How to grow shiso (perilla)
I posted a photo of my sprouted shiso seeds on Instagram this morning, which led to several people asking how to grow it. Although I've written about growing shiso a couple of times before, I have never described the procedure. So, here it is!
What is shiso?
Shiso (紫蘇）is one of the most commonly used herbs in Japanese cooking, and the best one to grow if you have any interest in Japanese food. It's an annual plant. The botanical name is Perilla frutescens var. crispa.
What kind of shiso to plant?
There are basically two types of shiso: green and red. Red shiso (赤じそ、akajiso) is usually used to make umeboshi pickled plums and some other kinds of pickles, but not much else. They can't be eaten raw because they are rather bitter, so they need to be salted, blanched, and whatnot. I usually don't plant red shiso at all unless I want one for contrast with my green shiso - they are very pretty together.
Green shiso (青しそ, ao-jiso) is the one to plant for all kinds of uses: as garnish, as an onigiri wrap, shredded and used as yakumi (extra seasoning if you will) with cold noodles or tofu; as pretty dividers in your bentos, in salads and a lot more. Shiso has a slightly minty taste, and makes a very nice pesto. Green shiso leaves are also called ohba （大葉), which just means 'big leaf'.
The sprouts of eater are used as delicate garnishes. Even the seed pods are eaten - salted and preserved, or as tempura. The leaves can be made into tempura too - shiso leaf tempura is crunchy and fragrant.
There's another type of perilla used for culinary purposes: Perilla frutescens var. japonica, called egoma in Japan and deul-ggeh in Korean (thanks Eric). This is not shiso, and has smooth leaves rather than the rather bumpy frilly leaves of shiso. The seeds are used to make a kind of oil that's supposed to be very good for you.
Where to get shiso seeds
You may be able to just buy shiso seeds these days at your local garden center, but if not, try one of the following:
- Try looking under the botanical name for shiso, Perilla frutescens var. crispa. Some seed catalogs may carry it as an ornamental plant rather than a herb, so look in that section. An even older western name for it is the beefsteak plant (goodness knows why) but that is out of vogue now.
- The sources for Japanese herb and vegatable seeds listed on this page should still be ok.
How to sow shiso seeds
Shiso seeds are very tough and sturdy. You can just seed them in your garden where you want them to grow, but they may take a long time to germinate that way, perhaps 3 to 4 weeks, and quite a few of the seeds may fail. To ensure that most of your shiso seeds germinate, soak them in water for 24 hours before seeding. To sew those soaked seeds, I just pour them on the seed bed water and all. This way the seeds should germinate in 4-7 days or so.
You can sow shiso indoors to give them a start. I just sow them in Jiffy-7 pellets, as you can see in the photo up to; I sew as many Jiffy-7s as I want plants plus a couple extra, and snip away the extra seedlings as they grow. The seedlings can be used as garnish on salads, on cold tofu, and so on -- after all, seedlings and sprouts are the same thing.
Do not let the seeds dry out or you will delay germination even further. The packet of Japanese seeds I have recommends covering the seeds with a sheet of newspaper, and keeping that paper moist until the seeds germinate. (But, who has newspaper around these days? We don't...)
How many plants do you need?
Just one or two plants will give you enough leaves to use as garnish, or shredded on top of tofu, or eaten with cold soba noodles etc. Plant a few more if you want to make pesto or preserve the seed pods in some quantity. I am restricted to growing things in pots right now because our garden is still a pile of rubble basically, so I plan to have about 5-6 plants in pots. Shiso grows in pots quite happily although they rarely get to full height in them.
Climate and growing conditions
Shiso grows all over Japan, which ranges in climate from the Scandinavia-like Hokkaido to subtropical Okinawa. In temperate climates with mild winters it self-seeds pretty readily. My mother grew shiso in her garden on the North Shore of Long Island, New York (Zone 7) and her shiso self-seeded all over her vegetable patch.
Basically you can grow them as you would basil. They like well draining soil, although they grow in any kind of soil. They aren't too finicky about water - just water them well if they go dry or start to wilt. (Shiso grown in pots needs a lot of water.) They get to around 5 feet (150cm or so) tall. At the end of summer the flower buds form; you can let them flower and form seed pods, or clip them off to keep the leaves coming. Shiso flowers can be used as very pretty garnish on sashimi plates and so on.
The plants die back in winter, and may self-sow for you if you leave some seed pods on them.
Shiso leaves rarely get any kind of disease, and they aren't that attractive to most insects. Snails love them though so watch out for them.
I hope that answers your questions! I'll take pictures of my shiso plants this year as they grow. Here's hoping I don't kill them off ^_^; The next stage for my shiso is to transplant them to pots.