Symptoms of vital nutrient loss

Plant health will suffer if important minerals are missing

1 Nitrogen: Needed for healthy leaves, a lack produces stunted plants and yellowing foliage. It is easily washed away by rain, but can be replaced by organic mulch. Fertilisers such as chicken manure pellets also help.

2 Potassium: Helps photosynthesis, water uptake and healthy flowering and cropping. Shortage causes yellow or purple leaf tints and poor flowering etc. Remedy with high-potassium fertilisers such as potash and liquid tomato feed.

3 Phosphorus: This is essential for strong roots and shoots, and its absence causes slow growth and dull yellow foliage. Deficiency is rare, however and can be reversed by feeding with superphosphate or bone meal.

4 Calcium: Helps strong cell formation, but can be blocked by too much magnesium or potassium around roots. Symptoms include yellowing foliage and ‘blossom end rot’ in tomatoes (pictured). Remedy by adding lime to the soil.