The cardoon plant (Cynara cardunculus L.) is one of the most promising plants suitable for cultivation in the reclaimed desert lands in the Kingdom of Saudi Arabia (KSA). Here we report for the first time the cultivation of cardoon in the KSA, in particular at Alkharj Governorate. A field experiment was carried out during two successive seasons to study the effect of magnetic fields (MF) on cardoon growth and its oleic acid content. A 75 mT (millitesla) MF was used as follows: MF0 (control) not exposed to the magnetic field, three different MF exposure durations studied as MF1 (T1): 15 min, MF2 (T2): 30 min, or MF3 (T3): 45 min, considered for both nonwetted/ dry (D) and wetted seeds (W). It was found that the MF had significant effects on most of agronomic parameters studied. Plant height (cm), number of leaves, number of offshoots, width and length of the fifth leaf (cm), and length of the longest leaf (cm) were all influenced by an increase in MF exposure time, with significant differences between dry and wet seeds. Of the various MF exposure durations, MF2D and MF3W exhibited the best growth attributes for dry and soaked seeds, respectively. Additionally, the oleic acid (C18:1) content in produced seeds was significantly influenced by 15 min of exposure to the MF, in the case of both dry and soaked seeds. These findings may open new prospects for the industrial use of MF and the cardoon plant, and offer the potential to increase growers’ incomes.