The constant watering will flush out the fertilizer, fairly quickly. If the soil is truly organic, it shouldn't have 20-20-20 in it, since that is not a ratio often found in organic form, so there may be slow release granules in the mix that will take 3-6 months to be used up. I think people over react to the idea of fertilizer. Whether it's manure (organic) or granules (synthetic), it's all still naturally occurring elements and unless ingested in large amount will do no harm. Make sure the plant has better than adequate light, as the water and fertilizer will make it want to grow and so so light will mean that growth will be weak and elongated, and you want it to be compact and sturdy.