By Tintin
Lincolnshire,
United Kingdom 
I grow my tomatoes in planters which fit into growbags, each year I give all my old growbags to the local allotment, now that I am looking after the pennies, would it be a good idea to mix the old growbags with new grow bags and use the compost in my hanging baskets. ps. my garden borders are already mainly old compost.
29 Mar, 2016
Answers
I have been doing it that way for donkeys years Tintin, especially in the bigger pots and troughs, they take a lot of filling up, I used to scatter them onto my beds and borders but found I was getting more of the little spreading weeds so that had to stop, now my mix is old, new, some of my own compost out of the bins and a smidgeon of the slow release fertilizer, the plants don't seem to mind and as you say it can save money, any left over when baskets and pots all planted up goes into the compost bin and it all starts over again......
29 Mar, 2016
I sometimes use some garden soil in the bottom of really big containers because they need such a lot of compost to fill them, and also being heavy it stabilises the pot - we live in a windy place.
29 Mar, 2016
Yes Stera I've done that as well, also find with just compost in the pots it dries out too quickly, no real substance with some composts.......
29 Mar, 2016
Thanks for the advice, I can now afford to go to the pub for longer.
4 Apr, 2016
You can reuse the old compost in baskets as long as it has no pests in it -just add some slow release fertilizer.
29 Mar, 2016