The daisy (Compositae or Asteraceae) family of plants contains more than 20,000 species, and many different genuses are known as African daisies. This includes Osteospermum, Dimorphotheca, Arctotis and others. The various plants known as African daisies may differ in color and name, but all of them require regular watering to survive.
How Often to Water
How often you need to water African daisies depends on several factors, including the stage of growth of the plant. Newly planted African daisy seeds must remain moist for the first week to 10 days to encourage germination, which requires 1/4 inch of water daily. African daisies transplanted into the landscape need watering every two or three days for the first 14 days after planting, twice weekly for the next 14 days and then weekly watering thereafter.
How Much Water
African daisies should be watered when the top 2 to 4 inches of soil is dry. Use a hand trowel to dig near the plants to this depth. However, to thoroughly water the plants, the soil around them should be moist to a depth of at least 6 inches. A common rule of thumb for watering most plants is to supply between 1 to 2 inches of water weekly. This includes supplemental watering as well as rainfall amounts.
When to Water
The best time to water African daisies is early in the morning while the temperatures are low and winds are less likely, since the absence of these decreases water evaporation. If you are unable to water in the morning, the next best time is in late afternoon. Many gardeners install various types of sprinklers or soaker hoses to use for watering African daisies, which is a sufficient method of watering in place of hand watering.
Ways to Maintain Moisture
Other factors that affect how often and how much water African daisies need is the soil type and temperature. Enriching the soil in the planting area designated for the flower -- with several inches of organic matter, like compost, peat moss and manure before planting the African daisy -- will improve the soil's ability to hold water. This is especially important for dry, sandy soils. Adding a thick layer of mulch around the planted African daisies will lower the soil temperatures and help retain moisture.