Nutrient

Visible Symptoms

Possible Causes & Remedial Action

Calcium

Cupping and burning of leaf tips with blackening of young leaves. ‘Blossom end rot’ in tomatoes, ‘bitter pit’ in apples and pears

Calcium deficiency can be caused by an irregular watering regime, especially in tomatoes, or a period of drought. Calcium ions are highly soluble and may be leached out of soils by high rainfall, leaving soils with a low pH (highly acid). A quicker acting remedy may be effected by the addition of calcium nitrate, and a longer term, more sustainable, solution is to lime the soil every third or fourth year.

Magnesium

A yellowing between the veins in older leaves (interveinal chlorosis) giving a marbled appearance.

There is usually sufficient magnesium in most soils, but non-soil composts or a high potassium feeding regime, such as that for tomatoes can lead to a deficiency. If either potassium or magnesium presence is excessively higher than the other, it can hinder the uptake of the lesser and cause deficiency. To redress the balance a solution of magnesium sulphate (Epsom salt) should be watered into the soil or compost.

Iron

Yellowing between the veins on older leaves and the production of pale yellow or nearly white young leaves

Iron becomes less soluble at higher pH (more alkaline) and more difficult for plant uptake (lime-induced chlorosis). A solution of iron sulphate or a proprietary sequestered iron compound will usually restore the balance. More likely to affect very acid loving (ericaceous) plants growing in soil with too high a pH.

Manganese

Yellowing between veins of young leaves, but may quickly spread to other older leaves

Usually occurs quite rarely. A solution of manganese sulphate or the addition of trace elements should remove the problem

Zinc

This is usually quite specific for certain plant species and difficult to detect without detailed analysis

Very rarely occurs. Add trace elements

Copper

Very dependent on plant species. New leaves become greyish-green, yellow and occasionally white

Very rare. Water with v. weak copper sulphate solution or add trace elements

Boron

Brittle tissues which crack easily. Death of growing point and production of side shoots

Can occur in brassicas, especially if affected by club root. Can also occur in beet causing ‘browning’ of the root colour. Add solution of borax or trace elements. More prevalent in sandy soils.

Molybdenum

Rarely occurs but can affect cauliflowers grown in sandy soil. New leaves become progressively twisted and reduced until only the midrib remains (condition known as ‘whiptail’)

Element leached out of free-draining sandy soil. Solution of molybdenum sulphate or addition of trace elements.

Chlorine

Wilting

Osmotic balance upset, very rare. Check first that plant not suffering from drought or excessive waterlogging, then check if the roots are being attacked by pest or disease. Add weak solution of potassium chloride if none of above.