The Coin Garden for Metal Detecting

The Test Garden for Metal Detecting  (click for larger version to print)

Metal detecting takes practice and patience – and one of the most important things you need to do is learn what sounds your metal detector makes for different types of metals in the soil.  This recommended approach would be appropriate for most medium to high end detectors.

Nature is variable and metal detectors are not perfect.  They may occasionally say that a pull tab is a coin, and visa versa.  But statistically speaking, learning your “tones” will lead you to dig better targets, more consistently while leaving the junk in the ground.

I’d like to introduce one of the mainstay methods for learning a metal detector in the turf – The Test Garden.  It takes a couple hours to set up but it can give you a consistent “classroom” for listening and learning your machine.

What a Metal Detecting Test Garden Can Teach You

  • The distinctive double-grunt of nails and fence wire.
  • The crisp, clear squeak of silver.
  • The crisp high-tone sound of copper.
  • The low, clean tone of gold and nickels
  • The scratchy sound of rusted pop tops
  • How similar gold and pull tabs sound.
  • How your detector may mistake a folded pull tab for a coin.
  • The different signals for different types of pennies.
  • How to pinpoint the target using the metal detector’s pinpoint mode.
  • How to determine depth of a target.
  • How differently your detector sounds on targets on the surface versus 6″ down.

Metal Detecting Test Garden Supplies 

  • your metal detector and (ideally) your pinpointer
  • headphones
  • a digging tool
  • An area of turf around 20′ x 20′ ideally with as few roots (tree or bush) as possible.  There should not be any pet containment fences nearby, and you should try not to put it directly under powerlines.   Also consider where your Cable TV, heating oil, phone lines, etc. are routed.  You don’t want to cut them making your garden!
  • A very small package of white or yellow plastic golf tees (bigger, longer ones if possible) – Wal Mart has these for just a couple of dollars.
  • A fine tip sharpie
  • A small can of grass seed (optional)
  • 11 “targets”:    (you can do this with only a few items, but this is for a thorough garden)
    • 1 Silver dime (pre-1965)
    • 1 Silver quarter (pre-1965)
    • 1 Nickel
    • 1 indian head penny (1859-1909)  (88-95% copper)
    • 1 modern, zinc penny (1990+)
    • Pop top from a beer bottle (Ideally a rusty one.)
    • 2 pull tabs  (one folded over into a coin-shape, and one spread out lengthwise)
    • A small iron nail and a large iron nail (ideally rusty)

Everyone can benefit from a test garden!

Everyone can benefit from a test garden!

Steps to Create your Test Garden:

  1. Choose a space, ideally not too close to roots or rocks.
  2. Make SURE there are no electric fences, dog containment fences or other noisy transformers nearby.  Your machine should remain quiet held waist-high even with the sensitivity pretty high.
  3. Mark the corners of your test garden somehow.  You just want to be able to find it year to year.
  4. Put your metal detector in “all metal” mode and completely clear the area of all targets (dig everything, however faint!) so that your garden starts clean.  Use your pinpointer everywhere.  CLEAR THAT SOIL….. are you progressing to #4?   Did you clear the soil?   If not, get back to #3.  Everything will be ruined if there is still stuff in there.
  5. Divide the space into a rough grid, leaving distance between “spots” and the edge of the garden (see illustration)
  6. Sketch your empty metal detecting test garden on paper.
  7. Dig a 6″-7″ deep hole in each spot – neatly piling the dirt next to the hole.
  8. Assign a hole number to each spot and add that number to the top of the golf tee and your paper sketch.
  9. Get your bag-o-targets and put one them flat in the bottom of each hole.
  10. Fill the hole back in.
  11. Insert the appropriate, numbered golf tee into the center of spot – low enough to be clear of lawnmower but directly over the target.

You now have a “test” garden, with a variety of targets buried at a typical 6″ depth, and the notes to help you remember what is where.

Using your Test Garden for Metal Detecting

  1. Turn on and put your metal detector in coin mode, or choose settings as recommended for a beginner from the owner’s manual or online sources.
  2. Spend time on each target, noting how differently they sound.  Some lower-end detectors will have less sophistication here and you’ll need to rely more on the VDI number on the screen since all beeps sound alike.
  3. A Metal Detecting Test Garden will let you learn the difference between a fatty and a new indian!Pay attention to:
    1. The frequency of the tone – high, med or low
    2. The “crispness” of the tone – is it “tight” or “sloppy”
    3. The differences between each type of target.
    4. The VDI number on your display (if applicable.)

When to Go Back to Your Metal Detecting Test Garden

  1. Anytime you’re trying new settings (avoid too many changes.)
  2. When you get a new metal detector.
  3. When you change brands
  4. The start of each season.

Troubleshooting your Metal Detecting Test Garden

I can’t hear any targets or I can only hear the larger targets
Check that your detector is working for items on the surface.  If so, you may have your sensitivity too low.  Turn it up until the detector has “chatter” and then turn it down until it’s gone.

I can hear the silver coins but not the nickel
You probably have a discriminator setting that filters out low conductivity items.   Try putting your metal detector in “all metal” or “zero descrim” mode to make sure it can hear the targets.

Everything sounds the same – the nails, nickel and coins are identical.
Your machine simply may not make different tones for different targets – typical of lower end machines.  You’ll have to depend on the display more.
You may accidentally have your metal detector in pinpoint mode.  Turn off pinpoint mode and try again.  This is VERY common mistake.
Your detector may not set up properly.  Please consult your owner’s’ manual or Youtube and try to find a good beginner mode  (I cannot tell you how since there are so many detectors.)   Many times the best mode to start out in is “Coins.”  This should set your discriminator properly for the coin garden.

The metal detector is making lots of strange pops and clicks
You may need to change frequencies, ground balance, or reduce sensitivity.   You may also be near electrical interference, such as a pet-containment fence – which is bad news for a target garden.

The metal detector is acting strange and inconsistent
You may need to ground balance – it may be automatic or require a small procedure – but proper ground balance for each location is critical.
You may accidentally have your metal detector in pinpoint mode.  Turn off pinpoint mode and try again.  This is VERY common mistake.

 I hear targets that are not under my golf tees
A new target may have been dropped into the garden.  Find it and remove it – it should be on the surface.  The other issue might be that the garden was insufficiently cleared out before starting.  You may have to sweep the non-teed areas of the garden again (not as easy now with your seeds in place.)

Good Luck, Happy Hunting!!!!