Hello there! Novice gardener here! I have a rather large balcony that has some hanging planters already attached to the balcony. I planted some things last summer and had a pretty good rate of success. However, when it rains the rain water runs off the roof and pours into some of the planters Last summer I just kept a bag of soil and kept refilling after a heavy rain. My neighbor suggested putting a/c filters over the soil, but that just seems too ugly. Any suggestions. I recently planted some wildflower seeds and there coming up nicely except where the downpours hit them. I live in New Orleans and we go through some rainy periods.
I had a problem like that and solved it by having new gutters installed. I have the impression, however, that your place is an apartment, so it's not likely you could do what I did.
I guess if I were in your situation, I would, in fact, keep a close eye on the weather. If it looks like there's going to be a storm, take the plants off their hooks and move them back under the balcony roof.
You might ask the building supervisor if there was a way to repair the guttering over your balcony, or correct the overflowing water. The owner or supervisor might be interested, since the overflowing water might be causing damage to the building. Just a suggestion.
If you own the property, I highly recommend that you get the problem fixed properly. Overflowing gutters can allow rot to develop in the wood behind the gutters.
Novice gardener here! I have a rather large balcony that has some hanging planters already attached to the balcony. I planted some things last summer and had a pretty good rate of success. However, when it rains the rain water runs off the roof and pours into some of the planters 
Last summer I just kept a bag of soil and kept refilling after a heavy rain. My neighbor suggested putting a/c filters over the soil, but that just seems too ugly. Any suggestions. I recently planted some wildflower seeds and there coming up nicely except where the downpours hit them. I live in New Orleans and we go through some rainy periods.