Answer: I wouldn't be to quick in transplanting your tiny cacti. The roots will be small and if you set them in a huge container (for their size), the potting media can get sour before the roots will grow large enough to explore the soil. I'd keep them in their own pots until you see roots escaping from the drainage holes. It isn't necessary to feed cacti or succulents. They grow well in lean soil. If you feel the need to feed them, use a half strength dilution of a water soluable houseplant fertilizer. That equates to one tablespoon of fertilizer dissolved into one gallon of water. Since you only use a few tablespoons of water per week, and if you fed once a month, this solution will last months if not years! I'm not sure it's worth the expense!
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