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

Rust

How to make a Christmas table decoration

Related offers

Offer

Save 15% on apple trees

Save 15 per cent on some of Monty's favourite apple varieties, including 'Herefordshire Russet', as featured in the October issue of BBC Gardeners' World Magazine.

Order now

Offer

Apple 'Egremont Russet' 3 for 2

Buy three apple 'Egremont Russet' trees from DT Brown for the price of two, plus enter our offer code at checkout to save £2 on postage.

Use code: GWD17TREE

Order now

Offer

Subscriber only content

20 free* strawberry plants

Claim your collection of 20 strawberry bare-root plants (worth over £21) for free - *just pay £5.95 for postage. Please add the strawberry collection to your basket and enter our offer code to claim your discount.

Unlock now