How to start winter mulching

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Are you looking for a way to protect your plants while cutting back on weeding and watering?

Read on for top tips on how to start winter mulching, why it’s a good idea and the best type of garden mulch to use. (Psst, spoiler alert – coconut coir makes the best mulch!)

Why your plants need mulch

In winter, we humans can dig out our sweaters and coats to cosy up. But plants don’t have that option. Luckily mulching is an excellent way to keep your plants warm during the colder months. It helps insulate the soil, and therefore plant roots, from frosty air. As well as protecting any soil from being washed away in rainstorms.

A layer of mulch blocks out light. This isn’t a problem for established roots. But it is for any weeds that are trying to grow. Or blown-in seeds that what to set up base. And if weeds do manage to get a foothold, mulch is looser than soil. So it’s far easier to yank them out!

When it’s pouring with rain in the winter, it’s tempting to think that Mother Nature has taken care of the watering for us. But plants need water, even in winter. If you water plants before applying mulch, it keeps more water in and reduces the amount of water evaporating.

Mulching also evens out temperatures. A freakishly warm spell in winter could wake up deciduous plants prematurely. But a mulched plant is less affected by fluctuating air temperatures, and so is less likely to be triggered into spring growth mode.

Biodegradable bonus

But if you use a biodegradable mulch, the benefits don’t stop there. Mulching creates a sort of soil ‘lasagne’. Micro bacteria and organisms can’t resist chomping up this fresh top layer. They then return to the soil below, taking mulch nutrients down to root level. This movement creates tiny channels which encourages drainage and oxygen distribution near roots.

Why humans like mulch

Do you like things to look neat? A layer of mulch across a garden or a collection of pots really ties things together. It also means you’re not having to stare at bare soil through the winter!

Which plants need mulch in winter?

If your patio or garden is going to see temperatures below freezing, then mulching is a good idea.

A shield against extremes

Lots of hardy plants will survive without mulch, but will still appreciate an extra layer to help them fend off frost. Think of mulch as an insurance policy for perennial plants such as salvias, verbena bonariensis and deciduous agapanthus. Also mulch around any lily bulbs that throw out shoots during the winter.

If you grow globe artichokes, mulching around their bases helps protect them.

The dahlia dilemma

Should you dig dahlias up and store their tubers somewhere cool and dry, as recommended by top gardener Monty Don? Or chance leaving them in the ground, as his fellow Gardeners’ World presenter Toby Buckland advises?

If you live in a mild climate with free-draining soil, you might chance leaving them be, with a thick mulch will help protect them against the elements.

Types of mulch

Non-biodegradable mulches

• Old carpet or rugs
• Expanded clay
• Gravel – will stop weeds but not insulate
• Landscape fabric / geotextiles
• Pebbles
• Plastic sheets
• Pumice rock
• Rubber mulch – but there is a fire risk
• Sea shells
• Shingles
• Slate
• Stone chippings

Biodegradable mulches

• Bark chippings – but seasoned not fresh
• Cardboard and newspaper – check ink is biodegradable
• Chopped leaves
• Coir
• Garden compost
• Hay
• Leaf mould
• Manure – but it needs to be well-rotted
• Mushroom compost (already used)
• Pine needles – although they will eventually turn the soil below acidic
• Seaweed – well-rotted and with no salt content
• Straw – but will break down in 6 – 10 weeks
• Seasoned wood chippings (at least one year old) – but be wary of introducing honey fungus. And don’t use fresh chippings as they will leach nitrogen from your soil.
It’s up to you which mulch you use. But given it’s is biodegradable, sustainable and pH neutral, we think coir is a pretty good bet!

How to use winter mulch

Think about what you’re trapping in with your plants before your mulch. Make sure you weed and clear the soil surrounding your plants first. And give them a water before mulching.

Growing winter crops? You’ll need to wait until after you’ve harvested them before you mulch.

Don’t be stingy

The RHS advises biodegradable mulch layers such as coir need to be between 5cm – 7.5cm thick. You can get away with thinner layers in shadier spots. But a thick layer will retain more water, insulate better and prevent sunlight reaching any weeds.

Give them some space

It’s very important to make sure the mulch doesn’t directly touch a plant. You must leave at least 3 – 5cm of space. This should be more for shrub stems: 8 – 12 cm. And 15 – 30cm around tree bases. If mulch touches a plant’s stem or trunk, they can soften. Which puts them at more risk of becoming diseased or rotting.

To leave or not to leave?

Remember to remove your non-biodegradable winter mulch once your plants put out new growth in the spring. And once the threat of a hard frost has passed.

But if you used biodegradable winter mulch, then just relax! Just leave it in place and it will eventually decompose into your soil.

Expanding coir mulch

If you want to reduce weed growth by 90%, why not try out our Coco Chip coir mulch? It’s sustainable, looks great and slugs and snails hate to crawl across it!

When you’re ready to mulch, just put the compressed Coco Coir Chip Peat Free brick in a container. Add water – warm water is faster – and let it sit until the coir absorbs all the water. This usually takes 15 minutes. Then fluff it up and start spreading.

Tips from the ‘Green Gardeners Guild’ online advice library

On the lookout for more tips and hints? Our blogs are packed with advice:

No-Dig gardening for beginners
Mulching as part of winter gardening: a guide
Gardening is good for you

Do you winter mulch?

Do you mulch? We’d love to see the results of your hard work. Please post your pictures and tag @cocoandcoir on Instagram. We’ll credit you for any images we use and you’ll even get £10-worth of loyalty points for any of your stories we use!