Microgreen Grow Like A Pro! - 2 (Reading time: 3 minutes)

microgreen 工作坊及課程

Highlight of this article:

  • Do I need to cover Microgreen seeds after sow?
  • The Weight-On-Top technique of growing Microgreen
  • The Black Out technique of growing Microgreen

In the first episode, we asked you to save at least two trays to grow microgreen, you will find out why in this article. Let us jump into the tips right away, and let us take you through the theory behind them!

Tips 1:Weight-On-Top Technique

During the seeding process, we often ask our gardeners to cover seeds with soil at approximately 2 times the diameter of a seed. The purpose of this is to:

  • Ensure water retention by surrounding seeds with moistened growing medium
  • Ensure seeds are firmly seated so that roots will grab the soil firmly later

With Microgreen, we consume their cotelydon, or cotelydon with the first pair of true leaf, thus we don't usually cover the seeds while sowing (Apart from species that comes in wrinkled seeds, such as Swiss Chard or Nasturtium). But this leads to another problem —— the seeds may dry out in its germination process. Drying out will slow down seed germination, also leading to non-uniform harvest, which is rather crucial to Microgreen harvest. To avoid seeds drying out, after sowing seeds on a soil bed with <5cm depth, we can place another identical tray on top of the seeding tray, then put extra weight on top accordingly (Image below):

microgreen 種植方法, How to grow microgreen

Using an identical tray to cover the seeding tray in this way, and place bricks, rocks, or water bottle for extra weight on top, but remember to place weight evenly on surface

If you cannot place an extra weight on top, we recommend you to at least adding the cover with another tray, to avoid drying out of the seeds. For seeds that are small and softer, such as Amaranthus, Basil, Lemon Basil, or Cress, they enjoy less weight on top, so a tray only is enough for them. An extra benefit of adding an identical tray is that the tray will stick away some nutshell, so it makes it easier for harvest too.

How to grow microgreens

Amaranthus, Basil, Lemon Basil, or Cress seeds are smaller and softer,  they enjoy less weight on top, so a tray only is enough

Now, we also suggested that your trays should be opague. Why? Find out from our next tips!

Tips 2:Black Out Technique

This is probably the concept that is most different from growing other plants. 
As gardeners we do not want any leggy seedlings, which is caused by lack of sunlight. With Microgreens, in order to make harvesting of cotelydon and first set of true leaves easier, we deliberately create leggy seedlings with a technique called Black Out.

Timing is the most important. Let us explain this by showing you the images of the process.

microgreen 如何種植 小撇步,How to grow microgreen

1. When you see the root hair starting to form, you can start the Black Out process

microgreen 如何種植 小撇步,How to grow microgreen
2. The easiest way to do Black Out, is to reverse the tray on top as a lid, creating a micro dark environment for your Microgreens

microgreen 如何種植 小撇步,How to grow microgreen

3. When your Microgreen enter the process of Black Out, it is high possible that it is also time for you to start bottom-watering. You will see roots starting to come out from drainage point of seeding tray, and the white roots are the evident of a healthy plant. To understand the principles of watering, check out our first episode of this series

microgreen 如何種植 小撇步,How to grow microgreen

4. When your Microgreen reaches the expected height, you can remove the lid to end the Black Out process. Bringing back the light will allow photosynthesis, and your Microgreen will return to its colour

To conclude

We know the process may sound complicated, but don't get overwhelmed!
After growing Microgreen yourself for 2 to 3 times, you will know how to observe and do the process above naturally. Now that you got the tips, it is only about watering the right way, which is in this article.

Below is a table details on soil on top, Weight-On-Top days and Black Out days for each Microgreen varieties. Taking reference is useful, but ultimately they are affected by the temperature, humidity, and the condition of each batch of seeds. So as we said, the most important is to OBSERVE, OBSERVE and OBSERVE!

Varieties Soil on top Days of
Weight On Top

Days of
Black Out

Amaranthus No.4 No Tray only = 3 Days 2 Days
Lemon Basil No Tray only = 3 Days 3 Days
Sweet Basil No Tray only = 3 Days 3 Days
Thai Basil No Tray only = 3 Days 3 Days
Cress No Tray only = 2 Days 2 Days
Kale - Kale No.1 No 3 Days 2 Days
Kale - Kalebration mix No 3 Days 2 Days
Mustard - Fringed No 3 Days 2 Days
Mustard - Red Giant No 3 Days 2 Days
Mizuna - Red Empire No 3 Days 2 Days
Mizuna - Red Knight No 3 Days 2 Days
Nasturtium No.1 Yes 0 Days 0 Days
Pea No.21 No 3 Days 2 Days
Radish - No.31 No 3 Days 1 Day
Rocket - Salad No 3 Days 2 Days
Sage No 3 Days 2 Days
Swiss Chard Rainbow Yes 8 Days 3 Days
Swiss Chard Red Yes 8 Days 3 Days
Sunflower No.1 No 5 Days 2 Days


In the next episode, we will looking into problems of mold that is very common with Microgreen. Stay tuned with us!

More on this:

Microgreen Grow Like A Pro! - 1 (Reading time: 5 minutes)

Microgreen Grow Like A Pro! - 3 (Reading time: 3 minutes)



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