Jobe's 50 Pack 10-10-4 Flowering Plant Spike Bonus Pack. This slow-release fertilizer provides all the nutrients your flowering plants need to thrive. Simply insert the spikes into the soil around your plants and water them in. The fertilizer will release nutrients over time, feeding your plants for up to 8 weeks. The 10-10-4 formula is ideal for flowering plants, as it provides the right balance of nitrogen, phosphorus, and potassium to promote healthy growth and vibrant blooms.