Growing Mustard Micro-greens Indoors - Light vs. No Light

We recently got some nice grow lights. To measure the effectiveness of these lights, we decided to do simple experiment. We grew some mustard microgreens in the shade and some under these lights. The results, although obvious, were nevertheless fascinating.

Gardening Exp #001

Title: Growing Mustard Micro-greens Indoors - Light vs. No Light

Aim: To observe the different in growth between two samples of mustard micro-greens grown indoors - one with overhead LED grow light and one without.

Expectation: The ones with LED Grow light turned on will fare better - how better and in what way is to be seen

Setup

• Location: Wakad, Pune, India
• Seeds: Locally available Black Mustard Seeds ( राई )
• Sowing Date: 2020-06-07 1730 +0530 IST, Sunday
• Harvest Date: 2020-06-13 2030 +0530 IST, Saturday (6 days later)
• Season: Beginning of monsoon
• Weather: In the evening at around 1900 hrs, the temperature used to be around 28 °C and Humidity at 70%
• Number of seeds: 1 Teaspoon full in each planter
• Placement and Illumination:
• Placed on 2 shelve unit located a few meters from nearest window inside the house
• Top Shelf: A set of another 3 planters without any grow light
• Bottom Shelf: A set of 3 planters with LED grow light turned on 24 hrs.
• Soil: Dry regular garden soil without any additives or supplements
• Water: Regular RO+UV filtered drinking water
• Watering Schedule:
• Watered around 1230 IST every day, initially the soil was dry so added more water on sowing day and the day after that, but decreased the quantity of water depending on the soil moisture
• 2020-06-07: On sowing date 170 mL in each planter
• 2020-06-08: Next day 85 mL in each planter
• 2020-06-09 to 2020-06-12: 60 mL in each planter
• 2020-06-13: No watering on day of harvest
• LED Grow Light Specs: 25 Watts Panel of a total of 75 LEDs (red:47, blue:19, white:3, UV:3, IR:3) bought from AliExpress here

Black Mustard Seeds

Indoor Setup for Exp #001 which ran for 6 days
Top shelf: 3 Planters, no light
Bottom shelf: 3 Planters, LED Grow Light left on for 24 hours

25 Watt LED Grow light panel with 75 LEDs of which
47 were red, 19 blue, 3 white, 3 UV and 3 IR

Layout of the LED Panel Purchased from Shop4793007 on AliExpress
https://www.aliexpress.com/item/32972881405.html

Daily Difference in Growths of the two samples

The photos were taking around 1900 hrs everyday (since the initial sowing was also done around evening)

1 day after sowing: Monday

A few seeds have started to germinate in both samples

2 days after sowing: Tuesday

More of the seeds have germinated by now

3 days after sowing (Wednesday)

Difference is clear by now. We see leaves in both samples but the one
receiving light are larger and more dense already.

4 days after sowing (Thursday)

The samples on the bottom shelves exposed to LED are healthier and flourishing.
Some of the saplings in the right most sample on the top shelf have
started rotting and there is a stench emanating from them.
This time we took the photo of the bottom shelf without the LED turned on to get a better picture.

Another photo of the top shelf. The stalks are taller than the ones of
bottom shelf and they are tilted towards the window to
capture whatever little light they are getting. 

5 days after sowing (Friday)

Photos of left most planters from both shelves.
Saplings in the one taken from top shelf are taller, have smaller leaves

and are tilted towards the window.
The saplings in the bottom shelf have larger leaves, have shorter stalks and grow straight up.

Photo of the right most planter. More of the saplings have rotted.

6 days after sowing (Harvest Day)

Just before harvest. Of course we only used the one grown under the
LED light for our sandwiches. The ones grown in dark were rotted and seemed unfit to eat - we did taste them tho!

Both micro-green samples are tall enough to easily cut using scissors without pulling up soil.

Summary

1. Germination Rates: The number of seeds that germinated seems to be equal in both samples.
2. Height: The micro-greens which were not exposed to LED grow light grow taller and tilted towards the window located a couple meters away. The ones having access to LED grow light were shorter but grow straight up
3. Leaves: The ones under the grow light fared better and have thicker, larger and more number of leaves.
4. Disease Resistance: Many of the saplings on the dark shelf were extremely tilted and fell down on the soil during watering and started to rot and created foul order.
5. Taste: The ones grown under the light were mildly more flavorful than the ones grown in the dark.

Harvest and Enjoy!