Re-using old compost

Hi, I have a large raised bed which is roughly 9ft X 3ft and 15 inches deep and wondered if there was any way I could revitalise the old compost for next year. I live in a large estate and don't have any garden as such, so no place to dispose of it. Seems a shame just to throw it all away. I would be grateful for any advice on adding suitable fertilisers etc to try and get it back to it's original condition. Thanks

 

Is your raised bed full of compost?

No soil?

 

Yes, completely full of compost

 

Is that a JI composts or the more usual mutipurpose type stuff?

I think you need to be including some top soil, its a better basis to start with.
You can then add organic material, ie manure etc.

Top soil wont disappear in the same way organic material does as it rots down.

 

Hi CarryDuff, and welcome to the forum.

This question comes up several times with reference to old compost in pots, and people disagree - some say chuck it but my view is reuse it. I see compost as a mixture of two seperate things. One is a growing medium which is open and light and holds water but also allows oxygen to get to the roots. And the other is as a fertiliser. Often people think that when the fertiliser component is used up you have to chuck it all out. My view is that you can replace the fertiliser part with liquid feed such as Miraclegrow, or solid feed such as Growmore.

But Pete is right about needing some soil in there. Over a period of time compost, being organic, will start to rot down, it will become finer and the drainage will suffer. For two or even three years your bed will be OK as long as you add some fertiliser, but it will deteriorate with time. When you have trees for several years in large pots they always recommend using a soil based growing medium, rather than just compost. I don't think you have to get rid of it, just add soil or anything else (Perlite or Vermiculite perhaps or maybe even sharp sand) that won't rot down. But soil is probably the best.

 

I have learnt something this year about compost. If I mix my own home grown compost with cheap multi compost........makes for great compost. Just wish I had of learnt this years ago!!

 

Thanks everyone for the sound advice, I will now get some garden soil and a good general purpose feed for next season.

 

I dont know about compost breaking down over time and getting smaller - it actually disappears! Many commercial composts seem to have organic material and soluble fertilisers and nowt else. The fertiliser obviously goes but organic matter over time decomposes and completely disappears cause that is what organic material does - if you knock out a plant that is pot bound you will find a mass of roots and perhaps a bit of grit that was in the compost but all the peat will have disappeared.
John Innes composts contains proper soil - which is a mixture of inorganic material like clay, sand and grit and organic material. The inorganic material is pretty useful cause stuff like the clay particles hold on to nutrients and together with the grit and sand keep the material moist but with air penetration as well. As gardeners we have to constantly replace the organic material in the soil that our plants use up.
Apart from the advice already given can you keep a compost heap if you are not already doing so? Also what about a wormery?