Grow Methods for Microgreens in Aquaponics Update

Grow Mats

Have you ever had an idea that you were almost sure was going to work and then....? The "and then" part is where your excitement turns to frustration and you begin to question your fabulous idea. I'm sure you can guess by now my fabulous idea was to use grow mats for the microgreens, as I mentioned in my previous blog post, "Grow Methods for Micogreens in Aquaponics". I really thought these things were going to work great. In theory they should…however, as we are learning, Aquaponics is whole different beast.

There were two types of grow mats we experimented with…BioStrate Microgreen Grow Roll - 9"W x 120'L and Micro-Mats Hydroponic Grow Pads. The Micro-Mats were great because they were pre-cut; however, they were more expensive and they just crumbled apart with being wet in the aquaponics system. So those had to go and we were left with the BrioStrate Grow Roll…which I believe is made of felt. 

Grow Mats have been known for hydroponic growing; however, in an aquaponics system (at least the flood and drain system that we have) as soon as the water floods the holey trays with the mat inlay, the water moves the seeds enough to cause clumping and uneven growth. The radish microgreens didn’t seems to have a huge problem with this; however, this seems to be a big problem with the small broccoli microgreens and a bit of a problem with the large pea shoot seeds. See pics below. This is problem #1. Problem #1 leads me to problem # 2.

I wish I could report the microgreens were doing awesome with my idea…unfortunately, the microgreens are just not growing as lush and healthy as they were when we were growing in the hydroclay in the grow trays. We also experimented with putting the lava rock in the grow trays and then planting. The grow trays were a must due to the fact we were left with way too many roots to just leave behind in our grow beds, which can lead to other problems. With the hydroclay pebbles and the lava rock the pea shoots were flourishing…which just does not seem to be happening with grow mats (see comparison pic below).

Problem #3…mold..yuck! We have not been able to harvest any radish microgreens yet due to mold. They look beautiful and ready to eat; however…when you take a closer look there appears to be white mold and little black dots on the stems. Plus, the roots look water-saturated, brown and unhealthy. There are little tiny root hairs that grow with the microgreens…we first thought this was mold; however, this turned out to be completely normal. I have to give credit to “Mr. Martian” to first figuring it out. According to Epic Gardening, “There is a BIG difference between mold and root hairs, which are concentrated around the main root of the seed and are very beneficial for a plant at the beginning of its life. You will find that white mold looks like a spiderweb crawling across the surface of the growing media” ( The spiderweb appears to be happening on our radish and broccoli microgreens…but not our pea shoots, thank you Jesus!

My theory with the mold is two-fold. They are taking too long to grow with the cold and are sitting in the bed for too long. The broccoli microgreens take much longer to grow and the mold problem is more prolific in these tiny greens. My other theory is in the rock they had more air flow between the seeds and with the mats they are just clumped together sitting in water. Planting too many seeds in a grow tray can also cause mold issues so I am experimenting with decreasing the amount of seed I use. My other experiment of choice is grapefruit seed extract. I have been reading about this and thought I should give it a go. I experimented with a dilution of 2 drops grapefruit seed extract to 2 cups sprayed directly on the radish seeds in the tray. I’ll have to keep you posted to see it I notice a difference. For more info on grapefruit seed extract check out

I think we may be back to square one. As soon as Mr. Martian gets home tonight I’m going to run some ideas past him…including going back to the hydroclay rock method since it worked so well. Hopefully I can put his engineer mind to work;). We are just going to have to figure out a way to wash all those rocks, as this is the main reason we decided to switch over to grow mats…so any suggestions welcome:). I also believe the rocks helped to stabilize the seeds and provide more air between them for better growth. I believe God gave us the answer to begin with…we just needed to listen…go figure;). I also believe through our trial we are better able to refine our practice to grow beautiful flourishing microgreens. God has great plans for our aquaponics journey…we just need to follow His plan. “Come, follow me,” Jesus said, “and I will make you fishers of men.” At once they left their nets and followed Him (Matthew 4:19-20).

He has great plans for all us! It may be hard but "Lord, I will choose to follow you". 

Scripture for thought...Matthew 16:24-28; Jeremiah 29:11

Odoo - Sample 1 for three columns

Clumping Broccoli Microgreens


Odoo - Sample 2 for three columns

Clumping Pea Shoots 


Odoo - Sample 3 for three columns

Growth Difference Between Grow Mats (right) and Grow Rock Media

Grow rock media has been in the bed longer and had more time to grow...