Instead of plucking a globe artichoke off your supermarket, consider picking it from your garden.
Most of the United States, production of globe artichokes occurs in a small area of northern California where the artichokes grow as very large perennials, but you can grow them in Colorado.
The key to growing artichokes here is to consider them as annuals started as transplants. (The plants sometimes can overwinter, if they are heavily mulched, but they are fairly tender and will die out if root temperatures drop below 20 degrees).
Start seed indoors early, preferably before March 1. At room temperature, the seeds will germinate on moistened towels in about a week; they require no special handling. Transfer them to pots that are a minimum 3-inch diameter, and keep the soil evenly moist. Fertilized and cared for, they grow quite rapidly and will produce four to six pairs of leaves by the time they are transplanted outdoors in mid-May.
Varieties of globe artichokes are limited. The longtime standard is Green Globe Improved, which always has done well, provided the plants are started early enough. More recently, some companies have offered Imperial Star, which is reported to be better adapted for annual culture, producing fewer "blank" plants that fail to produce buds in the first year. Searching through garden catalogs, you also might find Violetta, a purple and very spiny variety of artichoke with good flavor but marginal yields.
Site selection is important. Globe artichokes grow quite large and don't tolerate overcrowding, so give each plant at least a 30-inch by 30-inch space. They need full sun and a reasonable well-drained soil. Transplanting can be a bit of a shock, and, as they become established, the plants grow little for the first few weeks. By late June, however, the plants will take off and soon fill the area provided for them. Globe artichokes have moderate watering and fertilizer requirements, similar to that of most garden vegetables.
The edible part of the globe artichoke is the newly produced flower bud. Production of these usually will begin in early July, although there is a lot of variation among individual plants. The buds should be harvested as soon as the shoots have fully extended. Delaying harvest causes buds to mature and transform more of the desired "heart" into a spine "choke".
You can expect two or three store-sized artichokes per plant, which after cutting will produce new buds that are progressively smaller. You will not find the smaller buds in supermarkets, but personal experience indicates they are more tender and flavorful than the larger artichokes.
Artichoke in bloom
Photographs courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010