It can be done, but isn't advisable for two reasons. First, the salts in traditional ferts kill organics. Second, the organic colonies take a while to build up and the period between veg and bloom is a high growth time period. I believe your plants would have massive nutrient deficiencies if you tried to make the switch at this point.
I highly recommend making the switch away from chemical fertilizers, though. They are a prime cause of soil desertification and the nitrification of our waterways. Plus, the purchase of synthetic nutrients lines the pockets of companies like Monsanto, Bayer, and DOW. Monsanto is pure evil, and is trying to bully our American farmers into virtual surfs. Bayer and DOW aren't much better. These three companies are also currently lobbying to keep the public from knowing what GMOs are in the food we purchase and what they are feeding the animals that produce our food. Thus far, they have gotten their way. The more I find out about their tactics, the more angry I get. Thru organic methods such as Korean Natural Farming, I can make sure that none of my money goes their way....whether it was the raw materials or the final product purchased.