Richard
07-30-2008, 01:30 AM
This is a topic for both organic and inorganic gardeners. Fertigation is the injection of liquid or water-soluble nutrients directly into irrigation lines. There are many naturally occuring compounds and plenty of synthetics as well which fit this purpose.
I need to upgrade the size of my current fertigation system and after looking at prices in the $2000 range decided to research how to make my own. Along the way I discovered some interesting facts which I'll share here.
There are two categories of fertilizer injectors: Proportional and Non-proportional.
Proportional: The same concentration of fertilizer is added to the water until the fertilizer solution is exhausted.
Non-proportional: Water is "bled" into a container, and then some of the mixture is forced back out into the water stream. This is problematic because the more water that is bled in, the weaker the concentration in the container becomes. In fact, it gets weak very rapidly (hey math geeks: it decreases geometrically).
Here's what happens when you try to feed 100 trees 25 gallons of water each with a proportional vs. a non-proportional 15 gallon injection tank. Notice that if the trees are watered non-proportionally in batches or in rows, then most of the concentration goes to the first 8 trees.
http://www.bananas.org/gallery/watermark.php?file=11895 (http://www.bananas.org/gallery/showphoto.php?photo=11895)
Here's some common non-proportional injectors/feeders on the market, made by Scotts / Miracle Gro and EZ-FLO (http://www.ezfloinjection.com/1-1.asp). Note that EZ-FLO claims to be nearly non-proportional in the lowest ratio setting, but in reality, few people if anyone find that setting and water pressure useful.
http://www.bananas.org/gallery/watermark.php?file=11890 http://www.bananas.org/gallery/watermark.php?file=11888 http://www.bananas.org/gallery/watermark.php?file=11889
... and for comparison, here's some proportional units made by Champin, Ortho, and Strong Enterprises (http://fertilizerdispensers.com/services/index.htm):
http://www.bananas.org/gallery/watermark.php?file=11892 http://www.bananas.org/gallery/watermark.php?file=11894 http://www.bananas.org/gallery/watermark.php?file=11893 http://www.bananas.org/gallery/watermark.php?file=11891
I need to upgrade the size of my current fertigation system and after looking at prices in the $2000 range decided to research how to make my own. Along the way I discovered some interesting facts which I'll share here.
There are two categories of fertilizer injectors: Proportional and Non-proportional.
Proportional: The same concentration of fertilizer is added to the water until the fertilizer solution is exhausted.
Non-proportional: Water is "bled" into a container, and then some of the mixture is forced back out into the water stream. This is problematic because the more water that is bled in, the weaker the concentration in the container becomes. In fact, it gets weak very rapidly (hey math geeks: it decreases geometrically).
Here's what happens when you try to feed 100 trees 25 gallons of water each with a proportional vs. a non-proportional 15 gallon injection tank. Notice that if the trees are watered non-proportionally in batches or in rows, then most of the concentration goes to the first 8 trees.
http://www.bananas.org/gallery/watermark.php?file=11895 (http://www.bananas.org/gallery/showphoto.php?photo=11895)
Here's some common non-proportional injectors/feeders on the market, made by Scotts / Miracle Gro and EZ-FLO (http://www.ezfloinjection.com/1-1.asp). Note that EZ-FLO claims to be nearly non-proportional in the lowest ratio setting, but in reality, few people if anyone find that setting and water pressure useful.
http://www.bananas.org/gallery/watermark.php?file=11890 http://www.bananas.org/gallery/watermark.php?file=11888 http://www.bananas.org/gallery/watermark.php?file=11889
... and for comparison, here's some proportional units made by Champin, Ortho, and Strong Enterprises (http://fertilizerdispensers.com/services/index.htm):
http://www.bananas.org/gallery/watermark.php?file=11892 http://www.bananas.org/gallery/watermark.php?file=11894 http://www.bananas.org/gallery/watermark.php?file=11893 http://www.bananas.org/gallery/watermark.php?file=11891