Questions about mulching (to kill weeds)

Hi again,

I’ve spent the last two weeks digging up everything and anything in my garden (which was mostly giant weeds including bramble that I used SBK Brushwood on beforehand). Some of the photos posted are of the garden at it's worst. My back is knackered!

In the perimeter beds I’ll be laying down cardboard and mulch layers for 9-12months to kill all the weeds and restore the soil for planting next year. I'm hoping to plant rose cuttings from the front garden in at least one of the raised perimeter beds.

I wanted to check a few things about creating the mulch layer:

• I have lots of unmarked/non-inked cardboard but it’s quite a bit thinner compared to regular cardboard boxes. Is there an ideal thickness for cardboard used in mulching? Should I double up?

• I have a massive bin bag of three-week old garden waste of mostly weeds and lawn clippings ,which has started decomposing into black mush. (Eek!) Can I spread this out UNDER the cardboard?

• Some of the weeds are bramble leaves onto which I sprayed SBK Brushwood weedkiller – I’ve read that this breaks down in soil relatively quickly. Considering the mulch will be laid down for a year, should I avoid putting this under the cardboard layer?

• There's a bag of all-purpose compost that split open (about three years ago) exposing most of the contents. I’ve read on forums that you should throw split bags of fertiliser is it the same for compost? I’d like to put this on top of the cardboard layer.

• I found tiny unopened vials of baby bio that’s probably somewhere between 5-10 years old. If I can’t use it in the mulch– how do I dispose of it during lockdown?

• Under the cardboard, is it okay to leave lots of thick dead bramble pieces along with other twigs, leaves. At the moment it’s almost like a carpet of twigs. How much wood is too much? See photos please.

• I know black ground fabric or plastic is the best option to top off mulch layers but I have a crazy amount of white fabric that I would like to get rid of. I would make a triple layer of this on top of a cardboard-newspaper-compost mulch layer (weighed down by bricks). I'm not sure what the fabric is made of so could it potentially be something bad for the soil?

• Will mulching like this help with heavily cemented/compacted soil? In one isolated but large area the soil is full of clay (very reddy-brown and mushy in texture - see photos). Would it be better to dig this up?

Any help would be much appreciated!

Thanks,
Shy

 

It's worth mentioning that while digging up all those weeds, there was plenty of worms and bugs in the soil. (Less in the clay areas.)

Does this mean I don't have to worry about organic matter in the layers?