The Best Way To Grow Basil Microgreens – Testing 2 Methods

Basil microgreens are one of the easiest microgreens to grow. I’ve mentioned this before in my articles and podcasts and have never had an issue growing them.

It is true that basil microgreens grow slowly. This is why I grow them when I test different types of potting mixes and grow media because I want to see how long the growing media provides nutrients to the microgreens. They also do not germinate very well in cooler conditions.

But besides how long they take to mature and the need for a warmer germination temperature they require no special care.

It is also good news that all of the basil microgreen varieties grow similarly. The only difference is the time to harvest. However, the time basil microgreens need to grow is more dependent on environmental factors such as temperature, light, soil, and moisture.

These young Red Rubin Basil microgreens shown below grow exactly the same as the green-leafed Genovese Basil microgreens.

red rubin basil microgreens

It Never Dawned On Me

In a recent podcast, I was talking to a microgreen grower and he mentioned growing basil under a humidity dome (12:07 point in the podcast below). I took this to mean they grew basil under a dome. Because of how he talked about other microgreens and removing them from the backout.

Because basil microgreens grew so well for me using the weighted blackout method I didn’t think there was a reason to test another growing method.

Here is a link to the article that discusses how to grow basil microgreens. I will also outline the process below in both the video and text.

home microgreens sells seeds

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!

I was curious now.

How well will basil microgreens grow in the domed blackout method?

If you are unfamiliar with the microgreen germination methods, the link will take you to a page that lists all of the methods with short videos for each one.

Home Microgreens Quest

If you have followed this website even for a little bit of time you know my quest is to find the best way to grow microgreens. This includes the best way to grow each variety, the best soil, the best grow media, the best fertilizers, and the best germination and care methods.

Therefore, I set out to test how well basil would germinate using the domed method.

The video below shows the process and I will add to the discussion after the video.

Video: Growing Basil Microgreens Comparing Alternative Methods

How Did the Methods Compare?

Without a doubt, the weighted blackout method grew basil microgreens better.

The Genovese Basil Microgreen seeds appeared to germinate well under both methods.

But once under the lights, the basil microgreens that germinated under the weighted blackout method obviously did much better.

Why Did the Weighted Blackout Method Grow Basil Microgreens Better?

I originally thought that both methods germinated the seeds equally.

On the eleventh day, I thought the reason for the difference in the trays was that the weighted method produced stronger plants.

But on Day 17 (4:25 mark in the video), it is obvious that not only did the weighted method cause the basil microgreens to be stronger, more sturdy plants, but I think the germination or the amount of surviving microgreens is greater.

comparing how basil microgreens grow
Genovese basil grown by two germination methods. Weighted Blackout Method on the left and Domed Blackout Method on the right.

My Two Reasons for Better Growth

The two reasons I think the weighted blackout method grew better basil microgreens are because of more surviving plants, and microgreens that are stronger and sturdier because of better rooting and anchoring in the potting mix.

Let me discuss my reasoning.

Reason One

I didn’t count the actual number of seeds that germinated. I didn’t see many seeds on either tray that hadn’t grown. To my eyes, albeit that I didn’t look that closely, the germination rate was similar.

basil microgreens germinated by weighted and domed blackout

But even on day 11 it appears that there are more plants in the left tray, the weighted blackout method. So either germination was better or some of the plants in the domed method didn’t survive.

basil microgreens on day 11 of a trial growing test

A possible reason for not surviving could be that the roots were growing near the soil surface and not into the potting mix because they had no need to expend energy and burrow into the potting mix.

The humidity was high under the dome so they could get all of the moisture they needed at the surface.

Seeds Don’t Need Much to Germinate

Regardless of the method used to germinate seeds, or the grow medium you use, seeds only need moisture those first few days. This is why you can germinate seeds on paper towels and they look good for the first couple of days.

The seed contains all of the nutrients they need for the first few days of life. Just add moisture.

Left to Whither

Because they had all the moisture they needed, had no use for nutrients, and the dome provided all kinds of space to grow they were happy not to use more energy and root.

When the dome came off and those tender radicles and root hairs met the realities of life out in the open some of them didn’t make it.

This could be the reason the tray of basil microgreens grown under the domed method looks a little light on plants.

Reason Two

The weighted blackout method produces stronger plants and even pushes the seeds into the potting mix for better seed-to-soil contact and better germination.

For all varieties.

Now I do recommend growing some plants using the domed method. The reason for this is that we can’t always be there at the right time to remove the weight when using the weighted blackout method.

We do have lives (well, I don’t; but you do) and it is easy to miss the correct time and it ends up hurting the more fragile microgreens like Amaranth.

But a tray of Amaranth grown under the weighted blackout method and not left too long in that condition will be a better tray than those under a dome.

The Reason For This Is…

The weight on top of the plants forces the roots to grow downward to gain leverage and push the cover and weight off themselves.

Microgreens produce better rooting structures while in the weighted blackout method.

The better rooting structure benefits the plants not only because they were forced to anchor themselves and produce a stronger stem for removing the obstruction, but now they are set to gain nutrients from the potting mix (assuming it has bioavailable nutrients).

While the plants under the dome are rushing to anchor themselves and not to dry up once the humidity dome is removed the plants released from the weight have done this already putting them ahead of schedule.

See the Difference on Day 21?

The basil microgreens grown under the dome are on the left and the weighted blackout method is on the right.

growing basil microgreens

Even though the basil microgreens on the left from the domed method are trying to catch up, they are several days behind those grown by the weighted blackout method.

The weighted blackout method is by far a much better way to germinate basil microgreens.

Hey, But Wait – He said Humidity Dome

You are right, I did make an assumption that when he said humidity dome in the podcast he meant a black or dark dome.

What about a clear humidity dome?

Well, that is the problem with me sometimes. My mind jumps to what I think instead of listening and thinking about the words.

That is a question that I can answer, just not now. I will grow some basil under a clear dome compare it to the weighted method and present the results here.

The Best Way to Grow Basil Microgreens

Right now, I’m going to say using the weighted blackout method. Because I have written an article about how to grow basil microgreens I will only outline the procedure here and you can refer to the other article for more details if you’d like.

You can read How to Grow Basil Microgreens by clicking the link.

How to Grow Basil Microgreens

You will need the following. For more details on the equipment, supplies, and how to go about planting microgreens, check out my free video Microgreen Growing Course.

  • A planting and watering tray – any size will work.
  • Basil Seed – The Home Microgreens Store carries several varieties of basil at competitive prices.
  • Potting Mix – Basil grows best on a potting mix because they are a mucilaginous seed.
  • Tray Separator – to cover up the seeds and place the weight on them.
  • Weight – 2-1/2 to 10 pounds depending on the size of the tray.
  • Shaker bottle or spouted measuring cup to spread the seeds.
  • Spray bottle & water – to wet the potting mix and seeds (not to water).
  • Artificial Light – unless you have an area that receives a good 12 hours of sunlight you will need light.

Procedure to Grow Basil Microgreens

All basil microgreen seeds grow the same way excluding how long until they are ready to harvest. So this procedure will work for any variety.

  • Fill the planting tray with potting mix. The planting tray will have holes in the bottom.
  • Level the potting mix and tamp it smooth. A smooth surface makes it easier to space the seeds and not have them roll into divots. A good potting mix will not compact too densely, so you can tamp it down.
  • Place the planting tray in the watering tray (no holes and dry).
  • Use the spray bottle and wet the surface of the soil. You do not need to wet the whole depth of the soil. Only the top 1/3 of the total thickness. Too much wetness to begin with is why most people have problems with mold.
  • Place the seed into the shaker bottle or whatever you are going to use to spread the seeds. How much seed?
    You can go to the following articles and use the calculators to find the right amount of seed for your size tray.

Seed by the Gram

Seed by the Teaspoon

  • Spread the seed on top of the potting mix as evenly as you can. Don’t drive yourself nuts trying to be perfect, but try not to clump the seeds in any one spot.
  • Mist the seeds with the spray bottle to wet them. In about 20 seconds you will see a white gel form around the seed. This is the mucilaginous gel and is the reason soil works best.
  • Carefully place the tray separator on the seeds and place the tray on a shelf or somewhere it won’t be disturbed for 5 or 6 days.
  • Place the weight on top of the tray separator. See this article for how much weight.
  • Leave them alone for 5 days, don’t upset them, they are germinating and very fragile. Look at them after 5 days to see how they are doing. If the tray was completely covered you shouldn’t have to re-mist them.
  • if they look like the ones below, they are ready to go under the light. If not, replace the tray separator and weight for another day or two.
basil microgreens 6 days after planting in Hm potting mix and miracle gro potting mix
  • Now is the time to water them for the first time. But not over the top. Use the watering tray. How much water will depend on the size tray. I have a whole article focused on watering. Click the link to see my procedure for watering microgreens.
  • Place them under the lights. How far the lights are above the plants depends on the strength of the lights. For LED shop lights, 4 to 6 inches is good. For stronger LED grow lights, 12 to 18 inches will work. (I have an article in process for more details). For any other type of light, throw them away and get LEDs.
  • Water them only when they are nearly dry, refer to the watering article linked above. Microgreens do not need water on a schedule. They need water when they need water not every other day or every third day.
  • In 24 to 30 days your basil microgreens will be ready to harvest! Like the Lemon Basil below.

Or the Dark Opal Basil shown below.

Are You Ready to Grow Basil Microgreens?

If you are, be sure to use the weighted blackout method. The Free Home Microgreens Basic Grow Video Course will show you all the equipment, supplies, and steps you need to grow beautiful trays of microgreens!

Home Microgreens Store

The Home Microgreens Store carries several different varieties of basil seeds in many different size packets and bags!

Free PDF Grow Guide

If you don’t want to register for the free microgreen grow course, I also have a free pdf guide that shows how to grow microgreens.


  • 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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