Answer: I water my houseplants by up-ending water bottles and sinking them into the soil up to their shoulders. One pint does a 2-gallon container for about a week. Water everything well first and then set the water bottles in the soil. As the soil dries out the water trickles out of the bottle and into the soil. You can probably use the same method, depending upon the sizes of your planters and how thirsty your plants might be. You could use liter sized bottles or even half gallon or gallon milk containers rinsed well and then filled with fresh water. Try it before you leave, though, so you'll know how long it takes for the containers to use up all the water. Have a great vacation!
Q&A Library Searching Tips