I am glad you put holes in the bottom of the cans. Make sure you use ONLY sterilized potting medium. Do not use bark on the top of the soil. That is not sterilized and causes loss of nitrogen.
Soak the soil and then allow to dry out before watering again. This shallow watering makes absolutely NO SENSE. Perhaps for cactus but not for geraniums. They do tolerate more dryness than other plants that aren't succulent or cactus but if you don't water deeply and then allow the soil to drain and dry out a bit your plant will be very stressed.
You MUST add fertilizer. A balanced fertilizer; Less is Best, More is Death and None is Dumb...grins, my very own little ditty that is important to remember. Fertilizer is NOT plant food. Compost is not fertilizer, a balanced fertilizer. Blood meal is not balanced fertilizer nor is fish emulsion. Never use a fertilizer that is higher in N than in P and K. 14-14-14 is fine, it is equal in numbers. More N in a percentage relative to P and K will promote vegetative growth, few flowers! N should be lower than P and K such as; 5 - 9 -7 to grow more flowers...you have to cut those flowers off! Once an annual is allowed to set seed that plant has done its duty in this life and the plant will die.
By cutting off the flowers you frustrate your plant trying to make seed. The plant grows larger, more focused on producing more flowers to be more successful at producing seed. Seriously...cut the flowers off at the beginning and pretty soon you won't be able to keep up with all the flowers. But you have to be brave...at the beginning of the growing season!
Potting soil, drainage, deep watering then allow to dry out, proper light, a little balanced fertilizer, no non sterilized mulch added, no other 'goodies' or food added. Lift the bottom of the pot off the surface it is sitting on for the best drainage. If you want to put this plant into the direct sun you have to acclimate your plant FIRST. As long as this plant is under cover and has stable temperatures, your plant will thrive. Best in full sunlight but if you did that now you would kill your plant via sunburn.
Cut those flowers off of your plant as soon as you can stomach cutting off the flowers! Your plant will be more vigorous, get larger and grow MORE flowers...