I have a number of patio containers that I like to grow veg in. I have been mixing very low quality garden soil with better quality garden compost and further with some good quality potting compost (about 1/3 each). The first two ingredients are from my garden, and the last from a bag.
I've been reading that I shouldn't use ANYTHING from the garden as it may introduce pests/diseases that won't work well in a confined space. I've been doing not bad so far, everything seems tickety-boo - but have I been just getting lucky?
Can't really afford to spend another £100 on special compost every year to fill up my containers!
Is this a bit of a marketing gimmick or just for people who want to grow prize-winning marrows?