Magnesium deficiency

Time to act:

Jun, Jul, Aug, Dec, Jan, Feb, Sep, Oct, Nov

Magnesium is needed to give leaves their green colour, so when there's a deficiency, yellow breaks through between the veins and around the leaf edges instead. Other colours, such as purple, brown or red, might also appear. Older leaves suffer first, and will die if they're not given any treatment. The nutrient can be leached out of light, sandy, acidic soil by high rainfall. Or if there is too much potassium in the soil, the plants absorb that instead of the magnesium.

Symptoms

The absence of magnesium is detected by yellowing between the leaf veins and around the leaf margins. Other colours might break through as the green fades.

Find it on

potatoes, apples, cherries, grape vines, tomatoes, camellias, rhododendrons

Advertisement

Organic

For a long-term solution, apply a yearly mulch of home-made compost. This will conserve moisture, prevent the leaching of nutrients during heavy rainfall, and provide the soil with sufficient quantities of magnesium to keep your plants healthy.

Chemical

Use a magnesium leaf spray, such as Epsom salts, on potatoes for a quick, temporary solution in summer. Apply Epsom salts or calcium-magnesium carbonate to the soil in autumn or winter to remedy the deficiency for next year.

Advertisement

Discover more ideas and inspiration

Related content

Monty Don's favourite fruit

How to plant a bare-root tree or shrub in a pot

Euonymus scale

Rust

Related offers

Offer

Buy one, get one free

Add one cherry 'Stella' to your basket, and you'll have another automatically added for free. You'll also receive a free packet of fertiliser with your order.

Order now

SAVE 20%

Save 20% on fruit trees

Save 20 per cent on this collection of three cordon fruit trees, including cherry, plum and apple. Or, save 15 per cent when you buy a single tree.

Order now

FREE P&P

Subscriber only content

Save £6 on witch hazel

Add winter colour to your garden with vibrant witch hazel 'Jelena'. Buy one plant for £12.99, or save £6 when you buy two for just £19.98, plus free p&p.

Unlock now