anon-y-mouse wrote:
Usually after my tomatoes have finnished, I empty the growbags on the
the compost heap. Last autumn, this did not get done, and the bags are
still hiding in a corner.

Looking for some soil to fill a trough for some spinach beet seeds, I
wondered if I could safely use the old compost either as a base in the
trough or even to completely fill it, possibly adding some Growmore or
something?

Well, it's probably best to use it as a mulch, or fork it into your beds
(no need to compost it, after all). But if it smells clean and isn't
hosting any fungi, I'd quite likely use it in a container, especially if
I could mix in some garden soil. Spinach beet is tough, and unrelated to
tomatoes. Others may disagree, but I expect it's probably gone rather
acid, so a good dose of lime will help; yes, stir in some growmore, as
there won't be much nourishment in there after the tomatoes and winter
exposure.

--
Mike.