How often to water geraniums in California

In July, established geraniums in loam need a deep watering about every 14 days in the Central Valley, about every 7 days on the south coast and about every 6 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

In July in the Central Valley, established geraniums need about 0.1 gallons a day for a plant 2 feet across and about 0.4 gallons a day for a plant 4 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

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.

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.

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.

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.

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.

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.

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.