How do I keep a garden alive in a drought?

Prioritising which plants get water, watering in ways that actually reach roots, and the mulching that halves the need.

Difficulty: beginner
Time: 45 min
Read: 2 min

Short answer

Water fewer plants more deeply rather than everything lightly. Prioritise new plantings, pots and food crops; established shrubs, trees and lawns can look after themselves. Water at the base in the evening or early morning, and mulch afterwards.

In a dry spell most water is wasted through evaporation or by being spread too thinly to reach roots. A deep soak of the plants that need it beats a daily sprinkle over everything, and it also encourages deeper rooting.

What you'll need

Watering can
Mulch (optional)
Water butt (optional)
Old plant pots or bottles (optional)

Step by step

Decide what actually needs water and what does not.Priority: pots, anything planted this year, and food crops. Established shrubs and trees have deep roots. Lawns go brown and recover — they are not dying.
Water deeply and less often.One thorough soak every few days beats daily sprinkling. Shallow watering keeps roots near the surface, where they suffer most.
Water at the base, at soil level.Overhead watering mostly evaporates and wets foliage. Aim at the soil and let it sink in.
Water in the evening or early morning.Midday watering loses a large share to evaporation before it reaches the roots.
Sink a pot or cut bottle beside thirsty plants.Fill that instead of the surface. The water goes straight to depth rather than running off dry crusted soil.
Mulch immediately after watering.It roughly halves evaporation from the soil surface. Applying it to already-damp soil is essential.
Move pots into shade and group them together.Pots dry out fastest of anything. Grouping raises humidity between them and shade reduces demand substantially.
Collect and reuse water.Water butts, washing-up water — cooled and without harsh detergent — and bath water are all usable on ornamentals.

Tips

A brown lawn is dormant, not dead. It greens up within two weeks of rain, and watering it is the least valuable use of scarce water.
Weeds compete directly for water. Weeding during a drought is worth more than usual.
Delay planting anything new until conditions improve. New plants need constant watering to establish, which is exactly what a drought prevents.

Common mistakes

Watering a little every day — It only wets the top centimetre, keeps roots shallow, and mostly evaporates. Deep, infrequent watering is far more effective.
Watering in the middle of the day — A large proportion evaporates before reaching the roots.
Prioritising the lawn — It is the plant most able to survive drought unaided. Pots and new plantings genuinely cannot.

Questions people ask

Should I water my lawn in a drought?

Generally not. Grass goes dormant and browns, then recovers within a couple of weeks of rain. That water is far better spent on pots, new plants and food crops.

When is the best time to water plants?

Early morning or evening, at the base of the plant. Midday watering loses much of it to evaporation and can scorch wet foliage.