Fertilizing Asters

Asters are not heavy feeders and do not require fertilizer in fertile garden soil. Usually, a light application of compost in spring is sufficient for supporting continuous growth. In nutrient-poor soils, a balanced flower fertilizer can be applied monthly beginning in spring and until the flowers begin to open. Newly planted asters typically require no supplemental feeding as they come from the nursery with plenty of nutrients in their pots for the first year. 


How to Fertilize Asters

Apply a top-dressing of organic compost in early spring to start the growing season strong. Alternatively, a balanced, granular fertilizer such as a 5-10-5 or 10-10-10 can be applied according to the manufacturer's directions around the base of the plant. Avoid applying any type of fertilizer when temperatures may go above 80 degrees Fahrenheit for any length of time as this may burn the plant's roots and leaves.


Best Time To Fertilize Asters

Fertilize with compost or a slow-release feed in early spring when new growth is emerging. This is the time when perennials are putting on growth quickly and benefit from extra nutrients in the soil. It is best to fertilize in cooler weather and preferably before it rains. 

Best Fertilizer For Asters

Granular or time-released fertilizers are better than liquid types and are less likely to burn the plant. Liquid Miracle Gro can cause a build-up of salts in the soil and damage the plant's roots, so use it at half strength sparingly.

Aster Fertilizing Tips

  • Apply a ring of compost in early spring to support growth and soil health.
  • In poor soil, apply a granular fertilizer monthly beginning in spring and stop when flower buds appear.
  • Scatter fertilizer around the base of the plant and scratch into the soil surface.
  • Water well after each application.
  • Avoid applying any type of fertilizer on days when temperatures may exceed 80 degrees for an extended period of time.


-Always wear protective gloves and a face mask when handling chemical fertilizers.   
-Closely follow all directions and storage guidelines that are on the fertilizer label.


"Garden Asters." University of Massachusetts Amherst Extension. ag.umass.edu

"Plant of the Month – Fall Aster." Dallas County Master Gardeners Association. dallascountymastergardeners.org

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Author Chris Link - Published 08-02-2022