The globe artichoke, a member of the thistle family, is a unique vegetable offering a rewarding challenge for the home gardener. While many gardeners rely on planting root divisions or crowns, starting this perennial from seed provides greater variety selection. This process requires careful timing and manipulation of the plant’s environment to ensure a harvestable globe in the first year. Successfully growing artichokes requires understanding their need for warmth followed by a simulated period of winter.
Starting Artichoke Seeds Indoors
Starting artichoke seeds indoors is necessary to produce a crop in the first year, requiring a head start of 8 to 12 weeks before the last expected spring frost. To accommodate the plant’s deep taproot, sow seeds in individual, deep containers, such as 4-inch pots, using a quality seed-starting mix. Plant the seeds about a quarter-inch deep and place them on a heat mat to encourage germination, maintaining a soil temperature between 70°F and 80°F.
Once seedlings develop a few true leaves, they must undergo vernalization, a specialized cold treatment. This manipulation tricks the naturally biennial plant into producing the edible flower bud in its first growing season. Seedlings need exposure to temperatures consistently between 40°F and 50°F for at least 10 days to two weeks. This chilling period signals the plant has passed through winter, prompting it to shift energy toward bud formation instead of just foliage growth.
Preparing the Site and Transplanting
After vernalization, seedlings must be gradually acclimated to outdoor conditions through hardening off. This involves slowly increasing their exposure to direct sunlight and wind over one to two weeks before planting. Transplanting should only occur after all danger of frost has passed and the soil has warmed sufficiently.
Artichokes thrive in full sun (at least six hours daily) and need protection from strong winds. The planting site requires deep, well-draining soil with a rich supply of nutrients, ideally with a pH between 6.5 and 8.0. Before planting, amend the soil generously by working in two to three inches of compost or aged manure to improve fertility and drainage. When setting seedlings, place them at the same depth they were growing in their pots and ensure wide spacing of three to six feet between plants to accommodate their mature size.
Essential Care During the Growing Season
Artichokes are heavy feeders and drinkers, requiring consistent attention throughout the growing season. Because the plant has a shallow root system, it is susceptible to drought, so the soil must be kept evenly moist but never soggy. Deep watering is best, applied when the top inch of soil feels dry, especially during hot summer months and as buds begin to form.
To support the growth of foliage and flower buds, a regular feeding schedule is necessary. Apply a balanced, granular fertilizer (such as 10-10-10) or one high in nitrogen (like 21-0-0) every four to six weeks following transplanting. Applying a thick layer of organic mulch, such as straw or aged leaves, around the base of the plant helps conserve soil moisture and suppresses weeds. Monitor the plants for common pests like aphids, which can be managed with a strong spray of water or horticultural soap. Also watch for fungal issues like gray mold, which are avoided by ensuring good air circulation. In colder climates where the plant is grown as a perennial, cut the plant back to about 10 inches after the first hard frost and cover the crown with a heavy layer of mulch for winter protection.
When and How to Harvest Artichokes
Timing the harvest is important for enjoying the tender, edible portion of the artichoke, which is the immature flower bud. The main terminal bud at the top of the stalk is typically the largest and should be harvested when it feels firm and tightly closed. The ideal size for harvesting is between three and five inches in diameter, taken before the outer scales begin to separate or show any purple color. Purple color indicates the bud is starting to open into a flower.
To harvest, use a sharp knife or shears to cut the stem about one to three inches below the base of the bud, leaving a small handle for preparation. Removing this main bud encourages the plant to produce a secondary harvest of smaller side shoots later in the season. These secondary buds are equally delicious and extend the overall yield. After harvest, store the fresh globes in the refrigerator to maintain quality and prevent them from opening further.