Artichoke Grow Guide
Artichokes have always been more of a fascination to me, something I’d wanted to experience up close, in person, and across the seasons. And that’s why I decided to plant them last year.
Truth be told, I bought the seeds in winter 2021, then forgot to sow them in 2022, so it took an extra year to remember they were in my possession and to time it all right.
This guide should give anyone growing in a cooler zone the skills and timing they need to get ‘chokes in summer.
About Artichokes
Artichokes are thistle-like perennial native to the Mediterranean that is a domesticated version of cardoon. It’s in the Aster family, so related to flowers including zinnias, sunflowers, cosmos, and prairie plants like black-eyed susans and New England asters. It puts out massive, sometimes 3’ long, leaves that are a silvery green, deeply veined and pointy. Some varieties can be a bit thorny, a nod to their cardoon heritage.
Like most perennials, it doesn’t usually flower the first year — and that’s why it’s often tricky to grow it in cold climates, zones 7 and colder, where it’s not winter hardy.
Varieties
There are lots of artichoke varieties out there, but I am listing just a few that are well-suited to colder climates. If you’re in a warmer zone, you have more variety to choose from. Imperial Star was the first such improved artichoke for northern climates, producing ‘chokes in the first year.
Wonder (F1) – High Mowing, patent utility variety
I’ve only grown Imperial Star, but I’d guess Tavor would produce similarly for me, given it’s an improved Imperial Star. Seeing as how most of these are open pollinated, I don’t see the need to purchase a hybrid variety, especially one that has a 20-year patent utility (read about that here).
Sowing Tips
Artichokes are cute little seedlings. They do need a good indoor head start — up to 12 weeks, but 8 is sufficient in my experience.
Sow them around the end of February in zone 3 or 4. There’s no need to sow them any sooner. I started ours on February 15 last year, and produced chokes by mid-July with some key cold exposure in the seedling stage. This year I’ll sow them in the end of February, along with my earliest flat of brassicas.
Sow seeds 1/4” deep in 2” soil blocks or the equivalent size pot. Although they need cold exposure to produce buds, they need warmth, like most everything else, to germinate, so be sure to have your seedling mat on once you sow them. They might be a little slow to germinate (over a week).
Potting Up
About 4-5 weeks after they’ve germinated, pot them up into 4” (newspaper or plastic) pots — or a pot of at least double the size they started out in. I know it’s time to pot my plants up when I am seeing a lot of roots coming out of my soil block. This will depend on a few things: how long you keep your lights on (read: how much the plants are photosynthesizing), how warm your grow space is, and how much nutrition the plants have access to. If there’s not enough light, it’s cool, or the soil lacks nutrients the plants will not grow as fast.
This should give them ample space and sufficient nutrition (be sure the soil mix has lots of compost mixed in) to get them ready for your garden bed.
I like to pot my seedlings up into a potting soil mix that is about 1/3 - 1/2 compost (pretty much for all seedlings). This eases the need to fertilize the seedlings.
Vernalization & Hardening Off
Cold vernalization is the process of exposing plants to cool temperatures to promote flowering. This sets their biological clock to think they’ve gone through winter and are now in their second year when they normally produce their crops/flower. In order for us northerners to grow artichokes as an annual, they need 10 consecutive days of cold exposure in spring before they are transplanted. This can happen anytime after germination and before transplanting, so consider your long term forecast carefully.
We were blessed last spring with a long cold stretch in both April and May. It felt too long, but once it warmed up it was summer. (Read: we sort of skipped spring.) I used those weeks in April to set my artichoke seedlings outside on the deck, protected from frost but exposed to temperatures in the 40s for a few weeks. If memory serves, I think it even was cool when I transplanted them. May was dreary and cool.
And here I thought I used newspaper pots, but clearly I used plastic pots for these seedlings!
This is exactly the kind of weather these plants require to fruit as an annual: they need to think they’ve just weathered a Mediterranean/Californian winter. Whether you get there by erecting a little tent on your deck or keeping them in your cooler garage for a 10 days or so, this is a required step to go beyond the gorgeous silvery foliage and achieve the crowning success that is an artichoke bud/flower.
Plant Spacing
If grown as a perennial, artichokes need spacing of 5’, and end up needing to be divided every few years.
As an annual, I planted ours 3’ apart with Thumbelina zinnia tucked in at the edge of the bed. It was a bit rambunctious, but I figured this isn’t like potatoes or carrots, main winter staple foods for us, so the interplanting was intentionally flower-forward.
Harvesting & Cooking
Harvesting artichokes is sort of like harvesting broccoli: you watch it grow and have to decide, is today the day it’s as large as it will get before the flower starts to separate, or can I push it one more day? And they are quite similar, both being flower buds we are consuming. You want to harvest them when they are tight heads. My biggest one was probably the size of a tennis ball.
You might get 3 or so large ones, and then, depending on the season and how much space you gave the plants, should get a few more smaller ones. Just like with broccoli, I suppose, where side shoots are smaller than the main head.
Clip the artichokes just below the flower bud, with about 1” of the stem attached.
Steam in a double boiler for about 40 minutes with some lemon juice mixed in to prevent browning. Enjoy with an aioli or butter as a dipping sauce for the petals.
