Watering your Plants
All container-grown plants must be watered regularly because unlike a garden there is no earth continually rained upon from which they can get further supplies of water. Remember this when choosing your plants and planning your balcony or terrace. Is there a water supply in the vicinity or will you have to carry watering-cans to and fro? How much will you have to water the plants depends on a number of factors:
How much water the plants need: Plants with large, soft leaves such as cottonweed (Abutilon theophrasti) or African hemp need a lot of water because of the surface area of their large leaves. Plants with fleshy, leathery or small leaves evaporate less water or can store it better so that they will more readily tolerate periods of drought. This includes agaves, purslane, laurel, citrus plants, myrtles and rosemary.
Containers: Small containers need to be watered more often than large containers, and plastic containers retain moisture longer than clay or terracotta.
Soil mix: Sandy soils dry out more quickly than loamy ones.
Weather and position: In sunny weather, dry air conditions or windy weather, plants will need much more water than in humid or sultry weather conditions, or if they are placed in a sheltered location.
The right way to water
• Check the water situation every day even in rainy weather. This is because much of the rainwater runs off the dense mass of leaves and never reaches the container.
• It is best to water in the morning or evening when it is not too hot. This gives the water sufficient time to reach the roots without evaporating before it gets to them.
• Never water the plants in the hot midday sun. Water directly onto the; do not pour water on the plant which will cause unsightly spots on the leaves, as well as encouraging mould and fungal infections to develop.
• Frequent, superficial watering is not so effective as a good soak, so it is better to water less frequently but more penetratingly. However ‘thirsty’ plants like angel’s trumpets may need watering twice a day in very hot weather. .
• In the case of succulent plants, such as agaves, you must wait until the soil is completely dry before watering.
• Waterlogging must be avoided at all cost because most plants will not tolerate it.
• If a container or pot has completely dried out, it is best to give it a good soak. Leave the plant and container to soak in a basin or tank until there are no longer any bubbles coming to the surface.
• You may be lucky enough to have a water-butt to collect rainwater. This is less cold and less alkaline than most tap water. It is important to use soft water such as rainwater for all lime-hating plants such as heathers,and hydrangeas. If you have no water-butt you can buy water-softening agents in specialist shops.
Many of the plants which are suitable for growing in containers will tolerate short periods of drought. They usually recover very quickly after generous watering. However, this should not be allowed to happen too often.