Home made potting compost.

Posy

How difficult is it to make you own seed/young plant/mature plant compost? I make excellent garden compost but I can't achieve temperatures to kill all weed seeds. I have reasonable amounts of leaf compost, too. I use bags and bags of the commercial stuff for my containers but the quality is poorer and poorer and now we have to manage without peat. Could I make my own?

MikeOxgreen

I just use my own made compost, it seems to work well. Any weeds that pop up just get pulled out.
If it's a bit coarse then dry it and put it through a riddle.

Lyn

I’ve got seeds growing on in mine now,  they germinated very quickly, the only weeds I get are those tiny little white things that explode on you when you touch them.

When I’m potting on I sprinkle a little bonemeal in with it.   Don’t do that for pricking out though. 

sheilaffett616_bkDB0q8

There is no single formula for making your own compost because different plants have different nutrient requirements and different quantities of them. The kind of compost you want to be making is called “hot compost” and is made by stacking a pile of green (i.e.: fresh and breakable) waste with brown (i.e.: dry and stable) waste. Then, water the pile as often as possible, adding as much water as you need to keep it hot. Over the course of a few weeks, the pile heats up, killing all the weed seeds and pathogens found in the waste and leaving you with a rich, fertile compost.

Posy

I know about hot compost but I can't achieve it. Last year I had some smashing butternut squash plants and a smattering of tomatoes.  The centre gets hot but the edges don't.  It's truly wonderful compost and I'm proud of it, but sterile it ain't!

Lyn

That’s why you have to put sides to middle,  just like Grandma’s sheets. 

Posy

Well, obviously,  my compost is turned regularly but I still don't get the heat. 

Lyn

You said you get the heat in the  middle,  that’s what heaps do,   just distribute that heat,  so heat the middle, them mix. 

Wilderbeast

If you have a good compost at the end I'd just use that and then worry about weeds after. I make really hot compost but still get some weeds, thing is though we have weed seeds blowing about all the time and you never know it if it's them or what was in the compost. If you have leaf mould then this mixed with some plain compost will make and excellent seed compost. Im pretty sure that most bought compost is no longer truly sterile and with the ban on peat it's more and more likely not to be 

Posy

Thanks, @Wilderbeast. That sounds really sensible.  My 'heap' is on the big side and just contained on three sides by wooden planks so although I turn it regularly, and it makes really high quality compost for mulching, it doesn't achieve the sort of heat you need to kill off seeds and bugs. Indeed, it's packed with worms and a range of creepy crawlies. If I sieve some and mix it with leaf compost, it could be worth a try. Many thanks.