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

Free* potato-growing kit

Claim a potato-growing kit, including five Charlotte seed potatoes, five growing sacks, scrubbing gloves and five packets of vegetable seeds (worth over £22) for free - just pay £5.65 for postage.

Order now

Offer

Veg boxes at Abel and Cole

Veg boxes at Abel & Cole

Save 25 per cent on your first four seasonal boxes, and get a free olive oil, sea salt and peppercorns gift box in your 4th delivery.

Use code: GW

Order now

Offer

Free* viburnum and snips

Claim your Viburnum x bodnantense 'Dawn', plus snips and fertiliser (together worth over £23) for free. *Just pay £5.65 for postage.

Order now