Going on vacation is a great way to relax, so you don't want to be worrying about your plants dying while you're gone. You don't have to stay home just because you have an indoor garden to take care of. There a lot of simple solutions to watering your plants while you're gone.
Ask a Friend
OK, it may sound obvious, but asking someone you trust to swing by your house a couple of times while you're away might be the easiest thing to do. This solution is best if you just have a few houseplants that need to be watered a couple times while you're gone. Having someone stop by the house may also be necessary for plants that have complicated care instructions, such as peace lilies. But make sure this person is someone responsible and trustworthy. It's always good to have someone stop by your home while you're gone anyway to make sure your home is in order and possibly to pick up your newspapers and mail.
You can find many automatic watering systems for house plants. You've probably seen the infomercial for the glass bulb that looks like a turkey baster. You fill the glass bulb with water and stick the open end in the dirt. The air pressure inside the bulb controls the amount of water that is released to your plants. There are also automatic watering pots with hoses attached. You fill the watering pot with water and extend the hose to your plants. The watering device then gives your plants a certain amount of water a day. These devices can be expensive though.
Try building a homemade system for watering your plants. Place a dish rack upside down in your bathtub. Put your plants on top of the dish rack without saucers under them. Take shoelaces and stick one in the hole in the bottom of each pot, letting the laces hang down into the tub. Fill the tub with a few inches of water, and the shoelace will act as a long root extension, pulling water up to the plant. This works best if your bathroom gets plenty of natural light.
Hook a sprinkler or soaker hose to an automatic timer that will turn the water on and off. The best time to water outdoor plants is before the sun comes up in the morning.