The hydroponic nutrient is somewhat like miracle grow. We bought it online, as a two part mix, for about $25. We only used less than half for 2 full seasons - now this is our third season. It just has to be something that's water soluble. If you want the real specifics, I can get them from my husband, cause I don't know the name of it or anything. :)
The cantalope is an experiment for this year. Not sure how it's going to work. I do wonder if the vine will be strong enough to hold the fruit up in the air as it is. Well see.
You should try the thornless variety of black berries. They're slightly expensive, but will divide up and turn into MANY plants in no time. We bought only a few little twigs a couple years ago, and it's turned into about 20 large bushes now. The berries are very big and juicy too. We also bought raspberries (not thornless). One difference between the two, is that the blackberries make new plants with cuttings (or if a long branch touches the ground, it'll grow from that). But the raspberries grow like the wild blackberries - by the root system, starting new plants one to two feet from the parent plant. I sort of DON'T like for them to grow by the roots, because you can't exactly control where they go. So the raspberries don't stay in the bed where we planted them, but want to spread out. The thornless blackberries are easier to control.