Filling raised bed

[rary]

I am making a raised border in the garden I am lifting the soil level up by ten inches I have cut all bushes down to soil level, the bulbs and flower plants are getting covered by old compost from a number of large pots once I have my pots emptied I will level the soil and cover with cardboard which will still leave a depth of about six inches to be filled, will the cardboard down that depth be sufficient to suppress any weeds or plants from growing through?

[Thelma Sanders]

I'd usually say that no weeds would grow through, especially if you are adding more compost on top...............BUT I'm wondering if the bulbs will still make it through to the surface

[geepee]

Weed seeds will only usually germinate in the top 5/6 cm of soil, hence the 'No Dig' method in gardening and 'Direct Drill' system in farming.
Therefore if you believe anything below that level wont grow,you just need to start with weed seed free soil on top of a raised bed and do not disturb below, which is perfectly achievable given you have a compaction free,(Not Walked or trampled on) Loose/free drainage top soil.
The deeper you dig or upturn soil, the more new and fresh viable weed seeds you bring nearer the surface and they start another cycle...!!
Gp

[rary]

Thanks to the two of you I have levelled the material I dumped into the bed and covered it with two inches of cardboard, then topped up one third of the bed with compost

[geepee]

So...how much/what depth of compost have you got above cardboard now .??
Gp

[rary]

So...how much/what depth of compost have you got above cardboard now .??
Gp

There is now five inches of compost on top of the cardboard, I think I will buy some bags of sand to mix through it to help keep it open