Well, it’s not going to be easy, but it is definitely possible! One of the biggest challenges when it comes to urban gardening is the soil. Urban soils are quite different from natural conditions that plants like forest soils. Forest soils are rich in organic matter, which helps to retain moisture and nutrients. In contrast, urban sites frequently have pollutants: building waste is common, heavy metals, lots of compact clay. Compact soils are considered an engineering substrate and are what’s under all our roads: but terrible for plants. So plant roots can grow through you can break up compact soils using a plough if you have a tractor (not always possible in a city!) a rotivator, a high pressure airline or even a spade as a last resort. Where this is not possible install an area of root friendly non compact growing area ABOVE the existing plant root zone by adding compost onto the root zone and a layer of woodchip on top. The roots will rapidly colonise the new area and the plant will get a new lease of life. Also remember soils release carbon when they get dry so lock in the carbon and moisture content by mulching with deciduous tree branch woodchip (not the horrible chemically treated stuff you get from the garden centre). Water vapour is a greenhouse gas, the more you can retain on your patch of Earth the better.
You might be surprised but most plants have the great majority of their roots on the surface ie in the first 0.5m of soil because they need oxygen. Also there are lots of plants that do well in really harsh environments e.g. moss. Have you ever noticed how moss can completely dehydrate and survive. Not many plants can do that. That’s why you see moss on walls. It gets really hot on a wall in high summer. It’s a battle of attrition. Moss can colonise walls very few other plants can do that. The succulent Seedum can do this as it stores water in little fleshy compartments like a cactus. So there are two plants that are handy for planting in a harsh environment and require basically zero care.
Other things that will grow in a very thin layer of soil might be Grasses, Nettles, Wood Avons, Elder. Growing things in your neglected patch is probably far easier than you might think: lots of plants are adapted to thrive in poor soil conditions and even better news you might not even have to plant anything: you can just rely on windblown seed germination or bird based distribution. You will have to do a bit of weeding but really just spread a bit of mulch and let nature work away. If you do decide to try and grow more convention garden centrey type fancy plants then that will be more difficult but actually it’s dead easy if you’re not that fussy and will look nice and natural.
If you need help with a project we would be happy to advise and assist!
