Fertilizing Gardenias

Once you have planted your beautiful gardenia shrub and established a consistent watering schedule. Another important step in taking good care of your plants is to fertilize them. Gardenias need extra nutrients using plant food or fertilizer. A regular feeding schedule will produce shiny dark green leaves and loads of creamy flowers. Gardenias love acidic soil conditions, so the type of fertilizer you choose should be one well suited for acid loving plants. These come in a variety of forms, powder, pellet, or even liquid. Make sure to read product labels and gardenia should be listed as one of the plant types the product is designed for. Gardenias need extra iron and copper to thrive and grow and produce flowers.


You also only want to fertilize your plant during the spring and summer months when they are actively growing and blooming. You do not want to feed your plants in the late fall or winter months when they are dormant and do not need the additional boost of nutrients. Feeding during this time could cause over fertilizing and cause your plant to wilt and not thrive. In the spring once you see new green leaves emerge on your shrubs you may start your feeding schedule again. 

How to Fertilize Gardenias 

Gardenias are acid loving plants and a simple pH test can determine if your soil needs some amending. You can purchase soil test strips at most garden centers or send you soil off for a professional test. Check with your local county extension service or master gardener group. An easy method for adding acid to your soil is to mix one tablespoon of white vinegar in a gallon of water and use this once a month to water your plants. This will help maintain an acidic soil pH if your soil needs a boost. Shop for fertilizer products that are designed for acid loving plants like your gardenia shrub. Important nutrients for Gardenias are iron and copper; these should be listed on the product label. These minerals aid in the production of healthy leaves and flowers.

Fertilizers can come in a variety of forms such as powder, pellets, and liquids. Read the information on the product package, as some may need to be diluted with water. You can then apply your fertilizer directly to the soil at the base of your plant. Make sure the root zone is covered. This is the area where the roots are growing. The root zone could be a few feet from the trunk of your shrub. It is important to not over fertilize your plants. If you are not sure it is better to use less fertilizer or skip a month. Gardenias can be a bit sensitive and like too much water that will cause them to wilt and drop their blossoms so will too much rich plant food or fertilizer. 

Best Time To Fertilize Gardenias 

The best time to fertilize your gardenia shrubs is when the plant is actively growing and blooming. Know your growing season and when it starts and ends. This is usually calculated from the last hard frost of the winter to the first frost date in the fall. During this period is when you will want to apply your fertilizer product. During the spring and summer growing season. This will keep them healthy and produce beautiful flowers. You may feed them a little in the fall but it is not necessary as they are preparing for winter and their dormant season. During the winter months the plants do not grow so there is not a need for extra food or nutrients to be added to the soil.

Fertilize your plants monthly to avoid over fertilizing or feeding. A regular feeding schedule with plant food designed for acid loving plants is best. This is true for gardenias that are planted in containers as well. Always read the fertilizer product instructions on the package and it is better to use less or dilute with water than to over fertilize. If you are not sure about how much to use, using less is always better than too much. It is also important to water your plants first before applying plant food or fertilizer products. This helps them not only absorb the nutrients better but also avoids shocking a thirsty plant and burning a delicate root system. It is important for young plants or newly transplanted shrubs to not over fertilize. Let them get established for a few weeks before giving them any plant food. 

Best Fertilizer For Gardenias 

For beautiful blooms and healthy leaves on your gardenia plant you will want to use a high quality plant fertilizer. Choose one that is designed for flowering acid loving plants and shrubs. Look for products that feed your plants at the root level and can be applied monthly. You may also choose a slow release product that may last you the whole growing season or only needs to be applied every other month.

If your gardenia is planted in a container you will also want to fertilize your container. When planting new plants you can choose potting soil mixes that already contain fertilizer and are also designed for acid loving plants. The type of fertilizer you choose is a matter of personal and yard choice. It is often smart to choose a product that will do double or triple duty considering the other plants and shrubs you also have growing in your yard. This will save you both time and money. 

Gardenia Fertilizing Tips

  • Look for products designed for gardenias and other acid loving plants.
  • Apply fertilizer products only during Active growing times. This is the spring and summer months. 
  • Do not fertilize in the late fall and winter months 
  • Apply fertilizer and plant food to the soil at the base of your plant and over the root zone.
  • Look for fertilizer products that have extra iron and copper, these two minerals benefit gardenias plants. 
  • It is better to underfeed your gardenia plants than to give them too much fertilizer or plant food. 
  • Water your shrubs and plants first before feeding.

Always wear protective gloves and a facemask when handling chemical fertilizers.

Read and closely follow all directions and storage guidelines that are on the fertilizer product label.

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Author Janice Cox - Published 10-07-2021