Position your container near the garden bed you want to fertilize. You'll need to set it up on a stand or rocks in order for siphoning to work, and this is much easier done empty than filled.
Make a mix of water and fertilizer in a large, airtight container. The size of the container depends on how often you want to revisit and replenish the fertilizer mixture. How strong the nutrient levels are will depend on the type of plant and how well-drained the soil is. As a general rule, moisture-loving plants should have a more diluted nutrient level and higher flow, whereas plants that need drier conditions should have higher concentrations of nutrients but a much lower flow.
Drill a hole in the top of the container just wide enough to slide your hose through. The hose should be inserted so that one end is able to reach the bottom of the container. Seal around the hole with duct tape in order to keep out egg-laying insects.
Attach an adjustable flow regulator to the other end of the hose. This will give you the ability to make adjustments based on the specific needs of your plants. If you notice that the soil is becoming soggy you'll be able to reduce the amount of water and nutrients it receives.
Start the siphoning process whenever you and your garden beds are ready. Siphoning is a simple physical process whereby water naturally maintains its own level. In order to start the flow, you'll need to position the end of the hose that is not inside the container lower than the surface of the liquid. Suck on the hose until the liquid is flowing, and then adjust your regulator to the desired flow. At this point, if you want to use a trickle system in the garden to distribute the nutrients more evenly, you should attach the hose to the system. The flow of nutrients will continue until the water level reaches that of the hose, or until the container is empty. In order to continue until empty you'll need to make sure the container is set high enough that the bottom of the container is higher than the final outlet where the nutrients emerge.