Substrate soil garden - help!

[Justheretotalkplants]

Here to beg for help from experienced gardeners please. 🙏🏼

The back of our garden is sloped, and has a significant section which is just substrate soil. We ran out of topsoil before we could cover the slope, or the flat part behind it. Bringing in more topsoil isn't an option for us.

We've sprinkled wildflower seed mix on the substrate slope, though aren't too hopeful it'll grow.

For the top part, our eventual plan is apple trees planted in pockets of topsoil, but we can't afford to do this for a while. In the meantime, is there any lawn seed that would tolerate well drained substrate soil in your experiences?

You can turn subsoil into topsoil by adding organic matter, digging it in and waiting for worms to work their magic. Try composted bark, spent compost from pots, grass clippings etc. Spread it over and fork it in.

You could try green manure for very poor soil. Buy enough seed to cover the area and hope for the best.

@Yamadori thank you! It's a really big area unfortunately, I don't think we'd be able to source the compost matter cheap enough or have the time to do it. (Small kids, full-time jobs & a dream of being a hobby gardener.)

@ConBatulations thank you too! I like the idea of green manure - I looked it up and Clover seems like a beautiful option. Torn between crimson clover for a pop of colour, or micro white clover which would look neater. I think I can get enough seed to do the area for under £90. 🤞🏼

A mixture may be better than one or the other. If you don't already have one, start home composting. Also, check your council as some have free soil improver made from the green waste they collect.

How has the subsoil got to the surface? Is it a new build ( and the builders sold off the top soil?) Or have you had some landscaping done? It may not be subsoil but topsoil with little organic matter. You need to improve the whole area. If you plant into pockets of topsoil the roots will never leave the confines of the underground 'pot' you have created. Water will tend to drain into it too.

YY, pockets of topsoil isn't a good idea.

I like your thought of wildflowers - especially if you get a mix that likes actively poor soils, as lots of them do. You could also be brutal and cut them in as green manure. If it's a field-sized area (acres) then definitely worth it - I know of someone who initially sowed green manure across 5.75 of her 6 acre garden and reduced it over 15 years! By the time she got to the last bit it was definitely rich soil.

But, are you sure you can't afford enriching the soil? Forgive me if I am being unhelpful, but I think private gardeners often don't know what landscapers can do. You don't want to enrich a large area with 'compost' as such. You want to approach a good nursery (ideally one that supplies trade) or large landscaper, and ask about their prices for cubic metres of mulch. Where I am - and I am Yorkshire, it it is eccentric - my local nursery sent me off with a flatbed truck and two cubes of manure/topsoil mix. I forget what it cost then but the price now would be about £80, which is vastly cheaper than most people imagine when they think about 50ltr bags of compost being 6 or 8 quid. Again, although I didn't approach a landscaper to spread it, I could have done, and it needn't cost as much as you think - or you could, dare I suggest, see if any local teenagers would give it ago. After all it is not skilled work.

(NB: I know two cubes doesn't go far if you have acres; it's just two cube is as much weight as you can legally transport on a standard flatbed truck. But you get the idea.)

How has the subsoil got to the surface?

That's what I'm wondering too.

Thank you everyone! We're in a new build, on a sloped site. When we dug out the foundations we had a huge hill of soil left over. We levelled out the front of the house for lawns, and ended up making a kind of two tier garden. The digger driver advised there was a lot more substrate soil than topsoil, and didn't have enough to cover the back slope.

I'm really (pleasantly) surprised about mulch being that inexpensive. I assumed it'd be costly given the price of compost for a little bag.

Also slightly devastated the pockets of topsoil won't work. We were saving for the apple trees for next year, and I'm incredibly glad to learn that before we forked the money over.

Wild flowers love poor soil. What is the aspect? If it’s south facing and the soil isn’t too compacted (if it is you’ll need to rake it) then you’ve a good chance of getting a nice meadow going. The hardest part of getting a meadow going normally is getting rid of the grass, and reducing the nutrient level of the soil, so you’re already ahead of the game.

How steep is the slope? This is quite important.

You could also see if you can get free soil improver from anywhere - my MIL recommended seaweed to me which I’m going to try when the plants that survived my clay subsoil have died back for winter. I’m planning to go down to the beach and gather a bin bag or two. Strew it on. They used to put it on the veg patch every winter. Or do you know anyone with horses/chickens?

@VenusClapTrap 🤞🏼🤞🏼 for the flowers, though I planted them about 3 weeks ago now and it doesn't look like much has happened. I wasn't expecting them to flower until next year, but I did expect to see more signs of germination. Only a few are sprouting.

The slope is about 45 degrees I'd roughly estimate, and facing North West.

@MaryLennoxsScowl my sister has 8 horses actually. New mission is now convincing my DH that bags of manure won't irreparably stink out his van because that seems like a fantastic idea. Chickens are on my wishlist for next year too! I want happy hens, so don't want to buy them until I can afford a big outdoor run.

Another way to get free mulch for the kind of area you're talking about is to use fallen leaves. I gather them by the sackful from the lane and wooded area outside my house. Then I just shred them (Screwfix and DIY big box stores sell shredders from about £100) and scatter them straight over the soil.

You have to shred them or they'll form a thick mat and it's best not to put it around plants (because the rotting down deprives the plants of nitrogen) but it would be perfect for your subsoil area. A couple of years of thick mulching and your soil will be completely different.

Thank you @SeaAndStars - I'm rapidly expanding my garden wishlist the more I learn!

So far we've spread some compost & grass clippings from the lawn on the area, and I chanced my arm sticking discounted broad beans & mustard seeds in a big patch today. Even if they don't grow, my 3 year old was kept entertained for the afternoon digging holes. If they do grow, my plan is to use them as green manure. 🤞🏼 My DH vetoed the transport of the horse manure, unless we can buy his much wanted trailer. Our budget says no for now, sadly.

I'm eagerly watching our home compost bin to see when dirt will appear too! Ours is a cheapie that we got second hand off family, so I'm not expecting it to be a quick process.

Put your postcode in here to see if your local council partners for cheap compost bins: https://getcomposting.com

My DD used to go horse riding. I’d take along a shovel and fill bags of heavy duty bin liners with manure. I’d double bag and take from the bottom of the heap, so it was already well rotted.

Buy the apple trees this year and grow them on in pots - much cheaper and they’ll be used to your environment.

I haven’t had much success with wildflowers (mine became infested with nettles, thistles etc) so would go for the clover to enrich the soil and crowd weeds out.