Evaluating the Effect of Cultivar and Planting Dates on Garlic Growth and Yield in North Dakota

Planting date and cultivar selection are critical factors influencing garlic growth and yield. This study was conducted at two locations to evaluate the effects of three planting dates (Sept 28, Oct 12, Oct 25) and six cultivars (‘German White’ (GW), ‘Music’ (Mus), ‘Georgia Fire‘ (GF), ‘Korean Mountain’ (KM), ‘Georgia Crystal’ (GC), and ‘German Extra Hardy’ (GEH)) on garlic growth and yield. Data were collected on leaf number (LN), plant height (PH), scape length (SL), scape weight (SW), bulb weight (BW), bulb diameter (BD), plant fresh weight (PFW), plant dry weight (PDW), and clove number (CN). Results showed that the interaction between cultivar and planting date significantly influenced PH, LN, PFW, PDW, SL, and BD but not SW, CN, or BW. The cultivar ‘GW’ planted on Oct 12 had the most leaves, whereas ‘GEH’ planted on Oct 25 had the fewest leaves. The tallest plants were ‘GW’ planted Oct 12 and ‘Mus’ planted Sept 28, while ‘GEH’ had the shortest plants when planted Oct 25. The greatest PFW was ‘GW’ planted on Sept. 28, while ‘GEH’ planted on Oct 25 had the lowest PFW, approximately 87% lower than the highest. Similarly, the highest PDW was ‘GW’ planted Sept 28, whereas ‘GEH’ planted on Oct 25 had the lowest PDW, approximately 84% less than ‘GW’ planted Sept 28. The longest scapes were ‘Mus’ planted Sept 28 and ‘GW’ planted Oct 12. The BD for ‘GW’ planted Sept 28 were 99% larger compared to ‘GEH’ planted Oct 25, which had the smallest BD. The cultivar and location interaction also significantly affected LN, PH, PFW, PDW, SW, SL, but not BD, BW or CN. The highest leaf number were ‘GW’ and ‘Mus’ planted at the Horticulture Research Farm (HRF), while the tallest plants, longest scapes, and heaviest scapes were ‘GW’ planted at the HRF. The greatest PFW were ‘GW’ planted at the HRF, while ‘KM’ at the HRF had the lowest PFW, which was 71% lower. Similarly, ‘GW’ planted at the HRF had the greatest PDW, whereas ‘KM’ planted at the HRF had the lowest, approximately 64% lower PDW. The interaction between location and planting date significantly influenced PH, LN, PDW, SL, SW, BD and BW but not PFW or CN. The highest PDW, SW, and SL were garlic planted Sept 28 at the HRF, while the lowest values were garlic planted Oct 25 at the Agriculture Experiment Station (AES) plot in Fargo. The most leaves produced, and tallest plants were when garlic were planted Sept 28 at the HRF, while the fewest leaves and shortest plants were garlic planted Oct 25 at the HRF. The greatest BD and BW was when garlic were planted Sept 28 at the HRF, which was 263% higher than the lowest BW and 57% larger than the smallest BD of garlic planted Oct 25 at the HRF. The correlation analysis revealed strong positive relationships between BW and PFW, PDW, BD, and SW, indicating that these traits were strong selection criteria for improving garlic bulb yield while LN, CN, and SL exhibited moderate to low correlations with BW. Results indicate that ‘GW’ was the most adaptable cultivar under North Dakota conditions and that early fall planting, particularly around Sept 28, significantly enhanced garlic yield, making it a recommended practice for optimizing production.