Miracle Gro is good for gardenias.
Feed the gardenias with Miracle-Gro plant food.
Miracle-Gro Water Soluble Azalea, Camellia, Rhododendron Plant Food is a special plant food designed for acid-loving plants like azaleas, rhododendrons, camellias, dogwoods, magnolias, gardenias, orchids and all evergreens. It is rich in iron and other essential nutrients.
Good plant foods and fertilizers for gardenias include.
Miracle-Gro Miracid. N-P-K Ratio: 30-10-10.
Nelson Acid Loving Plant Food. N-P-K Ratio: 9-13-11.
Jobe's Spikes. N-P-K Ratio: 9-8-7.
Gardenia Liquid Plant Food. N-P-K Ratio: 3-1-2.
Dr. Earth Organic Fertilizer.
Gardenias like soil that is rich in nutrients.
Add plenty of organic matter to the soil such as peat moss or manure to enhance the growth of your plant.
Gardenias perform best in day temperatures of 65-70°F (18-21°C) and night temperatures of 60-65°F (15-18°C).
The most likely reason for yellow leaves on gardenias is low iron.
Gardenias need acidic soil, which means soil with a pH between 5.0 and 6.5.
This pH range makes iron in the soil available to gardenias.
If the pH of your soil is outside those numbers, you can adjust it by adding an acidic fertilizer.