the most part, look similar; below is a photo of 0.8 grams of lettuce seeds.

In the tray is 0.8 grams of lettuce seeds.

We sell Outredgeous lettuce seeds in the Home Microgreens Store. These are certified organic seeds, and we use them for growing indoors and in the garden.

deep red color on outredgeous lettuce

Besides microgreen seeds, the Home Microgreens Store also sells lettuce seeds to grow inside to baby leaf size or grow them up and transplant them in the garden.

You may think 0.8 grams of seed isn’t enough for a 1020 tray. But we believe 0.6 grams of seed would be better because these plants will grow into baby-leaf-sized plants, and crowding is an issue.

spacing of lettuce seeds

As you can see in the photo, the seeds are spread quite thinly. Try your best to evenly space the seeds for the best results. You can click the image to expand the view.

What to Do Before Planting Lettuce Seeds

Good soil makes all the difference. We recommend our own soil blend or Fox Farms Coco Loco.

Wet the upper 1/3 of the soil profile. There’s no need to wet all of the soil in the tray. We use a spray bottle, exactly like in the video. We also mist the seed after sowing it.

After the plants grow and the humidity dome is removed, we start bottom-watering the lettuce tray. 

The heavy-duty trays we use come from Bootstrap Farmer. We love these trays for their strength and durability. Check them out here.

Light Placement for Starting Lettuce Seeds

When we start lettuce seeds, we place the light slightly higher than later when the plants begin to grow as you can see in the second photo. It’s about 2 feet above the top of the dome. 

Lettuce seeds need light, but not intense light at this stage.

outredgeous lettuce under dome
light setting above outredgeous lettuce

This is the advantage of the SP150. The ratchets make adjusting the light height much more manageable. We grow our lettuce on a 2- by 4-foot shelf holding four trays.

This way, we can have lettuce growing in all stages for a constant supply even during the darkest and coldest central New York days. 

Germination and Seeding Care for Outredgeous Lettuce

Lettuce germinates at varying rates depending on light, temperature, moisture, and variety. 

Our Outredgeous lettuce started germinating in less than 2-days. We didn’t record temperatures, but it was cooler outside, though the house may have been in the low 70s.

outredgeous lettuce 2-day germination
outredgeous lettuce 2 days close up

Notice the moisture in the dome. Usually, the moisture condenses and falls back onto the soil. But in some cases, such as when the shelf isn’t level, soil moisture levels can fluctuate. 

If part of your lettuce tray looks dry, use a spray bottle, and mist the soil. Usually, you can tell dry areas as the soil is a lighter brown in color. 

Keep the dome on the tray and the light elevated 18- to 24 inches above the tray if possible.

We run our lights 15 to 16 hours per day.

After 4-days

After four or five days, the lettuce forms a stem, and the leaves get much bigger.

outredgeous lettuce seedlings

We decided to keep the dome back on and carefully mist the lettuce seedlings. The lighter the mist, the better, but don’t worry if the plants tip over. They will straighten back up unless you blast them out of the soil.

We Use These Microgreen Trays

We use Bootstrap Farmer Shallow Heavy-duty trays to plant 1010 or 1020 trays. We also use their deeper trays to plant peas or other uses.

These trays will never be damaged with normal use.

Heavy-duty Trays

When we grow microgreens for ourselves, we use the Home Microgreens Trays & Soil. We like the amount of microgreens these trays grow, and we find we can either stagger plantings or double up trays to fit our microgreen needs.

Home Microgreens Trays

Start Bottom Watering

We water the tray from the bottom when the lettuce seedlings are at this height. Simply remove the planting tray or lift one end and pour about 2 cups of water into the bottom tray. 

When you lower the planting tray, the water is absorbed into the coconut coir soil base.

We check moisture levels daily. At this point, you may need water every other day or so. But once the plants get larger, you’ll need to water them almost daily.

One Week After Planting

The dome can come off the Outredgeous lettuce tray a week after planting. Don’t take that too literally; sometime between six and eight days is sufficient.

one week after planting lettuce seeds
close up of week old outredgeous lettuce seedlings

At this point, you can see how well you spread the seeds. Our tray has a few light areas and some denser ones. It’s ok; they will grow to fill or push the outside plants outward. But again, the more evenly spaced you can sow the seed, the better.

In the close-up, you can still see the seed husk attached to the cotyledons.  The red color will not show until the first true leaves form.

The fuzzy white hairs on the plants at the soil surface are root hairs and not fungus. You can click the image and expand it for better viewing.

Now we lower the light to about 12 inches above the top of the lettuce seedlings.

What A Difference A Day Makes

The lettuce in the previous photos is seven days old. The picture below is from the following day. 

color forming on outredgeous lettuce
true leaves on outredgeous lettuce

The first true leaves start to grow, and you can see they are tinged reddish-brown. They will stay more or less this color for the next week to 10 days before the deep red color starts to show.

Outredgeous Lettuce on Day 15

As the lettuce grows, check daily or every other day if the tray needs water, and keep the light about 12 inches above the lettuce.

Sometimes, we raise the light higher for better coverage when four trays are on the shelf. The lettuce grows well, but the color will be less bright.

Don’t put any light that puts off some heat too close to the lettuce, as the leaves may burn or curl up on the edges.

Here is our Outredgeous lettuce 15 days after planting.

growing lettuce inside outredgeous lettuce
close up of outredgeous lettuce after 15 days

The lettuce has filled the spaces, and the leaf size is larger. 

If you wanted, this lettuce could be harvested. However, we usually wait another week as the lettuce will start to color up even more.

Color Improvement Day 23 – Ready to Harvest

See the color improvement after eight more days? 

outredgeous lettuce ready to harvest
deep red color on outredgeous lettuce

Also, notice the more intensely colored red leaves on the left side of the tray.

This is because that side is more directly under the light. Light intensity is key to increasing the red color of the leaves.

This is also why the lettuce is greener inside when you move the outside leaves away. 

The lettuce is ready to harvest. 

Use a sharp knife or scissors to harvest the amount you want for your salads. Cut what you want and leave the rest to continue growing.

Can You Get More Than One Cutting of Lettuce?


Cut the lettuce about 3/4 inches above the soil surface, and the lettuce will regrow. See the photo below.

cut lettuce tray regrown

The right side of this tray has been harvested and has started to re-grow.

It’s possible to get three cuttings from one tray. However, it gets harder to water the tray as it becomes more root bound, and the lettuce will get slightly more bitter.

That’s How Simple It Is!

Follow the directions in the video and this post; the lettuce will be ready in as little as 23 days! 

We also published another article on growing Ruby Red Leaf Lettuce. Click this link to read that article.

Both Outredgeous and Ruby Red lettuce seeds can be purchased in the Home Microgreens Store. Enter “lettuce” into the search bar, and both appear.

Home Microgreens Store

All the supplies and microgreen seeds you need to grow beautiful and nutritious microgreens at home!

Our prices are as competitive as the larger seed sellers. We also have our own soil, microgreen kits, and trays!

Some Interesting Outredgeous Lettuce Facts

Outredgeous lettuce is the first vegetable to be grown and eaten in space! It grew on the International Space Station in 2015! You can read more about it in these two articles:

Veggie Plant Growth System Activated on International Space Station
Meals Ready to Eat: Expedition 44 Crew Members Sample Leafy Greens Grown on Space Station

Why Eating Fresh Cut Lettuce is Important

The white milky sap that comes out of fresh-cut lettuce is where most of the lettuce nutrients exist.

The white fluid is called Lactucarium or “milky extract.” The edible lettuce’s genus and species are Lactuca sativa, named after the milky extract that flows from fresh-cut lettuce. 

Usually, within 24 hours of harvest, the sap has deteriorated, as have the nutrients within it. 

This is why freshly cut lettuce tastes better and is better for you!

For more information on the nutritional value of red-leaf lettuce, read this article


  • Todd

    Todd is the founder of Home Microgreens & the Home Microgreens store. He also writes for several other websites, including MyViewFromTheWoods.com. Todd worked at a large farm market, garden & nursery center for 20 years. Somehow he snuck off to become a geologist and professor before coming back to his senses to write & lecture about microgreens and gardening. When not at the computer, he can be found in the garden, trout stream, or mountain trail with his new Springer Spaniel Caden.

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