Establishing grass/ wild flower mix on 4” depth soil over concrete slab?

Sharon.sjbdesigns

Hi!
is there any seed mix that would establish a grass area in 4”/100mm depth of soil over A concrete slab? It’s an old driveway access that will have vehicles Infrequently on tracks in the middle. We would really like to make it a green space that you can still walk on to extend the garden space. The concrete underneath slopes away form the gate. Any ideas please?

K67

In theory it sounds doable but it won't survive, there won't be sufficient drainage in prolonged rain and the grass will just turn brown within days in a dry spell. We have grass verges in our road and this happens around the edges where the kerbs are banked up with concrete. 
I would think any flower would need deeper soil as well.
Are there any cracks in the concrete as you might be able to rake some channels and get in small succulents and some seeds of plants that grow in walls. If it's sunny thyme might survive and can take light foot traffic. 
There is a pansy growing out of the kerbs near us, you couldn't get it to grow if you tried but nature seems to manage!
Oh and welcome.

pansyface

How about you leave enough concrete for car tracks and dig the rest up?

Sharon.sjbdesigns

Thank you for the welcome 😊
that’s really helpful, we could Core drill through sections of the concrete Perhaps to get some soil depth. It’s amazing how the grass seems to grow over pavement where you don’t want it but tricky to when you do. 

JennyJ

If you can break up and remove some of the concrete to make cracks/pockets that you can put a bit of compost in, Sedums (stonecrop) and Sempervivums (houseleeks) would probably do OK even without removing the hardcore from underneath - those common names come from where they like to grow.

Sharon.sjbdesigns

Thanks pansyface - that’s the answer we were hoping to avoid 🤪 It’s about 30m2 that we’d like to reclaim for green space