Any hydro shops in your vicinity? Not knowing what's available in your area, you'll have to do some legwork, or make some phone calls. Most get a 2 or 3 part system from the same manufacturer. (a bottle of grow nutes, one of micronutes, and the bloom nutes) Fox Farms, Botanicare, General Hydroponics, Canna...are but a few. Make sure to get the nutes for soil, not hydro if applicable. I use the Fox Farms trio, but get what you can find. I know Botanicare and Fox Farms have schedules available online for ease of use, and clarity. Great for newbies.

Do you already have transplant pots for when they need 'em?

Regardless of where you get your water, you'll want to know the ph and adjust accordingly if need be...Pronto.