Post category: Watering


Outdoors, plants depend on natural rainfall but watering can be necessary if rainfall has been inadequate, or if a plant’s root system is not properly established. Seedlings, young plants – especially vegetables – and plants growing in shallow or dry soil, are principally at risk. Watering is obviously necessary indoors. The sections on Greenhouse Growing and House Plants go into some detail.


Plant requirements


Normal summer rainfall is at least 50 millimetres per month. This amount closely matches plant requirements. Twenty-five millimetres of rain is equivalent to almost 25 litres of water per square metre. If there has been no rain for a week, plants need about 12.5 litres per square metre – perhaps even more if the weather has been very hot. Established plants with deep roots can keep going in a spell of drought, but young plants may come under stress.


Water application


Apply water to vegetables, lawns, flower beds and borders and rockeries with a hose and sprinkler. Allow enough time for an adequate amount to be delivered, letting it soak down where it will be effective. Heavy, short bursts are no good – the water just runs off.

When watering larger plants, make a little dyke around them and fill it inside with water. Re-fill it, if the water disappears quickly. Shallow rooting shrubs such as rhododendron often need this attention, even as established plants. Wall shrubs, too are very drought-prone because to the rain-shadowing effects of the wall.