How to Grow Shiso Microgreens in 6 Easy Steps

If you’re looking for a fun and unexpected plant to add to your microgreens garden, why not try shiso? Shiso (Perilla frutescens) is an herb that’s very popular in Japanese cuisine but doesn’t get enough attention stateside. It takes a few months to grow a mature shiso plant, but shiso microgreens can be ready in as little as eight days! They’re definitely worth a shot, especially with how much flavor is at stake.

Shiso is in the mint family and is often called perilla mint. That doesn’t mean it’s going to taste like toothpaste, though. Yes, they have some mint flavor, but mature shiso plants also feature a blend of flavors from zingy-fresh cilantro and basil to warm cloves and cinnamon.

Green shiso microgreens are a bit more simplistic in flavor, but no less delicious. They’re often described as having an anise and slightly sweet licorice flavor, which is a fun garnish.

Shiso microgreens are also great for adding a splash of color to your food and microgreens herb garden. Some varieties have deep red-purple tones that have earned it the nickname “beefsteak plant”.

This plant is also quite colorful when it comes to nutrients. Green shiso is loaded with vitamins A, C, and K, iron, fiber, calcium, and potassium. It has even been used to treat arthritis, eczema, and cold symptoms.

Shiso microgreens may seem unfamiliar and a bit daunting, but they’re very easy to grow. They follow nearly the same growing process as most microgreens and use the same materials. So, whether you’re new to microgreen gardening or an old hand, you’ll have no problem growing a tasty crop of shiso microgreens.

What You’ll Need

Here are the supplies you’ll need to set up your shiso microgreen garden. You’ll need the same materials for most microgreens as the process to grow them is similar.

Seeds

There are several varieties of shiso that have varying characteristics in microgreens. Your basic green shiso will have silvery green leaves. Red shiso microgreens have lovely, deep purple and red leaves.

Or, if you’re after something even fancier, bicolor and variegated shiso is a mix of the two colors. For instance, Botanical Interests has a great green and red shiso variety! Any of these will make a tasty bunch of shiso microgreens.

Containers

The growing containers for micro greens need to be wide and shallow. 10×20 inches is a pretty standard size that only needs about an ounce of green shiso seed. Each crop needs two growing trays, one of which has drainage holes. The other one has to be solid because we’ll be using it for watering later. 

Growing Medium

Use a fine-grained soil mix that consistently provides moisture to the seed like a seed starter mix. There are also soil-less options, such as coconut coir or vermiculite, but shiso seeds don’t grow well in fully hydroponic systems. Some growing medium should be used.

Grow Lights

Shiso microgreens thrive with consistent light. Using a grow light is ideal, as it allows you to maintain a consistent schedule of 12 or more hours of light daily. Position the grow light close to the microgreen tray, ensuring it provides even coverage across all the plants.

If you don’t already have grow lights, consider the Epic shop’s options. These lights are excellent for growing microgreens indoors.

Alternatively, you can place the tray near a sunny windowsill. Be sure to rotate the tray regularly to ensure the microgreens receive even sunlight exposure.

Extras

In colder regions, a heating mat will help keep the seeds warm. You will also need scissors or pruners, a misting bottle, and a small weight of up to five pounds.

How to Grow Shiso Microgreens

Once you have a good setup, it’ll be easy to try out all sorts of micro greens. Some gardeners stock their microgreens on a wire rack while others spread out growing trays on their kitchen counters. As you practice growing them, you’ll get a sense for what does and doesn’t work in your own garden.

Step 1: Soak

Shiso seeds are round and textured with a thick hull. Though they’ll germinate without soaking, extra moisture will considerably speed up the process. Soak your shiso seeds in cold water for at least two to four hours before sowing.

Step 2: Plant

While your green or purple shiso seeds are soaking, grab your sprouting trays and soil. Fill the tray with drainage holes to just below the rim. Smooth out the surface and remove any large debris from the soil.

Then, you can drain the green shiso seeds and spread them across the tray. They should be crowded together without touching or overlapping. Though we want a dense mat of microgreens, we also have to make room for good airflow between the sprouts.

Step 3: Cover

Give your seeds a good watering with the spray bottle. Then, instead of covering them with soil, place the holeless tray directly on top of the seeds. To keep the cover in place and encourage even growth, place a small weight on top. It could be a rock, book, or anything else under five pounds. 

To boost the germination rate even more, place a heating mat under the seeding tray. Keep the soil at around 75°F (24°C) until at least half of the seeds have germinated (remember that too much heat can inhibit germination).

Step 4: Grow

Once planted and covered, your green shiso seeds are officially in the blackout period. This should last as long as it takes for most seeds to germinate, plus a couple of days for growth. Shiso seeds germinate pretty well, so the blackout period will last for three to five days, depending on the variety. 

When your shiso sprouts are ready for some sunlight, they’ll collectively push up the cover tray and weight. Remove the cover and position the tray about a foot under the grow lights. Turn on the lights for at least six to nine hours a day.

Your shiso microgreens will probably be thirsty by now. To avoid bacterial growth in the purple leaves, water them from the bottom of the tray instead of on top.

You can reuse the solid tray for this by filling it with a bit of water and setting the grow tray inside it. After 10-15 minutes, separate the trays. Repeat this bottom-watering process whenever the soil surface starts to dry out.

Step 5: Harvest

Perilla mint microgreens are usually harvested after the first true leaves grow in. These serrated leaves will grow in after the round cotyledons have unfolded.

The older each beefsteak plant gets, the more it’ll start to get the spicy mint and basil flavor that’s present when shiso reaches maturity. However, you’ll need to harvest them before the microgreens outgrow their shallow tray. Aim for collecting your greens before they exceed two to three inches tall.

To harvest shiso microgreens, clip the pale green stems in bunches. Kitchen shears are the easiest tool for this, but you can also use a clean knife. Shiso microgreens have the best flavor when fresh, so you may want to harvest as needed. Just be sure not to wait too long!

Green shiso microgreens are unlikely to regrow after a harvest, so you can compost the soil and start a new crop right away.

Before planting anything new though, thoroughly wash the trays and any tools used. For your next crop, you could try some fennel or sorrel microgreens (or give purple shiso another go!). 

Step 6: Store

Eat your freshly harvested shiso microgreens raw. They make a great garnish for spicy dishes, sushi, fish, teas, and sweet treats. Shiso’s unique cinnamon, anise, mint, and basil flavor will be fun to try with many different recipes, whether entreé or dessert.

Leftover green shiso microgreens should be stored in a sealed container in the refrigerator.

They have a shelf life of about a week but are best eaten as soon as possible. To help preserve freshness, wrap the shiso microgreens in a paper towel in their container. The towel will absorb excess moisture and can easily be switched out as needed.

Frequently Asked Questions