Design Roof Garden Case Study Analysis

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2.6 Plants

What can company plants up there, will depends on the availability of roof space and weight load. Location, wind, rainfall, air pollution, building height, shade, and soil depth are all factors in determining what plants can be grown and where. The ability of plants to survive on a green roof is directly proportional to the amount of maintenance time and budget allocated to the project, particularly in the first two years when they are getting established. The company will plant most of favourable vegetables and herbs in any of three types of deep trays. Even still, not everything does as well as it would on the ground but most of them survive. Here's the list of what the company is planning to plant: Herbs, Lettuces, Bush beans, Pole beans, Tomatoes, Snow beans, Spinach, Peppers, Carrots, Cherry tomatoes and Mustard greens. The majority of the plants will be source from the nearest fruit and vegetable shops and the local nursery.

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Containers carrying plants

Green roof habitats create open spaces or areas of natural habitat within the Kgoshi Mampuru correctional services which can attract interesting creatures, such as butterflies, millipedes, frogs, lizards, and birds. It will be interesting to note that the presence of true bugs and butterflies indicates that a relatively healthy ecosystem is starting to develop on the green roof.

3. Maintenance

Maintenance is vital on the roof gardening to enhance the condition of the plants. If the roof gardening is not properly maintain, it can become an ugly thing. A poorly maintained roof gardening is also less functional in terms of providing food and performing other ecosystem services, such as storm water attenuation, temperature reduction, noise insulation, and improving air quality. The following aspects are taken into consideration when preparing the roof gardening maintenance program:

3.1 Irrigation

New plants must be watered two to three times a week for the first 3 months until the plants become established. Thereafter, the plants must be watered on an ad-hoc basis. With the rising price of water and the probability of not having availability of water in the future, it is becoming necessary to reduce the consumption of potable water, especially for watering plants. There are two types of water system which can be used as described in the below table.

System

Description

Rainwater harvesting

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- Provides high quality water.

- Can be collected from roofs using gutters, which feed into a container, and pumped up to the roof garden

- Containers should be mounted on a secure, level platform, and include an overflow pipe for heavy rainfall.

- Ensure roof and drainage system (gutters etc.) are in good condition – clean and free of holes.

Reusing greywater

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- Refers to waste water from basins, showers, air-conditioners and baths.

- Can be collected in a container and pumped up to the roof garden habitat or collected by hand.

- Unlike rainwater, greywater is not seasonal.

- Avoid watering edible crops or fruits with greywater.

3.2 Composing and garden waste management

The company has a sustainable waste management programme which form part of the maintenance programme of roof gardening. The golden rules of responsible waste management are to reduce, reuse, and recycle:

Reduce: It is the amount of waste produced. For example, choose products which do not have excessive packaging.

Reuse garden materials again and again. For example, use durable refuse bags which can be used over again instead of thin plastic bags which can only be used once.

Recycle or convert garden materials into a new or different form (e.g. composting).

Composting is an easy way to reduce the amount of organic waste which needs to be disposed of. This process breaks down organic materials, such as fallen leaves or leftover food, releasing and making available nutrients essential for plant growth. This compost can then be used to enhance the quality of the growing medium by returning vital nutrients.

The amount of fertiliser and the frequency of application are dependent on a number of factors, such as plant type, soil composition, soil depth, and amount of watering. Ideally, however, the use of fertilisers should be minimised where possible, and if fertilisers are to be used, organic fertilisers are preferable to inorganic fertilisers. The company use the manufacturer recommendation when applying the fertilizers.

3.3 Control of weeds

Weeds refer to plants which grow where people do not want them. In roof gardening, the primary source of weeds will be the organic growing media, such as compost and potting mix, and the soils that the plants come in. The company has two methods of controlling weeds which are physical removal or treatment with herbicide or weed killer. In most cases the company prefer, physical methods, such as hand pulling, which are the most effective for roof gardening. Weeds should ideally be removed as soon as possible before they are able to seed. The use of herbicides is only recommended as a last resort because these chemicals can impact negatively on the birds, butterflies, and other insects, attracted to the green roof, as well as potentially killing the plants within the roof gardening.

3.4 Controlling pets and diseases

The company try by all most to reduce the use of herbicide as there are dangerous to the plant and people. The company reduce the use of herbicide by doing the following when preparing to plant:

- By selecting pest resistant plants which are suited to local conditions.

- By ensure that planting areas have been sufficiently prepared.

- Attempt physical pest/disease control methods first (e.g. remove