The success of any zombie garden is built literally from the ground up: your garden will only ever be as good as the soil you grow it in. Soil is what holds your crops in position, what feeds and waters them. It doesn’t come in just one variety, either. The kind of soil you have will make all the difference to what kind of food you can grow and how successfully, so you should take time to assess what kind you have.
In gardens and open spaces like allotments, check your soil by doing what’s called a pit test. Once you’ve picked a likely spot, take a spade and begin digging a squarish hole in the ground.
To start with, the soil will be reasonably dark: this is the living, nutrient-rich layer known as topsoil, where plant roots will be happiest. As you dig deeper, the soil will change colour, usually getting much lighter. This is subsoil, which isn’t nearly so root friendly. With less than 15 cm of topsoil, growing any food crop other than shallow-rooters like herbs or lettuce won’t be easy, so look elsewhere.
If you’ve been sensible and looted either a battery-powered soil probe or a soil-testing kit, use it to check the soil pH, i.e. how acid or alkaline it is. If your probe shows ‘pH 7’, the soil is neutral; above 7 is alkaline; below is acid. Most zombie-garden plants will grow happily in soil with a pH between 6.5 and 7.5. But poorly drained, very acidic earth – the kind with a pH of 5.0 or lower – won’t support the kinds of plants a zombie gardener needs to survive. Again, look elsewhere.
Next, moisten the soil in your hand and see if it will roll into a ball that holds its shape when you drop it. If it basically behaves like Plasticine, the soil is clay. This is made of tiny mineral particles that cling together in sheets; it holds nutrients well but will get wet in winter and dry to rock hard in summer.
If the soil won’t roll into a ball at all, it’s sandy: made of larger mineral particles with lots of air space between them. This means that water drains through it very fast, and keeping your crops watered and fed will take more time and energy – time and energy that after the dawn of the dead would be more usefully spent:
■ Patrolling boundaries and doing martial-arts training with a sharp stick.
■ Growing closer as a community by sharing stories about your lives before the apocalypse.
■ Raiding other settlements and facing heavy moral decisions about whether to kill all the occupants. Then killing all the occupants, with sharp sticks.
If the soil ball holds its shape until you drop it and then breaks, it is garden manna: loam, a light, rich, friendly mixture of mineral particles large and small, which you can plant in all seasons and which doesn’t dry out too quickly.
A last note: according to Cranfield University’s brilliantly useful soil-mapping Land Information System, the area around the nuclear plant at Hinkley Point is made of loamy sand, with a peaty surface, high groundwater and a medium to high carbon content 16. This means it is really fertile. Still: don’t go there.
On balconies, roofs, prison yards or any place where growing has to happen in containers, you’ll need to source some kind of growing medium. The good news is this means you can control its quality; the bad news is you have to loot great big heavy bags of compost.
For successful vegetable harvests, you’ll need your growing medium to be airy, able to drain well, and to contain plenty of a vital ingredient known as ‘organic matter’ (OM). This is a rotted mix of dead plants and animal matter – straw, dung, fallen leaves, zombie flesh – that helps hold water, feed soil microorganisms and provide plant nutrients. Multipurpose compost will be the right texture and have a high proportion of OM; you’ll find it in just-about-luggable twenty-five-litre bags at garden centres and DIY stores. Green-waste compost, the kind piled up in bags for pre-apocalypse sale at council rubbish and recycling centres, can be a bit more hit and miss, quality-wise, but is still worth grabbing. You might also come across pure bagged topsoil, though this is unlikely to have much OM and is really heavy: don’t try to loot it on your own.
How many bags will you need? You might be surprised by the sums. One piddly container 30 cm wide and 30 cm deep will swallow up the entire contents of a twenty-five-litre bag of compost. For a single square metre of raised bed 25 cm deep, you’ll need to carry home a hefty ten bags. But look at it this way: by the end of the apocalypse you’ll be really ripped.
