This study investigates the associations of vigorous-intensity gardening time with cardiometabolic health risk markers. This cross-sectional study (AusDiab) analyzed 2011–2012 data of 3,664 adults (55% women, mean [range], age = 59.3 [34–94] years) in Australia. Multiple linear regression models examined associations of time spent participating in vigorous gardening (0, <150 min/week, ≥150 min/week) with a clustered cardiometabolic risk (CMR) score and its components, for the whole sample and stratified by age and gender. Of participants, 61% did no vigorous gardening, 23% reported <150 min/week, and 16% reported ≥150 min/week. In the whole sample, spending ≥150 min/week in vigorous gardening was associated with lower CMR (lower CMR score, waist circumference, diastolic blood pressure, and triglycerides) compared with no vigorous gardening. Stratified analyses suggested that these associations were almost exclusively observed for older adults and women. These findings suggest the public health potential of vigorous-intensity gardening in reducing CMR.