Ivy Geranium ( Pelargonium peltatum (L.) L’Hér.) Plant Growth and Flowering as Affected by Mineral or Biofertilizer with or without Compost Amendment

Sustainable agriculture aims to eliminate the excessive usage of chemical fertilizers and can be crucial for soil fertility. A factorial pot experiment in a randomized complete block design was carried out in King Khaled International Airport Nursery, Riyadh, Saudi Arabia, during 2019/2020, to evaluate the role of a biofertilizer (i.e., Bio-Fert, nitrogen-fixing microorganisms; Biot-Phos, phosphorus-released microorganism; and Bio-Potas, potassium-released microorganisms, either alone or in combinations) and slow-release compound chemical fertilizer (Osmocote), with or without compost, on Pelargonium peltatum plant growth, flowering, chlorophyll level, and ion percentage. Soil amendment with compost in general significantly increased plant growth and flowering attributes as well as chlorophyll level, nitrogen (N), phosphorous (P), and potassium (K) percentage over garden soil (without compost). All growth and flowering traits as well as ion percentage and chlorophyll level were significantly increased by biofertilizer treatments either alone or in combinations. The supreme treatment was the triple interaction over single or double interactions or untreated plants. Osmocote application increases chlorophyll levels, ions, flowering, and vegetative growth relative to untreated plants. Additionally, the data also revealed that all interactions between either osmocote or biofertilizers with compost significantly increased all studied attributes over each treatment alone or untreated control plants. Accordingly, it is recommended to add compost to the soil along with a triple mixture of biofertilizers for obtaining high plant growth and flowering attributes along with soil fertility.