by Michael Smith (Veshengro)
Rooftop gardening has gained popularity everywhere, particularly in urban areas where people have limited space for planting flowers and crops. Gardening is not only a worthwhile pastime, it is also beneficial for the environment.
Rooftop gardening has a number of different requirements to ground level and even general container gardening. You obviously will need a roof that is flat – sort of – for no flat roof is really 100% level flat; the water would not drain off otherwise.
Green roofs are becoming very popular in the UK as much as in other places but there are green roof and there are green roofs and rooftop gardening is not, necessarily the same as green roofs.
Picking plants that will do well there is one of the important aspects but then that is, in a way, no different than when you garden at ground level.
If you are planning to grow vegetables on top of your roof during the cold season, good options would include greens, peas, radishes, and broccoli. Hardy summer food crops on the other hand are perfect during the warmer seasons. These include strawberries, tomatoes, cucumbers, and squashes.
As with all gardening the right location is important. So, select the perfect spot. Like in the garden on the ground choose a spot in the roof that enjoys about six to eight hours of sunlight per day. It is best that there is a shade to protect the plants during the hottest parts of the day, which is generally from 10 am to 2 pm, or thereabouts.
With gardening on the roof it is important to bear in mind the load bearing capacity and -capability of the roof you are using. Your garden will give extra weight to your roof and even though the structure can take on extra weight, soil and water can get quite heavy and that especially during prolonged periods of wet and with snow water.
You may want to consult a contractor or architect for this matter as you would want to find out if the building can take on the additional weight from your rooftop gardening activities or not, if to ensure that you’re keeping within the safety perimeters while you engage in the activity of growing plants.
Also, to keep things light, go for plastic and fiberglass containers. Stay away from using paving slabs, raised beds, and terracotta planters and (large) pots. You may not have much choice as to soil for while you can get lightweight “potting” soil this is (i) rather a costly way of doing it and (ii) your plants may not like it in the long run.
The best advise would be not to overdo it on the roof as far as the amount of planters and plants are concerned. Some roofs are designed to take a lot of load, as are some of the tops of apartment blocks in the cities. The flat roof of your house may not be geared for such loads and definitely not the roof of your garage.
Since the rooftop garden is windier than a usual garden, you would need to install windbreaks. You can try using trellises or any other latticed windbreak for the garden. These are important to slow down the strong flow of winds that can damage the plants. It is always better to use latticed windbreaks that disrupt the flow of wind rather than completely stop it. This is because solid windbreaks can easily be damaged than latticed ones.
Trellises used as windbreaks are also great on which to grow climbing plants such as beans, peas and such like. In fact anything that wants and needs to climb and you can also use them to add just interesting color by using them to allow sweet peas (they are not edible) to grow on them.
The flowers from the such sweet peas and other flowering climbers will also attract pollinating insects and it is important that they get onto your roof.
Another interesting and important thing to consider is how you are going to water your rooftop garden. It may be rather unwise to bring heavy buckets of water to the roof every time you need to water the plants. Not only is this tiring, tedious, and even dangerous to your health, it is also time consuming.
The smarter option would be to install a water storage system or an automatic watering system for the rooftop garden. While this would mean extra cost on your part, the investment would be well worth it, as you no longer need to bring heavy loads of water to the top of the building.
I would suggest, however, that the water storage system be not installed on the roof. Water is rather heavy; in fact 1 liter = 1kg which means that about a quart of water equals 2 pounds.
There are, however, electric pumps available for water butts that produce the same pressure and more than do the water mains and thus it would be an investment worth making. They do not, actually, are that expensive. Rainwater butts probably cost you more than the pump, unless you create your own butts from junk.
Now, happy gardening and don't fall off...
© 2011
