I'm trying to find a method to allow distributing nutrients to my 200 lavender plants by way of my drip irrigation system. Somewhere I had seen a distribution box to regulate such a process, but it was designed for very small-scale gardening. —Jim W.

Based on your question, it seems like you have an existing drip irrigation system already set up to water your 200 lavender plants. As long as this system is fully functional and properly sized, you should be able to add some kind of fertilizer injector fairly easily to be able to give your plants nutrients along with their water.

I am not familiar with a “distribution box” per se, but what I think you might be talking about is an inline fertilizer injector. These do come in all sizes and levels of sophistication. If you do an online search for these, you might find something similar to what you had seen before. For small to medium scale farming and growing, you would probably want to invest in something a little more substantial, such as a Dosatron (or comparable other manufacturer) injector. If you aren’t ready to invest in one of those yet, a simpler, cheaper, yet still effective type of injector would be a Mazzei Venturi type of injector which has fewer moving parts than a Dosatron.

Regardless which brand of injector you decide to use to deliver nutrients to your lavender plants, make sure that you have a filter to prevent oversized particles of nutrients from getting through and clogging your emitters. You will also need to make sure that you have a backflow preventer so that your nutrient mix doesn’t wind up getting into your main water supply. If your system is already working fine and delivering water at a sufficient volume, then you probably don’t need to change the existing lines and emitters to accommodate the addition of your nutrient solution.

Once you are set up with the injector of your choice and are ready to start feeding your plants, use less than the recommended rate of fertilizer. It is good to start out at about half the rate listed on the packaging. This is to make sure that your injector does not make your irrigation water too rich with nutrients, until you have a good handle on the distribution rates of your system. A good check is to start with some food coloring. This can help you to easily check if you are getting good flow of nutrients all the way down the length of your lines.

If you find that your system does not deliver all the way to the end, consider adjusting pressure and flow rates. Don’t guess at this though; use equipment to measure. Water meters and pressure gauges can be installed anywhere along the run. They can tell you exactly where the weak points are and where you need to make adjustments.

I hope this helps! The world is a slightly nicer place with lavender in it!