How Often to Water Geraniums in California

Questions people ask

How much water do geraniums need in summer?

In July, an established planting needs roughly this many gallons per square foot: 0.64 in the North-Central Coastal zone, 1.07 in the Central Valley zone, 1.98 in the South Coastal zone, 2.51 in the South Inland zone. Figures are computed from the WUCOLS rating for Pelargonium x hortorum and cvs. and each zone's reference evapotranspiration, and they are plant needs before irrigation system losses.

Does watering for geraniums change across California?

Yes. WUCOLS rates geraniums separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Can you overwater geraniums?

Yes, and it kills far more geraniums than drought does. Constantly wet soil rots the roots and the base of the stems, a problem growers call blackleg: stems turn dark and mushy while the leaves yellow and drop. Let the soil dry a couple of inches down before you water again.

Why are my geranium leaves turning yellow or red?

Yellow lower leaves usually mean too much water or soil that never dries out. Red-tinged leaves are a stress blush, most often from cold nights or a plant kept too dry. Check the soil before reacting: if it is damp, hold off; if it is dry well below the surface, water deeply.

What are the corky bumps on the underside of the leaves?

That is oedema, and it appears when roots take up water faster than the leaves can use it. Cells swell and burst, leaving rough tan or brown patches, most often in cool damp spells and on overwatered plants. Let the soil dry more between waterings and it stops spreading; scarred leaves never heal, so pick them off if they bother you.

How should I water newly planted geraniums?

Keep the root ball lightly moist through the first summer while roots grow into the surrounding soil. After that, shift to deeper, less frequent watering and let the surface dry between drinks. Established plants are far tougher than new ones and would rather be slightly dry than steadily wet.

Is drip irrigation good for geraniums?

Drip suits them well. It wets the root zone without splashing the leaves and flowers, which cuts down on rust and gray mold, two diseases that thrive on wet geranium foliage. Run it long enough to soak the root zone, then let the soil surface dry before the next cycle.

Should I water geraniums in winter in California?

Rarely in the ground: growth slows in the cool months and winter rain usually covers what the plant uses, so water only during long dry, warm spells. Keep an eye on containers under eaves and covered patios, since rain never reaches them, though even those need much less than in summer. Ease off further when frost threatens, because soft, well-watered growth is the first to burn.