From the simplistic—potted plants and containers brimming with blooms—to sophisticated seating arrangements, walking paths and plantings, people are slowly learning to live in compact spaces, not giving up on their love for gardening. Here is the trend of rooftop gardening, also known as ‘green roofs’, which not only gives your rooftop a new lease of life but also has several environmental benefits. What makes this trend, even more, environment friendly is the growing awareness about eco-gardening.

Most of us have a roof, but how many of us actually use that roof for anything besides shelter and end up sulking about lack of space available for gardening? Sanjeev Suri from Defence Colony maintains and grows bonsais and vegetables as a passion and puts in his heart in every plantation. Not worrying much about the space, he just needs a small area to plant yet another life and he feels that a rooftop is the best place for plantation. “Sun rays lead to warming up of concrete, asphalt, etc much faster than trees, plants and greenery. A roof garden, however, can ease the burden on homes, by keeping the rooftops cooler. What better can it be to have home-grown vegetables in your meals and beautiful flowers decorated in your house from your own garden,” Suri smiles.

Though, it is best to go for organic manure which can be very well made out of kitchen waste. Here comes the concept of eco gardening.

What is eco-gardening?

Bella Gupta, the convenor of All India Kitchen Garden Association, has spent a decade on eco-gardening. “Grass lawns in houses and offices often require chemicals and frequent maintenance. The concept of eco-friendly gardening, which includes replacing the grass lawn with native wildflowers, bushes, and trees, provides food, shelter, and cover to maintain healthy eco-systems, thereby reducing one’s time, cost and labour, says Bella.

The process has been thoughtfully planned as it encourages the growth of bird- and bee-friendly plants, use of home-grown compost and used tea fertilisers, incorporating discarded plastic bottles and containers, harvesting rain water, and using aquaponics (the growth of plants with fish).

Types of rooftop gardens

Depending upon the structural design, rooftop gardens are generally divided in two types:
Extensive rooftop gardening: It is generally lightweight gardening which requires little or no maintenance. The characteristics are:

• The green cover acts another layer to the roof
• Can be installed on flat as well as sloped roofs
• Drought prone plants are used that can handle harsh conditions like wind and sun exposure

Intensive rooftop gardens: Perennial flowers are mostly used in such gardens, having the potential to bear fruits and food. The other characteristics are:

• Generally installed on flat roofs with the vegetation either covering the entire area or in containers and raised beds
• A stronger roof structure is required due to the added weight containers and beds
• More maintenance is required because of the greater variety of plants.
• Other considerations for an intensive rooftop garden include condition of roof, structural and weight capacity, access, cost, irrigation, and drainage.

Have the right containers

Although terra cotta pots look good, they are too porous to conserve water under rooftop conditions. Plastic pots do a much better job. Bella adds, “Do not use anything smaller than 20 cm (8 inches) in diameter because there isn’t enough soil mass relative to the exposed surface area in a small container to hold much moisture for very long. It is best to use plastic pails that restaurant food supplies come in for a single tomato, pepper or eggplant. Poke a few holes in the bottom, add an inch of gravel for drainage, covered by a filter cloth to prevent the sold from coming out the bottom. Fill it about 2/3 full with a light weight soil mix, leaving room for much, and you have a perfect rooftop garden plant container.”

You can also build wooden planter boxes or adapt packing crates. To do this, line with plastic, cutting a few holes in the bottom for drainage, and also fit with insulation on the inside. Suri adds, “No matter what kind of container you use, do not fill it to the top with soil. The lover soil level will enable the plant to get some wind protection from the container itself, as well as leaving enough room for a generous layer of mulch (at least 1 inch).”

Benefits galore

UV radiations shorten the lifetime of a roof and these gardens act as a barrier between the rays and roof. Vouching for this trend, an avid gardener Indu Kaushal, a saket resident says, “Transplanting gardens to the rooftop can be beneficial gardeners who have bushes, shrubs, or other plants that are prone to attacks from pests and small animals. Moving plants up higher can reduce vermin, as well as prevent the human or animals trampling of delicate plants that can occur on the ground. Rooftop gardens can also add aesthetic value to a home.”

Pre-requisites for rooftop gardening

Soil:

It is best to use lighter soils as

It is best to use lighter soils as wet soil is heavy for the roof. One can opt for soils such as perlite, vermiculite, peat moss and coconut husk fibre and rockwool pad. They keep the plant stabilised.

Fertilisers:

Opt for organic or homemade manure that can be made out of wet kitchen waste.

Water:

A tap on your rooftop having moderate to high water pressure.

Plants:

Use hardy or indigenous plants as they can handle harsh climatic conditions. Chose plants that don’t require much root space as higher soil depths make the containers heavy.

As per garden type:

For an extensive garden, mixtures of grasses, mosses, sedums, sempervivums, festucas, and irises—plants native to drylands, tundra and alpine slopes are best suited for this rooftop environment. Intensive gardens can support just about any type of plant, provided that special protective precautions are taken for more sensitive plants such as using windbreaks and shading.