Thank you Floral. Can you tell me if the squashes and oreganos can sprawl over plastic - or cardboard for that matter? Or do they need to root in soil along their stems? Will oregano never work as a groundcover unless the soil is sterilized?

I wasn't recommending the plastic for growing anything through. Just to stop the weeds getting away from you while you wait for more cardboard. I wouldn't compare squash and oregano. One is a fast growing annual covering a large area and the other is a much slower growing perennial. You could grow squash through the plastic in one season but oregano would need to be dug up and moved when the plastic is taken up.

Bottom line is that, although it's a counsel of perfection, it really is best to totally clear the ground before planting anything.

Mixing mulch is fine -- I do it all the time, use what I have. I avoid wood chips because of the cost but occasionally do pick up a bag if I have a bare area and no more leaves or in pots.

the leaves stay damper.. that is one reason why they break down faster ...

so if repeatedly applied on top of the chips.. it might follow that they chips would break down faster .. which defeats the purpose of putting down the bulkier wood chips.. that would otherwise be there for multiple years ...

i used to mix and match in a different method ... by bed ...if i had a bed the needed the leaves... i might just use leaves for a few years.. then transition to chips ...

ken

If you haven't used either yet in that spot put the leaves down first and then the chips on top.

Plastic has a smothering effect that is detrimental to the soil system.

A temporary covering of black plastic is a recognised organic method of clearing weedy ground. I've used it without any issues on my allotment when cardboard was not available and time was short. The action of soil dwellers on the decomposing weeds produces an easily worked, friable soil when the plastic is removed. The soil does not dry out in my conditions.

"Plastic sheeting: Choose black sheeting to suppress weeds for short periods, or in areas of the garden where appearance doesn’t matter.

• Advantages:
  Cheap
  Easy to cut with a knife or scissors
• Disadvantages:
  Impermeable to water, so the ground can dry out underneath, and rain will puddle on the surface
  Pricking holes in the surface will allow water to penetrate, but can provide an opportunity for weeds to grow" https://www.rhs.org.uk/advice/profile?pid=343