Artichokes are regal vegetables with leaves that shine a lush silvery-green in the sun. Typically grown as perennials, artichoke plants can reach three feet in both height and width. Though most people grow them to eat the fruit, when not harvested, an artichoke will bloom a fragrant purple flower that looks very similar to a giant thistle. The plants require moderate upkeep, but they are hardy and reward the gardener's work with a delicious summer harvest.
Artichokes are an outdoor plant, as their root systems need to spread significantly to support their tall stems. When given the proper soil, they do well planted right in the ground or in raised beds. To plant your artichoke, first pick a space in your garden that will leave your plant 4 to 6 feet of space to itself. Artichokes are typically grown in a row, to ensure good sun exposure. If you are growing multiple plants, dig an 8-inch-deep row long enough for all the seedlings. Mix around five inches of compost into the bottom of your row, then you're ready to get planting. Artichokes can be planted in the spring or fall in most climates, although in colder areas they should be planted soon after the last frost, in early spring.
Artichokes require frequent watering to support their root system and stem growth, as well as to keep their flower buds tender. Water your plants one to three times per week depending on outdoor temperatures. For increased water retention, keep a layer of around three inches of mulch at the base. Artichokes need full sun exposure and they grow best in USDA hardiness zones 6 through 9.
Artichokes need to be planted in soil that drains well because they requiring frequent watering, but their roots are susceptible to rot if they are kept in soggy soil. A sandy, fertile soil, that is on the alkaline end of the pH scale is ideal for artichokes. During your plant's growing season, apply a plant-based fertilizer to its base once every couple of weeks.
One of the best qualities of artichokes is that they do not often attract pests, though, occasionally, slugs, snails, aphids or moths can show up. Most pests that find their way up your artichoke plant can simply be sprayed off with a hose. For more persistent ones, try spraying your artichoke with an organic insecticide for edible plants.
Powdery mildew and botrytis blight are the most common diseases to attack artichokes. Mildew shows up as a white powder on foliage and can be fixed by spraying your plant with a mix of 2 teaspoons apple cider vinegar and 4 cups of water. Botrytis blight is a gray mold that grows on the artichoke's leaves. Any affected leaves need to be removed promptly and if the blight continues to spread, apply a fungicide to your artichoke plant — make sure to find one that is safe for use on edible plants. A less-common but incurable disease in artichokes is the curly dwarf virus. This leads to curled leaves, stunted growth, and disfigured blooms and requires the whole plant to be removed, to avoid spreading the disease.
Since artichokes need up to 2 years of growth before they flower, they are usually bought as seedlings from garden stores. To grow artichokes from seed, plant them in a tray full of seed starting soil at least 8 weeks before you plan to move them outdoors. Water lightly, but regularly. Seedlings need to be hardened off to develop buds. This involves placing them outside for about a week in the early or mid-spring to expose them to temperatures between 45 and 50 degrees Fahrenheit. After this, your plants can be brought back indoors until they are transplanted after the last frost.
The most commonly grown artichoke variety is the quick-blooming, heavy-budded Green Globe. Although popular, it requires a warmer climate to flourish as a perennial plant. An especially beautiful variety is the Italian Violetto artichoke. This variety grows abundant side shoots, requires less space since it is shorter than average, and produces purple blooms. The Big Heart artichoke is a thornless variety that copes well with warmer temperatures and grows a large, dense bud.
For artichokes in hardiness zones 8 or higher, the plants can be cut right to their base, just above the soil. Then cover them with multiple inches of mulch, leaves, or straw. For plants in zones 6 or 7, cut the plant, leaving around 12 inches above the soil. Cover the trimmed plants in your choice of mulch, cover the mulch-mound with a plastic bag or a basket, add another layer of mulch and then tuck all that in with a tarp. For all these zones, uncover the plants as soon as the ground has thawed and intense frosts are no longer expected.
For artichokes in hardiness zones 5 or below, you can try the method suggested for zones 6 to 7. However, if you want to be extra careful, you can dig up your plants, place them in pots, and bring them indoors for the winter. When inside, the plants should be kept in a cool, dark place where the temperature remains above freezing. Water your artichokes every few weeks and once the final frost has passed, you can transplant them back outdoors.
An artichoke's center bud will be the first to mature and will be ready to harvest when it reaches around three inches in diameter. Harvest the bud while it is still firm and before it begins to open up. Once the center bud is cut, the plant's shoots will start to produce buds that you can harvest when they are firm and have reached one to three inches in diameter.