by Lionel Weerakoon

A home garden is a piece of land around the dwelling with clear boundaries and it has a functional relationship with its occupants related to economic, biophysical and social aspects. A home garden often consists of a mixture of annual and perennial crops, sometimes including small livestock. On account of the vertical structure with different canopy depths of various plant species, the home gardens are most often referred to as a ‘multi –species, multi-storied cropping system’.

Numerous terms have been used by various authors to describe this system. These include, for example, mixed garden horticulture, mixed garden or home garden, Javanese home garden, compound farm, kitchen garden, household home garden and home garden agro forestry system among these. The structure and management of a home garden varies from place to place, depending upon ecological, socio-economic and cultural factors.

The development and maintenance of a home garden is a collective effort of family members. The cultivation of varied species of plants around the house is usually unplanned. One of the main reasons for growing trees around the house is to provide shade and create a favourable micro-climate for the household, especially during hot weather.

The location where a crop is to be planted in a home garden is based on the characteristics of the plant and its value. Vegetables are usually grown in open areas or, for convenience, at the back and sides of the yard close to the house. Kohila with a high water requirement are planted close to the well. The crops that need shade such as inguru, kaha, kiriala etc are grown under the trees, having a broad canopy.

Tall trees such as teak and mahogany are often planted along the property fence, while fruits or food crops tree are planted within the boundaries. Trees or shrubs grown in the home garden could be grouped into several groups based on their functional value. These categories are 1. Ornamental, 2. Vegetables, including leafy vegetables 3. Medicinal, 4. Spices. 5. Fruits 6. Starchy food crops, such as tuber crops, innala, kiriala, raja ala, kidaram etc. 7. Fodder 8. Timber 9 Firewood. 10. Shade/soil conservation.

The most intensive home garden systems in Sri Lanka are found in Kandy and Matale Districts known as ‘Kandyan forest garden’ and are well known the world over. They are dominated by six species; jackfruit, coconut, mango, arecanut, bread fruit and spices. Very similar forms of home gardens are found in other parts of the wet zone, both in the hill country and lowland areas.

In the low country, home gardens contain various fruit trees, including rambuttan and mangosteen. Depending on the availability of moisture, the crops grown in home gardens in the dry zone are different. Coconut, mango, jack, papaya, orange and guava are amongst the most common species found. Indigenous species including halmilla, sandalwood, teak, tamarind, and margosa form substantial private planting in farmlands.

Estimates claim 26% of all firewood, and 39% of timber needs are produced in home gardens. Home gardens in the Kandyan area form some 4.1 % of the natural tree cover, compared with over 24.9% forest cover in 1980s. Although the population is increasing in Sri Lanka, the total area under trees in Sri Lanka is actually expanding. This is because of the great interest in home gardens. The results of the land use studies for the Forestry Sector Master Plan showed that the area under home gardens has been increasing by about 3% annually since 1980 and 1992.

Sri Lanka’s increasing wood, food and fruit demand could be met or at least strongly supplemented by enhancing the utilization of existing home garden systems and intensifying land use in order to expand the various forms of home gardens. Adoption of better soil management techniques, such as compost use, mulching, soil and water conservation, thereby mitigating moisture stress experienced during dry periods and minimizing soil erosion. Use of wastes, such as green leaves, or decaying leaf, cow dung or cow urine and liquid organic fertilizer are some of the notable practices that can be utilized to improve soil fertility for sustainable crop production in home gardens.

Soil Care and Water Conservation in Home Gardening

Soil care, water conservation and pest control are the most important activities in Home Gardening. This article deals with the first two. Soil loss due to soil erosion leads to depletion of organic matter, reduction of soil microbial population and moisture loss in surface soil.

Home gardens located in the uplands are particularly prone to soil erosion. The home gardens in flat lands have different problems such as water logging. The following are some guidelines of technologies that are used by the home gardeners in different agro-climatic regions in Sri Lanka.

Engineering methods, establishment of bunds

This is used in the dry zone home gardens, where there is low rainfall. Usually at every 20-30 meter intervals bunds and drains are established. The width of a drain and bund would be between 60-80 cm and 50-70 cm respectively. Contour or graded bunds and drains are constructed systematically in order to facilitate collection of runoff water into the drain and retain organic matter within the land so that only the excess water will drain out of the land.

The earth bund will act as a barrier so that it reduces the overland flow rate of water. In case of flat lands, it would be sufficient to have only the drains to let water out of the land. Otherwise it can lead the crops to get damaged due to water logging during the rainy season. The downstream drains should be finally connected to a common drain and let water drains out from a comer of the land. If there are any natural water ways running across the home garden, physical barriers should not be established to block the flow.

The most suitable practice to bunds and drains is growing grasses or bushes with a spreading root system on either side of the bund, especially on the side facing the direction of water flow. Savandara, (Vetiver), Citronella or bushes like Pavatta are most suitable, due to their soil binding effect_ Such grasses or bushes are to be cut time to time and applied to the land as green manure or mulch.

Stone-terracing is practiced in home gardens cultivated ‘with annual or perennial crops for soil conservation. As this is a traditional practice. people are familiar with it. Stone terraces 25-30 cm wide and 50-75 cm high may be constructed across the land by carefully placing the stones of different sizes collected from the home gardens. The distance between two terraces does not usually exceed more than 5m although it may vary depending on the gradient of land.

Stone terracing lock and spill

This method is practiced for soil conservation on sloping lands exceeding 40% gradient before cultivation of annual or perennial crops. The size of the drain should be 60-70 cm wide and 30-40 cm deep. At every 4-5m, soil bunds 30-40 cm wide and about 25cm high should be left across the drain. Organic materials and sand particles in water flowing across the land will settle down at the bottom of the drain as a result of reducing its flow velocity. This settled material in the drain, could be collected and returned to the land. Lock and spill and bund barriers could be constructed by the use of stones available in the home garden.

Biological method, hedgerow cultivation

In the dry zone, hedgerow cultivation is known as Avenue or Alley cropping and in the upcountry and mid country wet zone as SALT (Sloping Agricultural Land Technology) system. Both these methods, in addition to preventing soil erosion, will provide green manure for the home garden as well as fuel wood for domestic use. For this reason, both these practices can be popularized among the home gardeners. Sometimes, the leaves could supply fresh herbage requirement of livestock.

Avenue or alley cropping

This hedgerow method is suitable for flat or slightly sloping home gardens in the dry zone receiving low rainfall. Legume species such as Gliricidia septum should be planted at 50cm distance along the contour or across the slope of the land. Along the hedgerow Gliricidia should be established 4m apart. The space between Gliricidia along the hedge may be grown with Vetiver or Citronella as a measure to minimize soil erosion. In the 4 m wide alleys formed by Gliricidia hedgerows, seasonal crops, tuber legume crop grown between Gliricidia hedge-rows crops, or sometimes fruit crops could be cultivated.

Before planting these crops one to one and a half years-old Gliricidia hedgerow should be cut back or lopped to a convenient height. The toppings and tender branches could be spread in the alley between hedgerows and once the leaves are shed, tender shoot and leaves could be incorporated into the soil as green manure or left on the surface as a mulch.In alley cropping, Gliricidia is commonly used as the hedgerow as it is a perennial, fast growing legumes shrub species, capable of fixing atmospheric nitrogen and tolerant to repeated pruning. Furthermore it has a deep and a spreading root system which can absorb moisture and nutrients from deeper layers of the soil. Leaf and tender shoots should be left after pruning trees are incorporated into the soil as a green manure, which is adequate to sustain growth and yield of seasonal crops.

Generally, pruning of Gliricidia should be done about 1.0-1.5 m above ground but pruning height may be adjusted according to the needs of farmer. Trees could be pruned three times/year during the Maha season (September-December) and twice during the Yala season (April-May). After pruning foliage could be incorporated in to the soil and wood biomass as a source of fuel wood, especially for cooking. This is becoming scarce resource in rural areas. Crops grown in the alleys include: vegetables, tuber crops, pulses, cereals, papaya, banana, and other fruit crops.

SALT method

This method is recommended for home gardens in sloping lands up to 60% gradient in the mid country wet-zone and hill country where double hedgerows with 20-25 cm between two rows are established along the contour, keeping a distance of four to five meters between double hedgerows.

Up to an elevation of 1,000m, Gliricidia is generally used as a hedgerow species but above this, Tithonia and Erythrina can also be planted as hedgerows. To minimize soil erosion, the space between two rows of the double hedge could be filled with stones and any other solid material. Rest of the operations are similar to those of avenue cropping except that trees are cut back about half meter above ground to increase the quantity of leaf biomass.