Andrew Marsh’s 1898 bluestone villa in Adelaide’s eastern suburbs has a rather wonderful secret.
Around the back, past the immense golden elm but before you reach the swimming pool, you’ll see a ladder leading up into the eaves.
If you climb the ladder up to the roof (a precarious task with a full cup of hot coffee), you’ll find a most unusual vegetable garden. In mid April, two raised beds overflow with tomatoes, zucchinis, capsicums, newly-planted garlic, beetroot, spinach, chillies and even a solitary carrot left over from last year, while smaller pots hold sage, parsley and basil.
Impressed and fascinated by this novel kitchen garden, I interviewed Andrew to find out more.
What made you decide to grow vegetables on your roof? And how did you create the space?
I knew I couldn’t grow vegetables in the backyard because of the large trees that shade it, so I built the decking on the skillion roof with a vegetable garden in mind. The decking had to be strong and capable of bearing about 15 tonnes in total.
I’m mechanical engineer and allied with that I have my hand in sustainability, so I was aware of what was needed and what was going to work. I rehearsed in my own mind how I was going to get the soil up there once the decking was built and that was literally with a block and tackle, bucket after bucket. It took a whole day to get two tonnes of soil up there to fill just two raised beds.
The skillion roof was a bit of an accident. I misread my own drawings when I was designing our home extension. When the builder put in the roof structure I thought, oh my God, this roof is so much lower than I intended. I was hell-bent on disguising the new rear of the house. Now I’m proud I designed this low roof than enabled a roof garden to be built.
Describe how you created the raised garden beds?
The beds are made from corrugated iron which I cut from pre-purchased lengths using an angle grinder. They’re lined with rock wool with a tarpaulin barrier between the rock wool and the soil and a drainage system in the bottom. Each bed has a dripper system on a timer but they also sometimes need supplementary hand watering on hot days. The soil is a commercial vegetable mix which I enrich with home-made compost and manure from my hens. I made a structure over each bed from electrical conduit which I cover with shade cloth in hot weather.
What do you grow up there?
We’ve had two reasonable crops of tomatoes and plenty of brassicas. Root vegetables seem to do better than the surface ones; the beetroot was outstanding, parsnips less so and we had plenty of carrots. I plant everything on top of each other; I’ve got a whole packet of beetroot seeds sown into half a square metre.
We eat from the garden every day. We have entire meals where I might scramble some eggs from our chooks and throw in chopped up tomato, spinach, zucchini and capsicum that I’ve just picked. Apart from a little bit of olive oil it’s a meal taken completely from the garden minutes before we eat it.
What advice would you give a prospective roof gardener?
You need a flat area that’s fairly private, not overlooking anyone else. I had to get another engineer to sign off the steel structure that was going to support the decking. After that was done, the council signed off without a hitch. The roof is designed to take four planters but if I did that there would be no room to take people up, and we do like to take people up there. People are fascinated by it.
What has most surprised you about your roof garden?
The biggest surprise is that it’s such a lovely place to be, especially when the sun is setting. There’s lots of light up there and uninterrupted views of the hills. It’s a peaceful, private spot. Whether sitting there with a mug of tea or taking friends up and having canapés before a dinner party, it is just a great spot. I didn’t expect that it was going to be another room, an outdoor, gardening room.