Potassium Deficiency
This problem spreads through handling, insects or soil rather than the weather, so there is no live forecast risk — focus on prevention below.
When it strikes
About
Potassium deficiency reduces fruit quality and disease resistance, common on sandy and light soils and in heavy-fruiting crops like tomatoes, potatoes and fruit trees.
Symptoms
Yellowing and browning (scorch) of leaf margins on older leaves while the centre stays green, weak stems, and poor, uneven fruit colour and ripening.
Organic Treatment
Apply wood ash, kelp meal, or a high-potash organic fertiliser, and mulch with compost. Comfrey liquid feed is a good organic potassium source.
Chemical Treatment
Sulfate of potash or a high-potassium soluble feed corrects deficiency during fruiting.
Prevention
Test and balance soil nutrients, feed fruiting crops with potassium, build organic matter, and avoid leaching on sandy soils.