Garden design - need help!

[Wonderfulcheapfalafel]

I'm still very much in planning stage as don't have any money to spend at the moment but want to think about what I'm going to do with my new garden. We've only just moved in and unfortunately the previous owners have covered the entire garden with plastic grass, it's awful and I want rid!

I have lifted some of it to see what's under there and it seems like a layer of sand, weed suppressing membrane and then some highly compacted rubble (about 5cm deep). So depressing . It will be a massive task, and probably require a skip to dig all the rubble out. As I am not too bothered about having a lawn I wondered if I could just removed the plastic, and then build raised flowerbeds directly on top of the rubble, I could make some pathways with gravel and have a couple of seating areas.
Would this work? How deep do you think raised beds would need to be? Would be mainly growing perennials and perhaps a few smaller shrubs. Can I just do it directly onto the rubbly stuff or is there a risk it won't be good enough drainage?in every other respect the house and garden are perfect and I love a garden project, but I'm just so sad they dug up their lovely big lawn ....
any advice or inspiration would be amazing. I'll try to attach a photo if I can, if that would help

To be honest, I think that if you build raised beds directly onto the rubble, you will have a problem with them drying out altogether in prolonged dry periods.

It’s unlikely they would have dug up a perfectly good lawn and replaced with plastic grass. More likely the lawn wouldn’t grow well for some reason - shade, poor drainage etc. I would live in the house for a little while first and see what the conditions are like in the garden, where gets sun etc before you make any plans.

I agree with the pp that plants will struggle on top of the rubble. It’s probably very good drainage wise (you will find out soon enough when it eventually rains!!) it’s more the opposite problem ie it won’t hold enough water and nutrients compared with soil. You may be ok with plants that do well in dry/rocky places eg succulents, creeping thyme, alpines.

Do you have DC? Your proposed garden sounds lovely but not very child suited.

Do you think they covered it because nothing would grow on the rubble?

First thing to do is to uncover an area and dig down a good 18 inches. Is there any soil at all?

If there is the you need to work out what type of soil it is and whether the work involved in bringing in top soil to cover if for lawn, and compost for growing is even in your budget.

Or are you going to just have to grow a gravel garden (see Beth Chatto) as without soil you are pretty limited.

Laying rubble for drainage is standard for plastic grass.

and yes it’s hugely possible they dug up a completely fine lawn to do this and used the excuse of don’t have time to cut the grass, have a dog,kids like to play or some other nonsense.

Agree with pp re digging. I used to install artificial grass and recommensation is 10mm sand blinding with 60-100mm hardcore underneath so digging out wouldn't be massive. You have a few options.

In my experience plently of people replace perfectly good lawn with artificial turf. I hate it myself but some find it more practical especially for pets.

A quick and easy thing to do it to get timber off cuts. Dig a small trench about 30-50cm deep and put in the off cuts upright packing in the soil around them to hold them. I put them in staggered for effect. You can use this as a retaining wall for a raised planter. If you want a deep planter you can concrete it in which is easier then you think just buy the premixed dry stuff and add water in a bucket.

Happy to discuss more. I work in landscaping

This reminds me of purpose built sensory/accessible gardens, which can be very successful. I'm sure it will be possible.

I have limited experience with raised beds but from what little I have, I'd have them tall enough to allow for the filling not to come to the top. Otherwise you're always getting soil spilling over on to your lovely clean paths. As for how deep they have to be in total, not many things need more than 20cm root depth and a lot can make do with less. If the bed overall is taller than this you can fill the bottom with something inert and top it up with growing medium (maybe with a permeable barrier in place).

Also think about how your back will feel working at different heights, and how far you can reach, as you won't want to be clambering on to a high bed to get to the back of it.

My veggie beds are made from railway sleepers. One bed is double height and one is single. Single is easier to work on but makes more mess. Double is a good height for sitting on with a cup of tea. You can get sleepers reclaimed or new, reclaimed look more rustic but are messier. New are easier to handle and weather down anyway within a short time.

It sounds like a lovely project, send pictures!

Sleepers can be expensive. We used scaffolding boards which are similar as the timber wall was vertical. If you are worried about drainage you could use a planting medium that is absorbant, lots of bio material or simply put a material layer over the hardcore which will retain water. Ive used sacking cloth but there is probably something better on the market.

Alternatively just plant dry tolerant plants. I have a lot of salvias e.g. hot lips which are very good value easy to maintain, Hardy and drought tolerant.

Thanks so much for all your helpful replies! Sadly I think the artifical lawn was installed as a convenienece measure although the previous owner had a disability so perhaps the maintainance of a real lawn was too much for them. they're lovely people so I'm trying to reserve judgment!
The garden is SE facing and quite a sun trap for most of the day.
@minipie DS is 13 and past the running around on the lawn stage so he won't be bothered. We're going to have a table tennis table and basketball hoop which will hopefully keep him entertained.
@Luckydog7 do you think that digging up the rubbly stuff is achievable then? It seems like such a big job (garden is slightly irregular shape but probably about 30-40m2 of plastic lawn covering) I can't quite picture what you mean about the timber off cuts, can you link to a picture at all? Would really appreciate some indight from a landscaper as I am a complete novice.
@MontyDonsBlueScarf thanks for your words of encouragement! and yes i definitely need to take into account the size of any raised areas. We're lucky enough to have another section of garden which will be used as a vegetable garden so will also be building some raised veg beds there but was just planning on having lower ones. The ones in the bit of garden we'll be using for sitting/entertaining I'd quite like to have edges you can sit on, if you see what I mean?

Ideally I'd just like to be able to dig beds whatever shape I like but if the rubbly ground is going to make that too difficult then raised flowerbeds was my alternative thought!

Picture for you. This is what i have, its surprisingly easy to do just make sure you trench at an appropriate depth for the height of the planter. You want 30%-50% of the total length underground.

I mention the depth of the hardcore so you can decide if it is worth getting rid of it. It is possible it was installed differently or onto an existing layer of hardcore that is deeper then standard. you can only know by digging a sample hole to see how deep it goes then calculating how much there would be to remove and if that is possible/worth it. a standard method of installation would also include a concrete 'ring beam' around all the edges which the grass is glued onto.

If you do remove it you might need to replace with extra material/top soil so need to factor in spoil removal and buying in new top soil. The logistics, i.e. moving tonnes of material is often more expensive then buying the stuff so keep that in mind.

This is just to inform you as much as possible as i don't know what time/budget/trouble you want to expend. or how big of a project you want.

If i were you i would explore how deep the hard core is in a couple of places and then decide. You could always dig up a small area and see how much work that involves before committing to the whole garden.

It might be easier to remove it all now as it is exposed and there are no plants in the way but if you want this depends on your long term plans for the garden.

Your original idea of the raised planters will work either way.

Aye. I know. Which is why I suggested digging down to see if there is any soil. Did you not read that bit?

Oh sorry, just saw your area size. Meant to add. If the rubble area is 40sqm, even if it is only 100mm deep then that is about 6-8 tonnes of rubble. hmm yes quite a lot. one large skip load.

Thanks @Luckydog7 for the pic, this could be do-able for sure. ... That's what I feared re the tonnes of rubble... I think I will follow your advice and just do one small bit to begin with and see how I get on. At some point I'll draw a plan of the garden as would love to get others ideas of how to lay things out. It's nice having a blank canvas I just wish it wasn't a plastic one🙁

Great op would love to see your design!

My last garden was almost entirely on raised beds, because the garden was sat on pretty much solid rock with hardly any soil.

The most successful beds were 40-50 cm deep. That takes lots of soil to fill, but gives you enough depth to plant most things. If they are big enough, the fact that they are well draining due to be sitting on rubble should not be that much of an issue, but it would probably be a good idea to plant relatively drought resistant plants. I was in the med area, so all my plants were of this type anyway. Roses did well enough, though.

One tip is to overfill them with soil slightly. It settles down enormously over time, and if you fill it just to the level it is likely that your plants will end up sunken relative to the beds.