An informative piece from our new friends at Plant And Be Happy
Modern agricultural science considers soil in terms of chemicals. A better way to see the soil is in terms of energy. Energy flows between the earth’s two poles.
The various mineral compounds in the soil allow this energy to flow in different amounts. If you get too much mineralization you can have too much flow. Too little and you won’t have enough energy flow.
Let’s take a practical example. If you fill a bathtub with distilled water, turn on a hair dryer, and drop it in, what will happen?
Nothing – because it is distilled water.
Now add some minerals, such as epsom salts – which is magnesium sulfate, two necessary minerals in the soil. If you’re in the tub of distilled water when the hair dryer is dropped in, and you slowly add epsom salt, at some point your body will start to tingle. As you keep adding more you’ll start feeling uncomfortable. Keep going and you’ll get seriously shocked, and if you get enough salts in the water, you’ll kill yourself instantly.
Please don’t try this experiment at home!
It is the same with plants. You might hear about “burning the plant roots” by adding too much fertilizer. What’s actually happening is that there is too much electrical current flowing, that’s what burns the plants. Mosture content also impacts this – if your soil is very wet the plants won’t get burned as much, but when it starts to dry out a little then they’ll get burned more. It’s like letting the bathtub water evaporate – the mineral concentration is getting higher and the energy flow increases.
Now suppose there is a natural current in the water that you can’t turn off. And you want to take a bath, and you want some epsom salts because it’s good for sore muscles and you worked hard in the garden all day. How do you prevent yourself from getting shocked? (Remember there is a hypothetical current that you can’t turn off.) How do you know how much epsom salt you can safely add?
You can test the conductivity of the water for minerals already in solution, and only add epsom salts if the conductivity is low enough. And you can test while you’re adding to make sure you don’t add too much.
Similarly, suppose you need some minerals in your garden, because you see some mineral deficiencies in the plants. An example can be found here: http://4e.plantphys.net/article.php?ch=3&id=289.
But how much should be applied?
Test the conductivity of the soil. If it is already high and you add more minerals you can burn the plants. This also applies to organic fertilizers, although there is less chance because most organic fertilizers have lower percentages of minerals.
Therefore we only fertilize when the conductivity is low. This won’t tell you what minerals are needed – that is done with a soil test and by watching the plants for signs of nutrient excesses or deficiencies – but it will tell you whether or not it is safe to add nutrients, and prevent you from adding too much.
How do you test your soil conductivity? The easiest and cheapest way is with an electrical conductivity meter (EC meter). You can buy them online for as little as $30-40.
If you have a TDS meter (Total Dissolved Solids) you can also use it - but you have to convert the reading by multiplying by 1.7. TDS meters are often sold with RO water purifier units. For more detailed information on conversions between EC and TDS see http://www.hydroponics.net/learn/debate_over_ec_and_tds.asp
First prepare your sample to test. Take a small sample of soil in one cup, and mix it with an equal volume of DISTILLED water from another cup. The soil should not have any pieces of organic matter in it. ½ cup of soil and ½ cup of water is sufficient. Stir the mixture up really well and let it sit for about 10 minutes. Stir it up again, and take a reading by inserting the meter tip into the mixture.
If the number is less than 200 you should fertilize. (Remember to adjust the reading for TDS meters.) What kind of minerals you add will be according to the soil test results or according to any mineral deficiencies you see in the plants. Don’t just add indiscriminately unless you can see that you need it, or based on the annual soil test.
Conventional agriculture often says (as an example) “side dress with x amount of nitrogen after two months.” The result is often a waste of fertilizer, and over-fertilization which can bring a host of other problems – not the least of which is pollution of water supplies. Excess nitrogen can also increase pest problems and produces low-quality food.
Conductivity around 200 or below means your plants will not grow much. Conductivity at around 1000 means you have far too much nutrients or salts already, which will usually be evident by problems in the garden such as root rot, nematodes or plant wilt.
If the conductivity is above 600 then you should not fertilize unless you really know what you’re doing, because there is a good chance you’ll burn the plants. And if is between 200 and 600 then you can fertilize, but do so with caution if it is above 400. A range of around 200-500 is very good for robust growth.
In new gardens that are actively planted you sometimes cannot put the full quantity of minerals needed all at once, because you might burn the plants. Some beginning soils are very deficient in nutrients that the plants need. If your soil is in the upper range it is better to fertilize more frequently with less fertilizer, cautiously.
Fertilizers include organic sources such as seed meals, and any other type of fertilizer or soil amendment. If you’re adding compost, you can also test the conductivity of the compost itself. Finished compost should have a conductivity of around 1500, whereas unfinished compost (which should never be added to the garden) can be as high as 100,000.
Remember the first rule of high brix gardening is to only put into the soil what the soil needs, and that is based on the soil test. (Get the weak-acid test, also known as the Morgan Extract.)
For more detailed information here are two great sources.
And when you’re finally finished in the garden for the day, take a nice epsom salt bath for those sore muscles, but without the electricity!