Compost differences

I have submitted a query to Homebase regarding the first lot of compost that I bought from them. I'm willing to give the other bags a go, but I won't do it at my cost. I've lost probably £15 of seeds that haven't managed to germinate in that compost, and over a month of sowing/growing time.
Even the stuff I've put in that compost that were established plants are showing really worrying signs of distress, so I've repotted/replanted everything into the newer compost that I bought.

Compost should be fit for purpose whatever it's made from, or what brand or make. What I got in the first couple of bags that I've used isn't good for anything but the lawn possibly.

Gardener's World Recommended Peat Free composts include one from Homebase. https://www.gardenersworld.com/product-g...-composts/

Gardener's World Recommended Peat Free composts include one from Homebase. https://www.gardenersworld.com/product-g...-composts/

That's not what I ordered, sadly... It was this:

SupaGrow

I know it isn't intended for seeds now, but I didn't realise that at the time. When it says organic COMPOST, you expect plants and cuttings to thrive in it. My plants and cuttings are not happy at all in it  My lesson learnt is definitely to read the labels more closely, and take more notice of the brands and reviews.

There's a Youtuber I watch who planted in to raised beds filled with 60% green waste compost, and nothing grew well. He had the soil analysed and it was really, really high in nutrients. Bearing in mind 30% of the mix was peat, which is very low in nutrients, the levels of some nutrients like potassium and phosphorous were up to 10x higher than is considered healthy. So I guess if this Supagrow stuff is 100% green waste, it's just too strong for young plants.

That's always been my worry about green waste, TMTT.
Joe Bloggs may not have a compost heap, or doesn't want to put treated grass cuttings in there so puts them in the garden waste bin. Household waste bins, here anyway, are too small for filling with grass cuttings - in fact I think we've been told they're not to be used for garden waste. How else would Joe BLoggs get rid of them??

They also say on the label to leave the first clippings on the lawn, which is actually very good for recycling nutrients back in to the soil but if you walk on the grass you pick clippings up on your feet and spread them everywhere. They then say to compost subsequent clippings 'well' for at least 9 months and then use as a mulch. Most people don't compost at all, let alone well, so...

Reading the quality requirements for green waste compost, if they conform to BSI Pas 100 standards they have to test for heavy metals and do tomato/field bean growing tests where 80% of the seed has to germinate/subsequent plants have no abnormalities/grow to 80% of the weight of a peat based control. So you assume that any weed killer contamination would get picked up somewhere along the way, but obviously something is going wrong in the quality control process.

I am now using sterilsed soil and burn sand for my seeds and when transplanting I add a bit of B,F,B, I thought that it wasn't working out too well as I was only getting one or two seedlings, things have improved since I have caught 4 mice, but still losing some transplants so trap left in place, hopefully things will improve

I've been mostly using B&Q multi-purpose compost (had a tiny bit of leftover stuff from another brand) for all my sowings and potting on. It's seemed okay for most things but I'm having terrible luck with my brassicas. They are either not really germinating at all (though that may have just been that the kohlrabi seed I have is no good), or germinating beautifully and then suddenly dying a few weeks later. Very frustrating. I have lost all my cauliflowers this way (they had been looking great) and now most of my cabbages are going the same way. They are indoors, so it's not that they have been frosted.