How long is premixed nutrients good for ?

I mixed 1 gallon of purified water with 1/2 strength of General Organics Go Box for Veg stage. I have a soil grow set up, just one plant. My question is, how long is my bottle of nutes good for ? I don't want to put an air stone in a gallon bottle (seems a little over the top for a gallon of water) and If I need to throw away the premix, then does anyone have a recipe for smaller amounts of water/nute ratio ?

How much of the nutrients did you use??

Not much at all, my plant is about to hit 2 weeks from germination so she isn't drinking a lot just yet

If the concentration of solution isn't high (as you said) it will probably be good for long - just remember to shake it well / stir it before use.
If you notice some salt on the bottom (after some time) the solution isn't probably good anymore...

If you aerate it, it'll last longer, especially being organic based. Don't need an airstone. Every day, open it to let in fresh air, cap it, and shake it. Keep it cool and I'd say it'll be good for a couple weeks. I kept a jug of fish fert and water around for close to that a few times, same situation, young plants weren't using it.