With the exception of Florida (because it’s just too hot), the artichoke can be grown nearly everywhere in the United States. The artichoke is a member of the thistle family, and it’s unusual and attractive flowers make it an intriguing addition to any flower or vegetable garden. The foliage of the artichoke plant can spread up to 8 feet across and 4 feet high. That part that is the culinary delight of cooks across the country is actually the immature flower head of the plant.
While the artichoke is a perennial plant, they are not hardy north of zone 7. Those in the colder climates can grow them as annuals if they start the seeds early enough indoors and can provide them about 90 days of frost-free growing time in the garden. If you are fortunate enough to live in a climate that encourages the plant to thrive, you can expect harvests for about 5 years from the same plant. Artichokes grow best in cool, moist climates, such as what you find on the coastline of California.
Artichokes do fairly well in most any type of soil, but if you want your plant to really grow and produce healthy buds, you’ll need to have fertile, loose, well-drained soil that has a neutral acidity, around 5.6 to 6.6. Sandy or loamy soil is ideal. You’ll want to work the soil to a depth of about 12 inches. A lack of water in the summer and waterlogged soil in the winter are the two main reasons artichokes fail to thrive. Amending your soil with compost to help it retain moisture in the summer months and drain in the winter is important.
What artichokes are, however, are heavy feeders. They require more nutrition as they mature, so you’re going to want to provide them with a good organic fertilizer. Some type of fish emulsion such as Protogrow® is perfect for this application. Some recommendations are to work in one cup of complete organic fertilizer or one shovelful of compost or aged manure into the dirt just before planting. You can also apply 1/2 cup of bone meal or blood meal for each plant.
When to Plant
When to plant depends on the zone you live in, and the best thing to do is call your County Extension agent for advice on the best time to plant artichokes in your area. You’ll want to plant seedlings and they germinate best between 70 and 80 degrees F. Start your seed indoors, about 8 weeks before your last frost date.
How to Plant
Sow your seeds into individual 4 inch pots. As the seedlings develop, you’re going to want to cull stunted plants. Once the seedlings are 8 to 10 inches tall and about 8 to 10 weeks of age, they’re ready to be transplanted to the garden.
Generally artichokes need to go through a cool snap to produce the first flower buds, and that’s usually accomplished by overwintering in warmer climates. If you’re growing them as annuals in colder climates, you can trick the seedlings into reacting as if they’re lived through a winter. Either refrigerate seeds for two weeks before sowing or place your potted seedlings outside for about a week to 10 days when temperatures are around 50 degrees F or a little less.
Plant them in full sun and space your seedlings about three to five feet apart. Remember, these plants are large, so you want to give them plenty of room to grow.
Buds will begin forming in the early summer in most areas (although in ideal conditions you’ll see buds produced throughout the year). The center bud will come in first, and once it has reached a size of about 3 inches in diameter, can be harvested. Harvest while the bud still feels firms and the bracts are tightly folded and still waxy. Cut through the stem about 1 to 2 inches below the bud.
Once the center bud is cut, side shoots will begin producing smaller buds. If you allow the buds to flower, you’ll inhibit the production of more buds.
If you live in zone 8 or higher, once you’ve harvested the last bud in the fall, cut the plants to soil level and cover with 2 to 4 inches of an organic mulch, such as straw. In zones 6 or 7, cut your plants down to about 12 to 18 inches, cover with an organic mulch, and then put some type of large cover over them, such as a basket or crate. Mound another layer of straw or leaves over the basket or crate and cover everything with a waterproof tarp.
In zones 5 or cooler, you can try to the method for zones 6-7 or you can uproot your plants, repot them, and move them to a dark spot that stays above freezing, watering occasionally. You can replant them in the garden once all danger of frost is gone or, if the pot is large enough, keep them as container plants.
Black or green aphids can ruin your crop by spreading viral diseases. Wash them off with a strong stream of water or treat serious infestations with insecticidal soap.
Larvae of artichoke plume moths can tunnel into the stalks and flower buds of artichokes, leaving dark brown trails in the buds and holes in the stalks. When you can spot the small brown caterpillars, spray with a solution of Bt (Bacillus thuringiensis, a naturally occurring bacterial disease of insects) or parasitic nematodes. Once a year, cut the plants down to ground level and destroy the plant material. Do not compost it or mix into the soil as organic matter.
Curly dwarf virus and other viruses can cause stunted or misshapen plants. There is nothing that can be done about this. You’ll have to remove and destroy the plants. Replant in a new area.