Re-using Old Compost

At this time of year there's often quite a bit of spent compost particularly if you're emptying pots ready for summer planting and from seed propagation. What is less well known is that it’s probably not recommended to put old compost into your council green bin. Old compost may have run out of nutrients, but it is far from useless so here's a few ideas to think about trying. Start by adding some gradually in layers (with grass clippings and vegetable kitchen waste) to your compost bin. The microbial activity along with the mixing action of worms and other creatures living in your compost will reinvigorate the old compost and it won't be long before you can put it to use on your garden. You could reuse it straight away for your containers by mixing the spent (60-70%) with well-rotted manure or new garden compost (30-40%) or you could add straight onto the garden as mulch. Adding directly onto borders won't provide much in the way of nutrients to the plants in its spent form, but it will supress weeds and like all organic matter it will, over time, improve aeration and help to feed the soil organisms, which in turn will help to release nutrients to your plants. Also, it's perfect for adding to any dips or patches in your lawn that need to be reseeded - I use spent seed compost for this particularly. Just don't ever be tempted to use old seed compost for propagation - you need to be sure what you use for this purpose is not harbouring any diseases. Finally, it's worth remembering that any compost you can reuse in your garden will likely save on the environmental costs of manufacture, packaging and transport associated with buying in new bags.