Why Microgreen Seed Density is Important

Why Microgreen Seed Density is Important

There are many reasons why microgreen seed density is important. We'll touch on those reasons below. 

But first, the start of a short story, the reason that this website exists is because of the topic of microgreen seed density.

When we started growing microgreens, we hadn't a clue on how many seeds to sow. So, like everyone else, we searched Google. From the search results, we ran into two issues. 

why microgreen seed density is important

These are Borage microgreen seeds. They look like they are sown too lightly for microgreens. However, Borage grows to a larger microgreen and needs space for optimal growth.

The first issue is the vagueness.

Most of the Google results contained information aimed at commercial growers, those that want to grow microgreens for profit. The articles suggested we add teaspoons or tablespoons of seed (regardless of variety) to 10- by 20-inch trays.

They provided no method to calculate how many seeds to use on smaller trays.

The second issue is way too many seeds!

The one calculator we did find that calculated the amount of seeds to use based on tray area suggested why too many seeds. The soil surface was almost entirely covered when we used the calculators suggested amount of seeds.

This didn't seem right, or reasonable. The story will continue after we discuss the problems caused by poor seeding density.

For that reason, we made our own online calculator based on data from our own seed growing trials. 

Want to Know the Ideal Seeding Density?

Go to this article with an embedded easy to use microgreen seed calculator.

Microgreen Seed Density

You can throw any amount of microgreen seed on a soil mix and microgreens will grow.

But will those microgreens be the healthiest and most nutritious plants possible without wasting space, soil, and time?

Isn't that what we as home microgreen growers want? Nutritious plants and economically feasible plantings.

Let's see why seeding density is so important?

Low Seed Density

Well, first talk about a low seed density.

Too few seeds mean your tray won't have as many microgreens growing in the tray. In effect, you've wasted your time, electricity, and soil volume. It will cost you more money and time.

Now, none of the supplies are pricey, but planting at a low seeding density makes each tray of microgreens more expensive.

I don't think any of us want to throw away money.

High Seed Density

So if using too few microgreen seeds makes a tray cost more, then adding more seed will make each tray cost less.

That's good, right? Not necessarily.

Too many seeds mean too many plants in the tray that can cause a couple of problems.

Problem One

Crowded plants cause stunted growth. Dense planting doesn't allow each plant to get the light they need to thrive.

Ok, we know microgreens are meant to grow close together. However, each plant needs room to acquire the light they need to generate energy to produce vitamins.

Many internet sources say all of the nutrition in microgreens come from within the seed. We call BS on that. We will publish an article on this subject once we do more research. 

Take a look at the Cinnamon Basil microgreens below (you can expand it by clicking on the image).

over dense microgreen tray

The seeding density of this basil tray is over planted. Notice how small the leaves are in the middle of the tray compared to those that have room to grow.

The leaves in the middle of the tray are less than half the size as those on the outside. To some extent, this occurs in most microgreen trays, but not as extreme.

Those plants in the middle will not be as nutritious as the ones on the perimeter. 

Instead, plant same mass of seeds on two trays, and the microgreens from those two trays will have more nutritional value than those grown tightly on single tray.

Problem Two

The second problem with too densely planted microgreen seeds is the increased chance of damping-off disease or fungus growth

Both problems can be caused by the lack of air circulation around the plant stems, which gives the fungus spores the moisture they need to develop.

Damping off disease of microgreens

Damping off disease has taken down this tray of microgreens.

Commercial growers can install fans to improve air circulation across their microgreen trays. For the home grower, this is often not possible or is impractical.

Using the correct seeding density (plus bottom watering) will all but eliminate fungus and damping-off disease in microgreens grown in your home.

test photo for microgreens

Home Microgreens Store



Continue The Story

So those are the reasons why microgreen seed density is important.

  •  1. & 2. We want to produce the most nutritious microgreens possible while still getting the most out of our investment of time, resources, and money.
  • 3. Remove the possibility of disease and die-off of our microgreens.

To continue our story, when we searched for microgreen seeding density on the internet, we couldn't find detailed information.

So we decided to run tests ourselves. You can read more about how we found our ideal seeding densities in Calculating Microgreen Seed Density For Your Planting Trays.

Instead of keeping the information to ourselves, we decided to start this website and the Home Microgreens Store.

In the store, you can find microgreen seed packets containing the perfect number of seeds for the Home Microgreen Planting Trays, 5-inch by 5-inch trays, and 10-inch by 10-inch trays. 

If you use your own trays regardless of the size, the calculator in Microgreens Seed Calculator - Find the Perfect Seed Density will calculate the mass of microgreen seeds you need for the perfect seed density.

Then visit the Home Microgreens Store and purchase your microgreens seeds by the ounce or larger sizes.

If you are already growing microgreens, how do you determine your seeding density?

Drop us a comment below, we'd love to hear from you!

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  • Hi there, I’ve just started to grow microgreens as a hobby and found your seed density information extremely useful! I would like to grow commercially eventually and love the idea of having my own calculator like yours. How did you work out the different formulas etc for each tray size and seed? Thanks

    • We’re glad you found the calculator useful! We worked out the seed density by gathering and averaging information on how many seeds if each variety are in a unit mass. Then by testing, we figured out a rough calculation on how many seeds we need per square-inch. Then we took that number and calculated how much mass of seeds that number is for each variety, and from there we tested and changed mass based on the outcome of the plantings by trial and error. We also figured out, but have not published yet, that the shape and circumference of the growing container also change how many seeds should be planted due to the area outside the cylinder or square of the container.
      That’s the short of it. Looking to grow commercially? Currently, I’m creating a course for small-scale commercial growers. Stay tuned! Thank you for your kind words.


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