We look for things in the ground…

… but there is more than one type of ground, and there are some differences in what works for different types of ground. This blog entry is about the differences in the types of ground and what setting and machines and approaches work well, typically. Now, does that mean that these are the only ways that work? Nope – nor do they guarantee success as even the best machine can only find what is under the coil but you may be able to alter the odds a little in your favour.

I won’t really be discussing types of ground that we just don’t see in the South East of England. The red sands of Australia or the heavy mineralised soils of Minnesota are very different to the rolling South Downs or gentle pastures where we normally detect. We also don’t hunt in parks the way that a lot of American detectorists do – and we do not want to use notch discrimination the way that they do. If you look at some detectors, they are designed for the US market and have indicators for dimes, quarters and so on. That is probably handy for hunting trashy parks for shallow finds in New York but not helpful for relic and coin hunting in the South of England – which is not to say that the machines won’t make finds, just that the US specific settings won’t help here.

The most different type of soil is wet beach sand. Water is an electrical conductor but not a good one if it is pure. Salt water is a good conductor. Unless a detector is designed for saltwater detecting, it is absolutely going to struggle on wet sand. Pretty much any detector will work fine on dry sand but if they are not designed for wet sand, they will give false signals all the time on wet sand due to the conductivity of the soil. That doesn’t mean that you can’t find things on the beach, but it is a limiting factor. On dry sand, you will typically find modern coins, maybe costume jewellery, and a lot of modern trash such as vapes, cigarette lighters, foil, drinks cans, bits of disposable barbeques, endless amounts of foil, and the ever popular aluminium nugget that was once a beer can that got melted. In wet sand, you can find historical artifacts on a good day but salt water is not kind to metals. Silver can survive and gold never corrodes so maybe you will get lucky and find jewellery, but generally, really old finds are uncommon on a typical site. That said, Roman coins have been found on beaches were there was a roman presence. Modern finds on dry sand tend to be fairly shallow and it is rare to get much depth on wet sand.

Inland, there are different types of land and they generally become accessible to clubs such as SES at different times of the year.

Plough Soil / Arable land is a great place to detect in my opinion because it often produces good finds and there is no archaeology to destroy. The first foot or so of soil gets turned over by the plough and so there is no stratigraphy and no context to speak of. It also means that items deeper in the soil get brought up to the surface a lot which means that even relatively shallow detectors have a decent chance of making good finds. However, plough soil tends to have a LOT of iron it, often big chunks when the ground is stony as that damage ploughs, plough socks and harrows.  Chalky soil (and there is a lot of that in the South East) tends to be rich in flint and big flint nodules can break iron ploughs pretty effectively. That said, flint was an important natural resource to our ancestors and anywhere that supplied it was likely to be occupied in Neolithic times – and that often meant that there were still people there is the bronze age and iron age.

Digging plough soil can be relatively easy depending on how stony the ground is but in a hot summer like the one that we have just had, can be challenging. Filling the holes is simpler though as we don’t need to worry about matching up the turf as we would for pasture.  Because iron is common in these fields, it is best to have a short recovery time on your detector if that is an option – that determines how quickly the machine recovers from iron which makes a big difference in noisy soil. Large coils are not ideal where there is a lot of iron about and generally, smaller coils, fast recovery and lower sensitivity settings will work best in these conditions. It is possible to work with a big coil and still make good finds but you are likely to dig a lot of trash as well as good targets. We often find the ever common .303 rounds (tens of billions of them were made), shotgun shells and some modern waste.

One major hazard is that “Green waste” is sometime spread on fields these days – Green waste is supposed to be composted garden and park waste but very often contains screws, can slaw (finely chopped drinks cans), electronics waste and similar non-biodegradable components. This is not a wholly new problem though – middens were often spread over fields, but I would much rather find a medieval shoe buckle than a rusty bolt from a park bench. Anyway, on noisy plough soil, small coils tend to do well. This is especially true on fields with wheat stubble where a small coil can work between the rows, but large coils can sometime bash the stubble aside with considerable effort. Because plough soil gets rotated by the plough, depth is not something that you need a lot of from your detector. Coke (the mineral, not the drink) can also be found in these fields if steam engines with chain ploughs were used at some point. This generally gives an iffy signal much like other types of “hot rock”.

Access to this type of land is very dependent on the cycle of crops. Most farmers won’t let detectorists near seeded ground with good reason. Different crops become ready at different times of year, but this type of land is most commonly available in Autumn when most crops are harvested. High frequency single frequency machines often do well here – hammered coins are generally easiest to find with a high frequency coil and cut halves and quarters are very hard to find with low frequency coils and machine.

Pasture is a very different beast. It tends to be relatively quiet with limited contamination with modern materials – but there are exceptions, of course.  The military trained on a lot of these fields during the second world war – and a lot of the battle of Britain was fought over the southeast of England so the ever popular .303 round is common here as well. Shotgun shells and .22 bullets and cases are also fairly common here as are pistol and musket balls – some of which date back the 1600s and the civil war so they are artefacts in their own right.  

Depth matters a lot here and you will want to get your coil as close to the ground as possible. Generally, large coils give you more depth, especially when run with lower frequency on single frequency machines – which most detectors that you see on rallies are still. The soil doesn’t get disturbed as much and tend to build up over time as the sheep, cattle or horses add their contributions to the soil. That said, good finds can be made with typical single frequency machines that typically run around 15 kilohertz or so. The smaller coils and high frequency machines are often a good bet if you are looking for small coins or cut coins in this type of soil.

Common good finds are Crotal Bells (worn by Sheep or Cows typically) from the 1600s on, horse related finds such as bits of tack or horse brasses, coins (markets sometimes happened on pasture) and sometimes older finds such as bronze age bits and pieces that haven’t been destroyed by ploughing and modern chemicals.

There is a common complication on pasture – very often, there will be electric fences to keep the animals where they belong. These present a small hazard to detectorists but it is easy enough to avoid touching them – if a cow can understand that touching them is a bad idea, most of us can too. However, electric fences don’t work on DC voltages – they have 1 second pulses of high frequency alternating current that interferes with AM radio and metal detectors. You may be able to use some form of noise cancelling on the detector but often the only real option is to move away from the electric fence.

And the most common finds? Well, shotgun shells as mentioned but also the ever present “Moo tube” – small metal tubes that were used to hold cream for treating mastitis in cows. These are single use and farmers and vets often discarded them in field. What sort of finds you make will depend on the depth of your detector and the frequency that it runs on with low frequency and large coils being ideal for depth and small high frequency coins good for hammered coins and small finds. Deep iron is generally less of an issue on pasture.

And finally, there is the most common of all – mixed land where it has been used for both. Some years it was ploughed, some years it was grazed. Some years it was both if the remains of the crops were suitable fodder for livestock. The decision was often based on what sort of produce the market wanted as farming is a business. You often won’t know until land has been detected quite a few times, but the best advice that I can offer is to know your machine and learn how to use it to its best advantage in different conditions.