Yes — with a little care. If you’ve got an unopened bag from last year, check it and carry on. If it’s compost that’s already done a season in pots or beds, don’t bin it — you can almost always bring it back to life.

Last year’s unopened (or partly used) bag

If you kept the bag dry, sealed and away from frost, it’ll almost certainly be fine to use again.

Check before use:

• Still light and crumbly — not slimy or matted.
• No sour or stagnant smell.
• No signs of mould or fungus gnats.

If it’s become a bit water-repellent, gently re-wet before use. 👉 See Re-wetting Dried Compost.

Tip: Compost stored in direct sun can lose nitrogen and moisture — if in doubt, mix half-and-half with fresh material.

See also 👉 Shelf Life and Expiry of Compost

Compost that’s already been used once

After a full growing season, most MPCs lose nutrients and fine structure — but that doesn’t mean they’re useless. In practice, a lot of gardeners keep container compost going for years — it just needs a bit of care and the odd top-up.

Typical changes:

• Nutrients mostly spent.
• Particle structure compacted.
• Microbial life dormant (most MPC starts near-sterile).
• Some risk of leftover disease or weeds.

How to reuse it sustainably

• Mix it back through your home compost bin — restores structure and biology naturally.
• Refill established containers or shrubs — mix 5–10% humus or SF60 (biochar-compost) into the top layer.
• Avoid using it for new seed trays or plug plants — too coarse and unpredictable.
• For annual veg planters, refresh and feed mid-season, and keep an eye on disease carry-over.
• As mulch or soil improver, it’s ideal — it still adds carbon and helps retain moisture.

How to refresh used compost

• Break it up and fluff it through — loosen compacted lumps.
• Blend with up to 30–50% fresh MPC, home compost, or topsoil.
• Mix in a cup or two of humus per pot — it wakes the biology back up.
• Feed lightly after planting with a slow-release or organic fertiliser.
• Rotate crops if you can — don’t reuse for the same plant family each year.

Tony’s Steward Insight

Here’s how I approach it after years of testing mixes in my own garden:

“I have shrubs and containers that are seven years old and still thriving in their original compost. Every spring I mix about 10% humus or SF60 (biochar/compost blend) into the top layer. That small dose restores structure, nutrients, and life. A lot of the ‘you can’t reuse compost’ narrative feels like a product-cycle myth — if your mix stays healthy and you manage it biologically, there’s no reason it can’t last.”

When not to reuse

• Smells sour or rotten.
• Has visible mould, fungus gnats, or algae.
• Contained diseased crops.
• Stayed waterlogged through winter.

If unsure, compost it at home or spread it thinly over your borders — it’ll still do good there.

Summary

Check it, loosen it, and reuse it. If it’s tired, mix in a little humus or SF60. If it’s beyond saving, spread it on the borders — it’ll still help your soil.