Expert shares decking staining warning and tips to avoid permanent marks

Tree debris and leaves can leave stains when left unswept, explains landscape gardener Karl Harrison

wooden decking in a backyard
(Image credit: Getty images / John Keeble)

A landscape designer has shared a decking staining warning. Karl Harrison explains that if debris and leaves are left on your deck for too long, they can cause lasting damage. 

When it comes to how to clean decking to keep it looking as good as new for many years to come, regular sweeping is really important. Because tannins from dead leaves can cause stains, cautions Karl, from decking retailer Trex.

wooden decking in a backyard

(Image credit: Getty images / John Keeble)

Decking staining warning

‘Keep your deck clear of fallen leaves and tree debris that can decompose and leave tannin stains on your deck,’ Karl tells us. Tannins are bitter compounds found in wood, leaves, seeds, stems, and grape skins, and are what creates a drying sensation in your mouth when drinking red wine. 

Keep on top of sweeping your decking not only to keep your outdoor living space tidy but to avoid unsightly marks from this substance. Trimming back overhanging trees and branches will also help by reducing the amount of debris falling onto your deck.

We also quizzed Karl for his top tips on maintaining your decking aside from regular sweeping, now that spring has arrived and we're heading outside more. Banish grime that’s been building over winter by using warm soapy water and keep composite decking in good condition throughout the year.

wooden decking in a backyard

(Image credit: Getty images / John Keeble)

‘For best results use a mild detergent on a wet deck, leave on for a few minutes for it to work, then jetwash off.’ Karl says that a small low-pressure machine is more than adequate for the job. 

If you’re looking for the best pressure washer for cleaning up decking, patio paving and garden furniture, head to our round-up. A soft-bristled brush will do the trick on any stubborn marks or dirt, he says. 

But as with any household task, it's all about consistency. ‘A routinely three to six months washing will clear away mud, dirt, and soil that can accumulate over time,’ he adds. ‘This prevents the accumulation of moss and keeps your deck looking clean.'

wooden decking in a backyard

(Image credit: Getty images / John Keeble)

If you're on a tight budget or want to use more eco-friendly cleaning products in your outdoor space, Harry Patte-Dobbs from Garden Buildings Direct has a natural deck cleaning tip. Harry suggests the 'trusty combination of a hose, broom, and baking soda' to scrub your deck up.

Alternatively, look into how to paint decking to give the space a whole new look.

Millie Hurst
Millie Hurst

Millie joined Gardeningetc in early 2021. She loves creating a vibrant display of containers in her small urban garden and is always picking up new plants at the local garden center. She's never without some fresh flowers at home and her favorite houseplant is her variegated pothos that's currently climbing its way over her bookshelves.