Another Balcony

My north-facing balcony gets no direct sun.  So here is what I came up with...
Just a simple combination of mother-in-law's tongue (Sansevieria trifasciata) and southern maidenhair fern (Adiantum capillus-veneris).  I covered the soil with moss but it gets dry fast - this summer is really hot.  I water it periodically, about once a week - how do I make sure I do not over-water it? I do not let water stand in the saucer for more than few hours.  Oh and I have no idea whether these plants are compatible - they are sold in the same section of a big box store so I presume their light requirements are similar (low).  No idea about water requirements.  I think this is the most esthetically pleasing combination of plants I have.

Here is my attempt to propagate Sansevieria. Two leaf cuttings (about 3 inches in length) stuck in growth media enclosed in a zip-lock bag to preserve moisture.

Finally here is a plant I own for at least 3 years.  After a year of neglect (I do not think I watered it at all!) I replanted it (it was totally root-bound) and cut dried leaves completely.  It recovered!  I think this is a sago palm Cycas revoluta. I have no idea how it survived outside all this time.  My plan is to keep it outside in a corner which gets some morning sun.  The undergrowth you can see - these are some seeds sprouting - my 4yo son loves experiments and I just can't say no.  What was that?  Onion?