Tuesday, April 27, 2010

Getting the Most From Fertilizer

I have been looking for a way to band fertilizer in my vegetable beds. I only have about a quarter acre to play on so I work with smaller tools as a rule. Many organic materials are very dusty powders that are difficult to apply, especially if there is any kind of weather going on. Banding means to put a line of fertilizer within a few inches of the roots. Fertigating, a term coined by Steve Solomon-“Water Wise Vegetables”, helps conserve water and fertilizer by providing both where they are most needed.

This also makes it economically viable to add mycorrhizae to the mix in enough concentrations to do some good without spending a lot of money. The rationale is to provide good nutrition to the soil where the plants can get it. It isn’t helpful to put material where it is not usable because of a variety of field limitations that put the material out of reach of the plants. If the plants can’t get to the fertilizer then it either gets locked up in the soil or leached away by rain. Banding should help control fertilizer costs while maximizing your return on your fertilizer investment by accurately putting the fertilizer where it would do the most good. I looked at converting a regular garden drop spreader by masking off areas that I didn’t want to drop material with masking or duct tape but I wasn’t confident that I would get a good even drop because those units are primarily designed to work with material that is more pelletized than powder.

I had a epiphany one day where I had seen the device I was looking for. If you have ever been to a baseball or football game you may have seen someone freshening up the base lines with a “dry line marker”. After doing a bit of research it looks like this may meet all of my fertilizer banding needs. The first one I found was a Stackhouse 25 pound marker for $85 plus shipping that puts down a 2 inch wide chalk line but has no other calibration that I could see. The next unit I looked at, the Alumagoal, for $116.34 with free shipping has a way to calibrate the width of the drop from “Off” to 4 inches wide so a fairly reasonable method of calibrating the tool to drop the intended amount although you might need to make more than one pass to get the right amount down.

To calibrate a tool like this, or any drop spreader or seed drill for that matter, spread a tarp out on level ground and mark off a measured distance. Fill the hopper and set it to a medium drop rate and make 2-4 passes back and forth on the tarp. Make separate passes by not going over the same spot twice so you can see if your tool has any obvious variations in the drop rate on any of the passes. If it looks like you are getting way too much or not enough material adjust the tool and repeat after cleaning up the material that has already been dropped and start over. The more passes you do and the more material you drop the more accurate your calibration will be.

You need to weigh the material and divide the weight by the amount of ground the tool would cover. You should also pay attention to any variations related to the evenness of the drop. For instance, does speed make a difference in how much material per square foot is dropped? Does the applicator drop less at the beginning or end of a pass? Do coarser materials or materials with larger granules drop at a slower or faster rate than dusts? You should calibrate the tool for each blend of fertilizer you use until you have a good handle on how it performs. If you want to cover the hole width of a row then I would look at something like Scotts AccuGreen® 3000 Drop Spreader which is available in most hardware stores.

Banding may not be a good method for putting down all types of fertilizer. If you have a soil test that says you should put down a certain amount of lime to raise the pH then I would spread that evenly over the entire growing area. Other fertilizers, especially ones supplying nitrogen I would get as close where the plants are going to be as possible. A tool like this might not work well in beds that have soft, wet, or very uneven soil.
Baseball Field Dry Line Marker - 25 lbs Capacity
Alumagoal All-Steel Dry Line Marker

Contact your U. S. Representative and ask that they become a cosponsor of and support H.R. 4971: Greening Food Deserts Act.
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