It's just as easy to fertilize plants with Drip Irrigation as it is to irrigate them with plain water. It's just a matter of connecting a Fertilizer Feeder into the water line ahead of the Irrigation System.
Fill the Feeder with the proper fertilizer, according to the manufacturers instructions, and turn the system on. It's that easy !
Optionally you can use a mechanical timer to Irrigate or Fertilize for a given period of hours (often 1/2 to 3 hours). You turn a knob to wind the spring, with no batteries to worry about. At the end of the time period it shuts off. If your plants need more water, you turn the knob again.
An electronic Timer gives you many more options; like turning the water on and off while you are not home. Some can be programmed to repeat a watering pattern for any or every day of the week, or have different patterns on different days. Maybe you want to water at a later time on Wednesday so the Delivery Man doesn't get irrigated, or is that "irritated" ?
The container holds a given amount of water-soluble fertilizer. It is sold in these packet sizes at an elevated price, because it's easier to dump the packet than to measure it from an economy container. As the water goes through the Feeder, it dissolves some of the granular fertilizer. This ratio is preset by the orifice size. Be sure the container is screwed on tightly, and double-check for leaks.
Some Feeders are made with a dedicated sprinkler head. Be certain the one you buy has Garden Hose Threads (GHT) on both ends, or you will not be able to attach standard fittings to the outlet. These Feeders can be reused, and they can also be attached to mechanical sprinklers to fertilize your lawn.
The small black part beside the Feeder is a Filter Washer with tiny holes that protect the Drippers from clogging with foreign particles. I would not use this system without this inexpensive Filter.
This small device automatically maintains a low working pressure that prevents the friction-fit Drip Irrigation accessories from blowing off at higher water pressures. It normally has GHT on both ends.
1/4" Tubing Adapter:
To go from GHT to standard 1/4" Drip Irrigation accessories you will need an Adapter. I made the brass one on the bottom from a Sweep Nozzle and a piece of copper tubing. It screws onto a garden hose and fits inside the 1/4" tubing. These are now available in plastic from Garden Centers.
The original Tubing Adapter is shown above with a yellow band on the end where 1/2" Supply Tubing is forced into it. The tubing is then punctured to receive many accessories including the Double Barbed Adapter shown below it. The translucent tubing is then slipped over it and the black/blue Dripper shoved into the end. Reversing the Dripper changes the drip speed.
from the staff of Garden Grapevine