Um. Hmm. No easy way to reply to this. You have NO budget? Because $20 bucks might save your plants.
It depends on the environmental conditions you're growing under. I didn't find your previous threads, so I claim ignorance. But if the heat produced on the surface of the plants is around room temperature (65-75 degrees f), you should be fine. -Saturate- the soil medium with water. To the point that the soil can't absorb anymore, and there is about 1/16th [preferrably] - 1/8th of an inch above the soil. This might hurt your plant for a day or so, but it shouldn't cause root rot or anything of the sort if you're growing in decent conditions (adequate container size, etc). This should keep the plant happy throughout the duration of your trip, but do it a day beforehand to see how it reacts. I've had plants with which I've soaked the soil to 1/8th of an inch above the soil line, and it pulled through. With tremendous results (since the water contained a bit of FoxFarm Grow Big).
But your best bet is to buy a water pump with a large plastic tube or length of garden hose (with holes poked along it every so often), or an air pump creatively engineered to deliver water. It can be done, I promise you. And this will run you about $20, is all. It depends on what you're capable of doing, and the means you have.
~Ethno