Why Are My Artichoke Heads Small and Underdeveloped?

Artichoke heads should be substantial — the terminal head on a well-grown plant can reach 12–15 cm across. Consistently small heads that never develop to a useful size point to a plant that is spreading its resources too widely, not receiving enough nutrition, or simply declining with age in an overcrowded clump that needs renovation. Identifying the cause leads directly to the solution.

Too many stems per plant

Artichoke plants produce multiple shoots from the crown in spring. Left unrestricted, a mature plant may produce eight to twelve stems, each of which produces one terminal head and several small laterals. The plant's energy is distributed so widely across so many heads that none develops fully. In late winter or early spring, select the three strongest, best-placed shoots from each plant and remove the rest. These three shoots will each produce a large terminal head and several usable lateral heads of good size.

Insufficient feeding

Artichokes are heavy feeders that need consistently good nutrition to produce large heads. A plant in depleted soil, or one that has not been fed for several seasons, produces progressively smaller heads each year. Apply a balanced fertiliser in spring, then switch to a high-potassium liquid feed fortnightly from when the heads start forming. A mulch of well-rotted manure or compost applied in autumn or early spring provides a slow-release nutrient base for the season ahead.

Water stress during head development

Like many vegetables, artichoke head size is directly related to water availability during development. Drought stress in June and July — when heads are forming and expanding — permanently limits their final size. Water deeply and consistently through the growing season. Apply a mulch around the plants to buffer soil moisture and reduce the frequency of required irrigation.

Old, overcrowded plant

Artichoke plants decline in productivity after three to five years as the crown becomes woody and congested. An old plant produces many weak shoots and increasingly small heads. Division and replanting with the strongest offsets from the outside of the clump rejuvenates productivity dramatically. This should be done every three to four years regardless of visible decline.