Microgreen herbs are an expensive endeavour. Herbs grown from seeds grow very slowly because they have very small seeds relative to other plants. Their growth will begin to accelarate three to four weeks after seeding, which is overgrown by microgreen standards.
Basil is the only herb microgreen grown because their seeds are relatively inexpensive in bulk, especially thai basil. For this growing guide, I'm growing sweet basil, the species of basil most commonly found in the grocery store.
Basil is enriched in vitamin K and Vitamin A, and is also a rich source of manganese. Moreover, basil is full of omega-3 fatty acids and eugenol oil, which has been demonstrated to reduce cardiovascular disease and inflammation. Eugenol oil also has antimicrobial properties, which affects the health of the microbiome. However, there is no data on the concentration of omega-3 fatty acids or eugenol oil in basil microgreens.
Basil microgreens are highly enriched in antioxidants. In fact, basil microgreens have more antioxidant capacity than kale microgreens. Antioxidants prevent cancer. Basil is unique because it's one of the few microgreens where evidence of anti-cancer and anti-inflammatory effects exists.
I use a peat based medium for growing basil, where I mix with 10% vermiculite by weight. Vermiculite provides both aeration and moisture availability, which helps buffer the time in between watering and maintain healthier roots. Make sure to vigorously mix the medium with water prior to use. Dry peat moss floats on water, which makes it difficult to moisten when dry.
In addition to vermiculite, I add fertilizer to a concentration of 0.5%. This helps basil sustain growth past 2 weeks.
Soaking the seeds is not necessary because it doesn't improve germination rates and increases seed clumping. The moisture required for germination should be provided by the growing medium.
Basil should be seeded at 25 g per square meter or 1/32th oz per square foot. Higher seeding rates increases the risk stunted growth and fungal infections.
Cover the seeds with either a humidity dome for the first 3 days or 1/8th inch of growing medium.
Allow the basil to dry in between watering, which translates to 2 to 3 times per week depending on the humidity. Basil microgreens can be harvested at two weeks after seeding, at which point the first pair of true leafs emerge.
To harvest the basil microgreens, use a sharp pair of scissors to cut at the base and wash off the remaining growing medium. Two week old basil would not be taller than 1 cm or 1/4 inch.
You can save some of the basil for everyday kitchen use. Let the basil overgrow for 1-2 weeks after harvest and transplant to a bigger container.
Basil is easly propagated clonally from clippings. You can either grow basil clippings on water or directly on growing medium. Clonal propagation is faster than growing from seed because of its larger leaf surface allows for more photosynthesis. This makes it easy for you to have a large supply of basil.
I am the author of this website and owner of growyourmicrogreens.com. I am an hobbyist gardener and a passionate scientist. I was trained as a scientist in the Molecular Genetics program in University of Toronto, where I received my Masters of Science and published a journal article.