This study was conducted during two winter successive seasons (2022/2023 and 2023/2024) at El-Gemmeiza experimental farm, Agric. Res., Station (ARC), Gharbya Governorate, Egypt, to study the effect of different potassium sources as soil mineral (MK) or natural feldspar (FS) and foliar spray (spraying with water, potassium fulvate KF (4.5 g/liter) and potassium thiosulfate KTS (1.25 ml/liter) on plant growth, productivity and quality of garlic bulb cv. Balady using clay soil conditions. The interaction between fertilizing garlic plants with 100 % recommended rate (at 96 kg K2O/fed.) and KTS spraying at 1.25 ml/liter and/or fertilizing with 50% MKR (100 kg KS/fed.) +50% FSR (452.83 kg feldspar/fed.) and spraying with KTS gave the best results for increasing vegetative growth and plant dry weight, N, P and K contents and their leaves uptake, productivity and potassium use efficiency, total soluble solids and pungency. There were no significant differences between two treatments. This means that 50% MKR (100 kg KS/fed.) + 50% FSR (452.83 kg feldspar/fed.) and KTS spraying at was the best treatments for enhancing growth, yield and bulb quality of garlic.