Many urban gardeners find it difficult to control soil conditions in their limited space — terraces, verandahs and small backyards. Moreover, the prospect of having worms, bugs and the soil-borne diseases that come with soil, so close to their living space, can be a deterrent. Fortunately, there are several options for those who want to grow their own vegetables in a soil-less environment. Last month, we covered the soil-less mediums available in the market — sand, gravel, vermiculite, and cocopeat that can replace soil if nourished with fertilising solutions. Another such medium is water. There are many methods of using water as a growing medium. Of these, Deep Water Culture (DWC) is considered to be the easiest and most efficient system of hydroponics — the growth of plants in soil-less mediums. In this method, the plant roots are submerged in an oxygenated water-based solution, which contains essential nutrients and minerals needed for healthy growth.
Getting started
Though the other soil-less mediums can be used in any type of container or even a garden bed, DWC needs a two-tier system for the plants. The plants grow in a perforated tray with a container of water below supplying moisture and nourishment. Larger plants (tomato, ladies finger, capsicum) are best grown in deeper 12-inch buckets; smaller plants like lettuce, spinach, strawberry and herbs can be grown in flatter trays. Materials required for hydroponics can be sourced from larger nurseries or online garden sites. But they can also be fashioned at home: for a large ‘growing raft’ to be placed over water, use thermocol sheets with holes cut in for the plant, which is placed in small re-usable plant baskets. Old buckets, sieves, plastic containers can be recycled for plant containers. Greens grow especially well in a plastic wire basket placed over a bucket of water. A combination of alternate mediums — large buckets and troughs with dry mediums (as detailed in Part 1) for taller plants with dense foliage; and water-based system for smaller plants can be used for a diverse range of crops in your kitchen garden.
Ideal Plants: Tomato, cucumber, ladies finger, spinach, strawberry, amaranth, methi , coriander, herbs and microgreens.
Sow Seeds: This can be started in degradable plugs placed in a tray, or in a seed tray filled with cocopeat. Mix a dilute organic fertiliser into water and pour just enough into the tray to wet the medium; once the plugs are moist, place the seed in the centre of each. Place the tray in a warm spot to germinate. Once the plants have sprouted and reach the stage for transplanting, move the entire plant to the growing raft or buckets kept in a sunny location.
Natural fertilisers and herbicides
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Maintenance and care
This method of gardening needs minimum care; in the absence of soil, there is little chance of attacks by worms and insects. However, the water needs to be oxygenated daily, as oxygen is vital to enable the roots to suck in nutrients and fight off disease. For a small or medium-sized garden, this can be done manually, by splashing the water vigorously to aerate it. Larger areas may need an air pump similar to those used in fish tanks to pump in oxygen.
Harvest
When the plant is ready for harvest — fruit or leaves, it is a simple process. Pluck the fruit or flower as it ripens; if the leaves are to be harvested (greens, lettuce), remove the entire plant from its growth space.
