What are globe artichokes

Globe artichokes (Cynara scolymus) are the immature flowerbuds of a thistle family plant and grown for the delicious flesh at the bottoms of their bracts and the tender artichoke hearts. The plants are extremely ornamental with spiky, silvery foliage and flower stalks that grow 3 to 5 feet tall. Plant artichokes in vegetable gardens or flower borders; this is a perfect plant for edible landscaping. Most varieties yield 6 to 8 artichokes per plant, but some can produce up to 10.

Globe artichokes are hardy perennial plants in zones 7 to 10, but can be grown as annuals in colder regions that have a shorter growing season. If protected over the winter, they can also be grown as perennials in zones 5 and 6. You’ll find out more about my overwintering techniques below. You can also grow artichokes in containers to produce tender buds on sunny decks and patios. If you don’t harvest all the buds on your artichoke plants they’ll open into purple, thistle-like flowers which add bold color to the garden and attract bees and other pollinators.

The best site for growing artichokes

When growing artichokes it’s best to find a sunny garden bed with fertile, well-draining soil. The plants are adaptable to various soil conditions but are heavy feeders and produce best in lightly moist, nutrient-rich soils. I top my raised beds with 2 inches of compost or aged manure before planting. A greenhouse, polytunnel, or other sheltered growing space is ideal for growing artichokes as perennials in zones 6 and lower. For the overwintered artichoke plants in my polytunnel, I add compost annually around each plant as well as a slow release organic vegetable fertilizer.

Growing artichokes from seed

Growing artichokes from seeds isn’t difficult but it does take a few weeks longer than crops like tomatoes or peppers. I start the seeds indoors in trays and cell packs 12 weeks before my last frost date. Sow seeds 1/4 inch deep in pre-moistened potting mix. Expect the seedings to emerge in 10 to 14 days. The ideal temperature for germination is between 70 to 80 F (21 to 27 C). Once the seedlings are 2 to 3 inches tall, transplant them into 4 inch diameter pots. Set the seedlings into the garden once the soil temperature has reached 60 F (15 C). Slip each seedling from its pot and take a peek at the roots. If the taproot is circling around the bottom of the pot, gently straighten it out when you transplant. If transplanting earlier, cover the seedlings with row cover if frost threatens.

Gardeners in warm climates that have mild winters generally transplant artichoke seedlings in autumn. The plants set their buds in mid to late spring and they’re cut back to the ground once production has finished. Globe artichoke plants resprout in autumn and crop again the following spring.

If you don’t have the space or patience for growing artichokes from seed you may luck into some seedlings at a local nurseries. The downside to buying seedlings is that you won’t have as many varieties to choose from.

How to vernalize artichoke plants

For gardeners like me who live in cold climates, it’s necessary to take an extra step called vernalization. Vernalization is a technique that exposes seedlings to cool temperatures in order to stimulate budding. It essentially ‘tricks’ the plant into thinking it has been through a winter and is now a mature, second year plant.

‘Green Globe’ is a classic globe artichoke variety and is widely grown in regions with mild winters. It needs 4 to 5 weeks of vernalization to successfully produce buds the first year and can be unreliable for cold climate gardeners. Thanks to plant breeding we now have annual artichoke varieties like ‘Imperial Star’ and ‘Colorado Star’ that can be vernalized with less than 2 weeks of cool temperatures.

To vernalize artichoke seedlings, expose them to temperatures in the 45 to 50 F (7 to 10 C) range for about 10 to 12 days. Cover the pots or trays of seedlings with several layers of row cover if frost is in the forecast. After the vernalization period, transplant the seedlings into garden beds or containers. Keep row covers handy in case temperatures drop again. Space seedlings 2 feet apart and rows 4 feet apart.

Growing artichokes in garden beds

Consistent water is essential when growing artichokes so aim to maintain a lightly moist soil, particularly during active growth in spring and summer. Drought stressed plants produce fewer and smaller buds. Mulch with straw or shredded leaves to conserve moisture and reduce the need to water. I use a long handled watering wand to direct water right to the root zone. I also feed the plants every 3 to 4 weeks with a liquid organic vegetable fertilizer.

Pull any weeds that grow and keep an eye out for plant diseases and pests. My biggest issue is aphids and I inspect my plants every week for signs of aphids. If I spot any, I then check for beneficials like ladybugs or lacewings. When beneficial insects are present on the plants, I let them take care of the aphids. If no beneficials are present, I’ll spray the aphids with a hard jet of water from my hose to knock them from the plant. You can also use an insecticidal soap. Slugs and snails can also be an issue on artichokes and I hand pick any I spot on the plants.

Diseases like powdery mildew can also affect artichoke plants. Powdery mildew is generally an issue in the humid weather of mid to late summer. A serious case of powdery mildew can reduce yield. To reduce the occurrence of powdery mildew plant artichokes in full sun and space them properly to promote good air flow.

Growing artichokes in containers

Globe artichokes make excellent container plants when grown in large, deep pots which accommodate the sizeable root system. An 18 or 20 inch diameter pot works well as does a 20 gallon fabric grow bag. It’s also essential that the container offer adequate drainage so check the bottom of the pot for drainage holes. Fill it with a combination of high quality potting mix blended with compost. A ratio of 50:50 is ideal for artichokes. I also work in a slow release organic vegetable fertilizer to the growing media to ensure a steady supply of nutrients.

When to harvest artichokes

Harvest when the flower buds have reached maximum size and the bracts are still tight. The plants produce large primary buds on the main shoots first followed by smaller secondary buds on side shoots. Don’t wait to harvest as overmature buds turn tough and woody. If you’re not sure look at the lower bracts. If they’ve started to separate from the bud it’s perfect. Using hand pruners, cut the stem 3 to 4 inches below the base of the bud. Once a stem has finished producing secondary buds, cut it back to the base of the plant. This encourages new stems to grow.

If the bracts have begun to open and you’ve missed the optimum harvest window leave the bud to flower. As a member of the thistle family, artichoke flowers are very similar to thistles and have large purple blooms that attract bees and other pollinators to the garden. They also make long-lived cut flowers.

How to overwinter artichokes

For years I grew artichokes as annual plants in my garden beds. However using garden covers like cold frames and my polytunnel has made a huge difference to my artichoke crop. I now have perennial artichoke plants that emerge each spring. The key is to deep mulch the plants in late autumn with 12 to 18 inches of straw. Damage to artichoke plants can occur when temperatures drop below 25 F (-4 C), but a layer of mulch offers insulation. To mulch artichokes, I start by cutting the plants back to about 6 inches above the ground. I then top the plants with the thick layer of straw. Mulched garden artichokes are then covered with a portable cold frame while my mulched polytunnel plants are topped with an old row cover. Uncover artichoke plants in early spring.

Growing artichokes: The best varieties to plant

I’ve grown many varieties of artichokes over the years, but have found the below ones to be the most reliable, particularly those bred for annual production.

  • Imperial Star – This classic short-season artichoke was the first variety I grew successfully in my northern garden. It is bred for annual production and yields a good crop of 3 to 4 inch diameter chokes the first year. Expect several large artichokes as well as a half dozen smaller ones. The plants grow 2 to 3 feet tall. Imperial Star is hardy to zone 7 but easily overwinters in my polytunnel under a thick layer of straw mulch.
  • Tavor – Like Imperial Star, Tavor is also a variety for first year production but it offers a few improvements as well as enhanced vigor. First, the plants are larger, growing up to 4 feet tall and Tavor also produces 1 to 2 more buds per plant which average 4 1/2 inches across.
  • Colorado Star – This exceptionally beautiful plant is the first purple globe artichoke bred for annual production. It was bred by Keith Mayberry, who also created Imperial Star. This variety is very early to mature with the plants growing up to 3 feet tall. They yield 8 to 10 violet-purple buds per plant.
  • Green Globe – This striking variety is grown for its large, rounded buds produced on 5 foot tall plants. It’s the standard globe artichoke in warm regions. I have grown it successfully in my zone 5 garden, but it’s very late to produce and not as productive as the above varieties in my climate.

For more information about growing unique vegetables, check out the following articles:

  • Perennial vegetables: 15 easy to grow choices
  • How to grow ground cherries in a garden
  • Learn how to grow cucamelons
  • Growing edamame in a vegetable garden
  • How to grow quinoa

Are you thinking about growing artichokes in your vegetable garden?