It’s that time of the year again when many of us will start tinkering about in the garden. Meanwhile the urbanites will just look on with envy… not unless they have a patch of flat roof or a terrace at their disposal.
Growing food on the roof is not at all difficult and there are many green roofs in large cities. Roof is an ideal place to grow your own food – it usually gets even more sun than any old garden.
The first thing to do in order to start to grow food on the roof is to inspect the structure. Will it be able to bear the weight of the soil and plants? If it’s a concrete roof or one with strong joists it should be all right, although, if you’re building a large roof garden, you should probably consult a structural engineer.
You decide the scale of your roof garden! You can fill the whole area creating a substantial garden – this would require another layer of membrane (or go with oldroyd developed specially for green roofs), otherwise the roof would eventually develop a leek… it’s a pun – leek, leak…no? ok, moving on. An easier and cheaper option is to create a patch from a shallow DIY wooden box lined with a membrane or a sheet of ruberoid. An even cheaper way to grow food on the roof is to place planters and pots on the roof. If you choose to go with the planters, make sure you’ve provided a decent drainage – put something underneath the pots to make sure the water can easily escape through the hole.
The main thing about the soil that is used on the roof is that it has to be as light as possible. Otherwise when it’s raining, the soil can get too heavy which means too much load on the roof structure. The easiest way to make the soil lighter is to add perlite to the mix – it is a form of volcanic glass and you can buy it at almost any gardening centre. Compost with large particles is another main ingredient that will go in the mix because compost is not as heavy as the soil yet it provides the plants with all necessary nutrients.
As for the plants, there are very few limitations as to what you can grow on your roof. The best bet is to choose something with a shallow roof system. I’m not sure you could grow carrots and beetroot up there. The ideal candidates are all the herbs that you can think of and tomatoes, peppers, beans, zucchini etc. One should aim at creating gardens of Babilon – we all know what happened to them. Green roof is an amazing way of approaching a sustainable lifestyle. If you’re not sure, start with just a couple of planters and then scale up as you become more and more sold to the whole idea of growing your own veg.
The amazing pic of a roof garden has been taken from the Hollingdean Community Centre. Hop over to their site to have a look at what can actually be done with a flat roof!