Fertilising: basics

In short: Plants need nutrients, above all nitrogen (N), phosphorus (P) and potassium (K). Fertiliser supplies them, but too much harms plants and the environment.

In more detail: The numbers on the pack (NPK) give the share of main nutrients. Nitrogen promotes leaf growth, phosphorus roots and flowers, potassium resilience.

In detail

• Organic: Compost, horn shavings, manure. Slow-acting, enrich the soil (kompost-anlegen).
• Mineral: Quickly available, precise dosing needed.
• Soil test: A test shows what is really missing before fertilising blanket-style.
• Do not overdo it: Overfertilising leads to weak tissue, nitrate accumulation in vegetables and nutrient input to water.
• Timing: During the growth phase, not in frost or drought.
• Deficiency symptoms: Yellow leaves often indicate nitrogen deficiency, purple-tinged ones phosphorus deficiency (bodenaufbau-und-humus).