Using Liquid Organic Fertilizer: Grow Mats For Microgreens, Part 2

This is the second of three articles on using Terrafibre™ hemp mats for growing microgreens. It’s also the first of two articles on a liquid organic fertilizer called Ocean Solution.

The video below shows the test results we ran growing Red Acre Cabbage microgreens. We grew four trays, two using Terrafibre™ hemp mats and two using Home Microgreens Potting Mix.

In the first article and video, Grow Mats For Microgreens – Growing With Terrafibre Hemp Mats – Part 1; we saw that cabbage microgreens grew better in the potting mix.

However, as mentioned, the hemp mats have no added nutrients, while the potting mix does.

This article aims to see if adding a liquid organic fertilizer when watering will improve growth in the microgreens grown on the Terrafibre™ mats.

The video explains the test and shows the surprising results!

Video: Using a Liquid Organic Fertilizer & Fiber Mat to Grow Microgreens

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What Liquid Organic Fertilizer?

In the test, we used a liquid organic fertilizer called Ocean Solution.

This ORMI-certified organic fertilizer is interesting because it is derived from deep ocean water.

home microgreens sells seeds

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Ocean water contains all of the 90 naturally occurring elements. If the desalination process used to reduce the product’s salinity retains all of those elements. It should also provide microgreens with all they need to grow.

That’s the thought process, anyway.

We will vet Ocean Solution a bit more in an upcoming article. We will further explain how we used liquid organic fertilizer in the article.

Our Grow Mat verse Soil verse Organic Fertilizer Test

We started four trays of Red Acre Cabbage microgreen seeds sowing 3.5 grams on two Terrafibre hemp mats and two trays of Home Microgreens Potting Mix.

four trays of microgreens

We started them the same as we did in Part 1 of this grow mat for the microgreens series. All four trays are in the blackout with weight on top of the lids.

Why 4 Trays of Microgreens?

We grew four trays of microgreens to test how well Ocean Solution performs with hemp mats and test if the liquid organic fertilizer improves microgreens grown on soil.

The test will also confirm the results from Part 1 of this series.

Below is a photo of the four trays coming out of the blackout.

four trays of red cabbage microgreens

The four trays are from left to right, Terrafibre, HM soil, Terrafibre, HM soil. The two left trays will be watered with Ocean Solution, and the two right trays with plain tap water.

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

Here’s Where We Diverge From Part 1

In the video, the process is explained a bit more. Still, in short, the two trays on the left will be watered with Ocean Solution liquid organic fertilizer. The two right trays will be watered with plain tap water.

In each set of trays, the tray on the left is Terrafibre™, and the right trays are filled with Home Microgreens Potting Mix. 

Each Home Microgreen Planting Tray is placed in a Home Microgreens Watering Tray.  

The trays containing the hemp matting are elevated above the bottom of the watering tray by pieces of broken plastic clothes hangers. This allows the mat to soak up water but not flood the mat.

The trays of microgreens are watered once they come out of the blackout (those above have already been watered) and checked daily to see if they need more water.

Do You Have a Pinterest Microgreen Board?

If not, why not start one! Use this pin as the first or add to your existing boards.

ocean solution a liquid organic fertilizer

Ocean Solution Liquid Organic Fertilizer

Ocean solution is a clear concentrated liquid certified organic fertilizer with an analysis of 2-0-3. As with most organic fertilizers, don’t worry too much about the NPK analysis. Results are what we are looking for. 

Dilution Rate for Ocean Solution

Since the fertilizer is concentrated, it needs to be diluted before application. 

Ocean solution can be used in many different applications. For hydroponic growing – basically, what we are doing with the mats – the recommended dilution is 0.5- to 0.75-ounces of Ocean Solution to a gallon of R.O. water.

Just forget you read R.O. water because we did.

We only used tap water.

Maybe we could have gotten some distilled water, but, yeah, that seemed like a wasted trip to the store. I’m not positive what the conductivity of our tap water is here. We’ll explain more about the fertilizer solution’s conductivity and E.C in the dedicated Ocean Solution article.

Maybe, or add it to the article after once we get a good conductivity meter.

I am measuring out 5 mL of Ocean Solution to add to 20-ounces of water.

Anyway, we didn’t need a gallon of fertilizer, maybe 20-ounces.

There is about 592 mL in 20 ounces, 3785 mL in a gallon, and 22.2 mL in 0.75 ounces.

Do the math, X/592 = 22.2/3785, and solving for X gives us 3.5-mL of concentrate for 20-ounces of water. 

We figured 5 mL was close enough. So that’s what we used. To 20-ounces of water, we added 5-mL of Ocean Solution.

Rather Listen than Read?

If you’d like to listen to a summary of this article a new episode of the Microgreen Podcast will be published soon. It will include a summary of this very article and other interesting facts that aren’t published herein. 

 Click here to visit the Podcast and subscribe with your favorite podcast provider!

Adding Fertilizer To The Trays

To fertilize the trays, we added about a quarter-inch of water to the bottom of the watering trays and lowered the planting tray into it. The trays with Terrafibre™ matting settle down onto the broken clothes hangers we placed in the bottom of the watering tray.

The mats still soak up the water, and some of the red cabbage microgreen roots have already grown down through the holes in the planting tray to access the water. 

Water is added to the trays when they’re removed from the blackout period. And anytime after they feel or look dry. Microgreens are only bottom watered, never from the top once they’ve germinated. 

Day 1 Surprise!

By day 1, we mean the first day after we fertilized the microgreens.

We were so surprised!

Not surprised by how green (or purple) the microgreens became; that happens every time the lights are turned on for the first time. 

But instead, by the growth of the microgreens on the Terrafibre™ and Ocean Solution tray when compared to the one that wasn’t fertilized. Compare the leftmost tray to the middle-right tray.

What a difference!

microgreens grown with liquid organic fertilizer

One day under the lights, and one day with fertilizer added. Again, from left to right, Tray one is grown on Terrafibre and with Ocean Solution. The third tray to the right is Terrafibre watered with plain tap water.

Much more growth and larger leaf size!

I expected to see a difference at some point in the fertilized trays, but not after less than a day!

Notice there isn’t much difference between the trays of microgreens grown in soil. Those trays are from left to right, trays two and four.

Below is a closeup of the two Terrafibre™ trays. The liquid organic fertilizer Ocean Solution has been used to water the tray on the left (first image on mobile view). You can click the picture to expand it for better viewing.

using a liquid organic fertilizer
using plain water and no liquid organic fertilzer

Are You Looking For Microgreen Seeds and Supplies?

Home Microgreens online store sells reasonably priced microgreen seed packets with the perfect amount of seed for 1010, and Home Microgreens trays plus ounce, 1/4-pound, and pound bags.

We also carry our own microgreen soil and fiber mats for the home microgreen grower!

Does the Growth Rate Continue?

Absolutely it does.

why I now use a liquid organic fertilizer

The image was taken from the video (watch it for more information) above. The trays are in the same position. The two fertilized trays are on the left. 

Look at the difference between trays 1 and 3 (left to right). That’s amazing!

The Ocean Solution liquid organic fertilizer has at least tripled the size of the red cabbage microgreens grown on Terrafibre™ hemp matting. 

At first, I didn’t notice a difference between the fertilized and non-fertilized microgreens grown in soil, trays 2 and 4, respectfully.

But after looking at the images, the microgreens watered with Ocean Solution (tray 2) are a bit tighter and grown more densely together. While tray four might be a bit taller and the leaves slightly bigger are more open and have a looser dome. 

However, there isn’t much difference, and wouldn’t buy and use a fertilizer (added cost and steps) when growing in Home Microgreens Potting Mix. More on this later in the article. 

Comparing Terrafibre™ and Soil Using Fertilizer

The point of this article is to see if using a liquid organic fertilizer on microgreens sowed on Terrafibre™ will grow as well as microgreens grown on soil.

Let’s take the microgreens grown on the hemp mat out of the deep tray and raise them up to the same level as the soil to compare their growth.

microgreens grown with a liquid organic fertilizer

Not the best image, but you can see that the growth is very similar. The only difference is that the microgreens grown on the hemp (left tray) have been forced to grow more upright due to the sides of the tray. 

This crowding could also cause slightly smaller leaves on the microgreens grown on the hemp mat.

Overall, growing microgreens (those that can be grown on mats) on Terrafibre™ hemp mats using a liquid organic fertilizer like Ocean Solution is as good as growing on soil. 

Conclusions & Recommendations From This Test

Hemp mats, such as Terrafibre™, are an excellent alternative to growing microgreens on soil when a liquid organic fertilizer is added to the water. 

Adding Ocean Solution to the watering tray had an obvious and significant benefit to the microgreens growing on the hemp mat. 

Ocean Solution did not appear to add many benefits to microgreens grown on Home Microgreens Potting Mix. However, it might work well on the other potting mixes we have tried and did not meet our potting mix’s success.

We plan to test pure coconut coir with Ocean Solution to see if microgreens will grow better and calculate if there is a cost-saving when combining these two products.

We will post a link here when that article is published, or you can get alerted by getting our updates.

You can purchase either of these products using the links below.

Terrafibre™ can be purchased in the Home Microgreens Store pre-cut for the Home Microgreens Tray, 1010, 1020 trays, and by the linear foot.  

Ocean Solution liquid organic fertilizer works wonders on microgreens grown on hemp and probably other mats and nutrient poor grow media.

At first look the price seems expensive, but to grow two trays of microgreens we only used 5 mL. So, the bottle shown would grow around 190 trays!

About 15-cents a tray. 

We will try to work out a deal or discount with the makers of Ocean Solution.


  • 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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