As a novice Gardener I would like to know if compost I used in pots last year can be mixed with new compost to use this year, or would it be best to put old in compost bin.
Thanks.
As I understand it, barring any infection, the only problem is that last year's plants would have used up much of the nutrients. Garden flower beds is probably best.
The problem with using last year's compost again, is that if there are any of the dreaded vine weevil grubs in it, they are difficult to get rid of. If you spread the compost on the garden, the birds will quickly eat up any nasties.
I use spent compost 50/50 with new stuff every year. Just add some growmore to it. Don't forget, new compost only has enough nutrients for 6 weeks then it's feed time.