White mustard seeds placed on the top of the soil

Source of the photo: 
BME ABÉT
Author of the description: 
VE

White mustard seeds placed on the top of the soil: 20 seeds placed  at equal distance from each other.

Source of description: 

Feigl, V. Hungarian version of the description of the Sinapis Alba test: https://www.enfo.hu/keptar/3700