Where to source "clean" organic compost for my veg planter?

I have a new brick planter for edible growing and I'm a total novice.
Currently it is completely empty and need advice on the growing medium.
I've bought decent brand compost and topsoil for some flower planters and always seem to find glass, plastic etc in it.
I want to grow some veg and stuff with my 10 year old daughter and I dont fancy filling the planter with contaminants.

I have half a bulk bag of British Sugar hortloam that I sourced form a neighbour which seems fine, I'm told I need to mix in compost and I'll probably need some more top soil too.

I'd appreciate some recommendations on where to source decent stuff.
I'm N Wales based but happy to buy over the internet for delivery from further afield if needs be.
I can probably source some horse manure to compost if that's a better option?
Apologies if this crosses over a bit with the other veg planter thread I started which has been more about what to grow in it
Thanks
Chris

 

I'd be happy to use muck from a dairy farm but I tend to avoid racehorse stables as I think there might be too many 'additives'. If it's just from a local generic horse place it should be ok too.
You'll find plants grow in a wide variety of mediums, I've used spent mushroom compost and coarse sand quite a lot over the years or screened topsoil as a base and add your own goodies, it comes with finding what works well for you.
As a novice, be prepared for a few failures and a lot of reading! Start with the easy stuff and then add to your grow list. Salad crops are good for starters as you can graze on them as you garden!
Others on here will really help with edibles advice

 

Along with the bits of glass and plastic etc, I do wonder what else it may be contaminated with.
I believe the recovered black sludge stuff from sewage treatment finds it way in as an ingredient into manufactured soils too!

 

I had to Google British sugar hortloam.

It sounds like good stuff. If it were me, I'd save that for now, and working on mostly filling your planters with relatively cheapo compost and/or soil and then put the good stuff on top.

If you have access to cheap/free manure, I'd probably just dump that in. I got a trailer load once for free from a riding school. I had to muck the stables out for it but that didn't bother me. It clears the nostrils and if it gets in your shoes it makes you grow.

Bear in mind that fresh stuff is no good for growing most things in, so you'd either need to set it aside for a while or bury it deep under a good thick layer of compost or topsoil. Having said that, the best crop of taties I've ever seen were grown in almost fresh horse manure. Not quite totally fresh, it had been collected in a mound and we needed to get rid of it, so we dug it in and planted taties straight into it. As I say, not totally fresh, but it was still steaming and still good for clearing the nostrils.

 

I was watching a clip the other day called something like "turning horse manure into compost in four weeks" and they just covered it over with plastic and turned it over during the middle of the 4 weeks. Could just be internet nonsense though