Potash is a term for potassium-rich fertilisers — often derived from mined potassium salts like potassium chloride (KCl) or sulfate (K₂SO₄). In gardening, it’s one of the three primary macronutrients (alongside nitrogen and phosphorus), represented by the “K” in NPK labels.

Warning: Use potash sparingly — too much can harm soil balance or inhibit uptake of other nutrients like calcium or magnesium.

Why it matters in vegetable gardening:

• Strengthens cell walls → improves disease resistance and drought tolerance.
• Boosts fruit & bulb development → critical for onions, tomatoes, potatoes, and root crops.
• Aids nutrient transport → helps plants move sugars and starches to storage organs (like bulbs or fruits).
• Enhances flavor and storage life → especially important for onions and potatoes.

For Red Baron onions, a potash-rich feed during bulb formation helps produce firm, flavourful bulbs with better shelf life.