If you are looking for a steady watering system for your plants so that they are well-irrigated but not over wet, then you need a drip irrigation system. You can make one using nothing more than a used soda bottle and some common tools. This system is not only cheap and simple- it's also made from 100% recycled materials.
2-liter soda bottle
1/8 inch or 3/32 inch drill bit
To make your irrigation system, cut off the base of the soda bottle with a knife and invert the bottle so that top part of the bottle is now at the bottom and the original base is now the open top.
Using a 1/8 inch 3/32 inch drill bit, drill two holes in the cap. Put water in the bottle through the open top end and fill the bottle to the halfway point. Water will drip down through these holes. Measure how long it takes to empty the bottle. The bottle should get emptied in about 20 minutes. But if it takes much longer, drill another hole in the cap.
Excavate a hole in the soil 4 to 6 inches away from the plant that you need to water. Place the bottle in the hole at an angle of 30 - 45 degrees. The hole should be deep enough so that cap with the holes is completely under the soil and the open end is on top, outside the soil. While digging the hole in the soil, be careful not to cause any damage to the plant roots. After you have placed the bottle in the soil firmly and properly, place some dirt around the bottle to prop it up.
This simple system is superb for tomatoes, eggplants, squash and peppers. If you want to apply fertilizers solutions or compost tea to your plant, use a filter to prevent the holes from getting blocked by the solid particles of the fertilizer. You may use a window screen or filter floss as a filter. Fill the bottle with water and add the fertilizer you wish to add.
Use the bottom part of the original soda bottle which you had cut off to cover your irrigation system. This will prevent dirt from entering the water and keep it clean and, at the same time, will minimize evaporation of the water in the system.
This system is easy to set up, and you can probably make it without having to buy too many things. It is also one of the eco-friendliest, water saving irrigation systems you could possibly install.