The Garden Community for Garden Lovers

Buckinghamshire, United Kingdom Gb

Several of my pot plants suffered badly in the winter, leaving me with a lot of used plant compost in the pots. I have been told this should always be discarded and that any new planting should have fresh compost. Is this true? If so, how best to dispose of the old compost? Many thanks, Rick



Put it in your compost bin or mix it half and half with fresh compost and use again.

15 Apr, 2013


thanks, Moon grower; I thought it shouldn't be wasted, despite the advice to discard.

15 Apr, 2013


Well first ask yourelf this, why do we feed the plants???
IE the compost you've used is only now for the compost bin or just put it around the shrubs etc in the open garden,

Once compost has been used even if your plants managed to get through the winter it should be changed with good fresh compost full of the needs of your new plants diet,
Even greenhouse compost has tobe changed after a time, "much debate on the time" some say 3 years, some like myself say every year,

the used compost can be a nesting place for all kinds of bugs ect "Ants, just love it.

So i'd say use fresh "Good" not the cheapest stuff but Good compost with all what ever plant your going to grow needs, they dont all want or need the same things.

Before buying compost read the info on the back/side of bag,
it will tell you the N, P,K. Reading this is telling you how much of each chemicle is in that bag,
All you need know is what your chosen plants needs more of ie more pot-ash thenyou need a higher reading of N. and so on.

If you just buy a bag of compost without understanding whats in the bag ref its contents "then you can & will waste your money and 9/10 do the plant no good what so ever.
But if you give the plant just enough of what it needs you'll have some lovely plants or fruits it it's fruit your growing.

15 Apr, 2013


There is no reason not to simply add a balanced feed to the existing compost rather than buying more... this is the artful policy of the GCs to make you spend more than you need to. If we used new potting compost for all our bulbs every year it would cost us a fortune!

15 Apr, 2013


"Which?" conducted tests on bought compost and found that re-used compost gave as good results as the new stuff. We start feeding new compost after a few weeks anyway, so now I just feed the recycled from the start.

15 Apr, 2013


Couldn't afford to use all new compost each year, just remix the top half in the pots with some new and some blood fish and bone.

15 Apr, 2013


Dungy, thanks for your reply, but this year I'm going to try what has been suggested by Lizziebee, Merlinbabydog and Moon_grower - all really helpful, so thanks to you all.

15 Apr, 2013


Hi again,
firstly i made a boo boo on my first reply tonight in as much as i said "n" is for potash, i should have said "k" a silly boo boo but one never the less,

Now all i want to do now is explain why ive said use fresh compost or manure or keep feeding your plants and im going to try to show you why ive said this.

Growing anything veg/fruit/shrubs is very much the same needs as we humans need,

IE we need water/light/food/heat & shade.
plants are the same and like us they need to be in good growing conditions, but not all plants like the same conditions, some do like direct sun and some will die if they get the sun,

But one thing all plants and humans can't live without is food,
Now if you keep growing your crops in the same soil/compost and then after you've taken these crops out of the soil and re-plant more plants you'll take the goodness out of the soil and the soil becomes starved of its goodness, & the plants weak hence they become sick.

Like humans if you keep taking money out of your bank account and you put nothing back! your account becomes unhealthy,
Same thing as the soil, keep taking out without putting anything back!!!!!

Back to the soil/compost.
Once your pot grown plants had used this compost they'd also used the make up of the compost and to say you can re-use this same compĂ´st is wrong, it'll need to be treated as a background to adding all kinds of N.P.K
to bring it back to full strength for what ever your going to grow in it.
Remember the members on here are (as i am) amateur and if you want to find out more ref using spent compost ask the likes of gardeners world www.
Learnwhat compost is all about ie humus and how it all makes compost, "you'll soon understand" why compost needs tobe fresh its a living thing full of bacteria and this makes more compost? Without humus you dont have compost you just have dry material, compost needs to be rotting all the time for the humus to make more compost.

Garden centre's are in my opinion a good place to see just what can be grown and how to do it and they have the complete range of feeds/tools etc,

Im not going to go into them wanting people to spend their money there (I dont know of any business that is'nt wanting customers to spend,) How do they pay their rates/heating bills/buy more stock/pay wages if they dont want customer to come in??

So there you have it,
A few members say use your old compost but add fish/bone etc (you'll have to buy these additives)
or you buy ready made compost with the correct amount of all N.P.K for your choice of plants

Or you can make your own compost,
The choice and results are yours.
Happy gardening.

15 Apr, 2013


I re-use compost every year, only buying new every few years to top up the containers. (If I had found any pests I would replace it.) I add plant food, and water retaining gel for summer bedding in baskets. I have always found the results very little different from new compost. I agree with Moongrower - a lot of the "advice" is a sales pitch. After all, surely the compost itself is only the medium for providing the nutrients? If you top up the nutrients, the compost is as good as new.

15 Apr, 2013


We do check very carefully to make sure there are no nasties in the compost and would never reuse from a diseased plant. With the compost from our bulbs we also use the refreshed compost for a different plant - just in case any babies got missed when we were repotting :-)

16 Apr, 2013

How do I say thanks?

Answer question


Not found an answer?