Gardener adding compost to pot

Best compost: which compost is best for which job?

Confused by the types of compost available? We explain which type to use for which job.

With most gardeners using compost to sow seeds, top-dress pots and transplant seedlings, knowing which is the best compost to use can be problematic. Then there’s the peat issue. If the compost isn’t labelled as being peat-free, it won’t be.

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For most plants, and for many seeds and cuttings, a good peat-free multi-purpose compost is suitable, both from an environmental and convenience point of view.

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Multi-purpose composts are soil-less, so they shrink more than loam-based composts when they dry out, and don’t always reabsorb water when wetted. It’s therefore important to keep the compost gently moist at all times and don’t let it dry out.

The nutrients are also more rapidly leached out of soil-less composts than those containing loam. Read the bag for how long the nutrients are expected to last, but you will usually need to start applying a fortnightly liquid feed six weeks after planting plants that are in growth. For trees and shrubs in containers outdoors, use John Innes soil-based compost, which has the weight necessary for stability and the ability to hold onto its nutrients for longer – add grit to prevent it from becoming too hard and ‘claggy’.

If you’re determined to avoid peat, the alternative is to mix a peat-free, multi-purpose compost with good-quality topsoil, to provide stability and moisture retention, and add fertiliser, such as blood, fish and bonemeal. Proprietary compost is tested to make sure it’s suitable for a range of plants. Yours will be a process of trial and error, but you will have the satisfaction of knowing you’re doing your bit for conservation.

For acid-loving plants, such as rhododendrons and camellias, use John Innes ericaceous compost or mix a peat-free ericaceous compost with neutral or acidic topsoil.

If you want to make your own compost from kitchen or garden waste, try our guide to the best compost bin as we talk through all the available options, the benefits of each and share advice on how to get started. For any additional help you may need, we also have a trouble-shooting video on common problems with composting.

Whatever compost you choose, for best results always buy fresh bagged compost rather than an old, stale or waterlogged sackful. Only buy as much as you can use within six to eight weeks, and seal after use to stop bugs and weed seeds getting in, and prevent decomposition. Store it where it won’t get waterlogged.

Find out which is the best compost for which job, below.


Sowing most seeds

Preparing seed tray for sowing seed
Preparing seed tray for sowing seed

Use peat-free, multi-purpose compost.

Buy Peat-Free Multi-Purpose Compost from Amazon


Potting on plug plants

Use peat-free, multi-purpose compost.

Buy Peat-Free Multi-Purpose Compost from Amazon


Rooting cuttings

Rooting cuttings
Rooting cuttings

Use peat-free, multi-purpose compost with half as much vermiculite or perlite added.

Buy Peat-Free Multi-Purpose Compost from Amazon

Buy Vermiculite from Amazon


Plants in pots for less than a year

Potting up a hanging basket
Potting up a hanging basket

These include hanging baskets, summer bedding and veg. Use peat-free, multi-purpose compost.

Buy Peat-Free Multi-Purpose Compost from Amazon


Plants in pots for more than a year

Use equal parts of peat-free, multi-purpose compost and John Innes No.3, or a good topsoil if you want to avoid peat.

Buy Peat-Free Multi-Purpose Compost from Amazon

Buy John Innes No.3 from Amazon


Large plants in large pots kept outdoors for several years

These include shrubs and fruit. Use John Innes No.3 with one quarter its bulk of added grit, or a good topsoil if you want to avoid peat.

Buy John Innes No.3 from Amazon


Acid-loving plants

These include rhododendrons and camellias in large pots. Use John Innes Ericaceous Compost or a peat-free ericaceous compost.

Buy John Innes Ericaceous Compost from Amazon


Cacti and succulents in pots

Use John Innes No.1 with grit added until it feels crunchy, or a bespoke cacti compost.

Buy Westland Cacti & Succulent Compost from B&Q


Orchids

Repotting an orchid
Repotting an orchid

The epiphytic types (those that cling to trees for support) are best potted into chipped bark especially for the purpose.

Buy Orchid Bark Chips from Amazon


Most houseplants

Use peat-free, multi-purpose compost (except for cacti, other succulents and orchids).

Buy Peat-Free Multi-Purpose Compost from Amazon


Adding to planting holes

Use well-rotted garden compost or manure, but many gardeners now recommend simply enriching the soil in the area where you will dig the hole.

Buy Horse Manure Soil Conditioner from B&Q


Mulching beds

Adding a mulch around roses
Adding a mulch around roses

Use well-rotted garden compost or manure, or composted or chipped bark (the latter is longest lasting).

Buy Horse Manure Soil Conditioner from B&Q

Buy Bark Chippings from B&Q


Lawn repair

Use good-quality screened (sieved) topsoil.

Buy Top Soil from B&Q


Filling raised beds

Use screened topsoil with well-rotted garden compost or manure added.

Buy Top Soil from B&Q

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Buy Horse Manure Soil Conditioner from B&Q