The Inorganic Element to Organic Gardening
This final article in the series Organic Fertilizers is focusing on the minerals that soils and plants need. Mineral are inorganic, and the process for their use is different from other organic fertilizers.
Microorganisms will devour the minerals and then, their waste and enzymes they produce make the nutrients available at the roots of plants
Plants need 17 elements for a balanced diet. Most chemical fertilizers have the three main element of Nitrogen, Phosphorous, and Potassium. However, the other 14 listed above – are usually not available to the soil from these products. If even one element is missing, the garden plants may survive, but they do not thrive.
Think of these 14 elements as part of a construction site. The N-P-K is the major structure – the trusses, the floor joists, and the wall studs. The remaining macronutrients, and micronutrients are the nails, and screws that hold the structure together.
Ok, so one screw gets omitted. Most likely the structure won’t fall down. But if 3 – 4 screws are left out, the structure can get wobbly. And lets face it, if even 10% of the screws are not installed, the whole thing can collapse. Likewise, the balance of the nutrients available to the plants is critical. If even one element is missing the plant suffers.
As I always remind my readers, have a soil analysis done before adding fertilizers and minerals to the soil. One, your soil may be adequate for what your are growing and you do not need to apply anything. Two, you may spend money on a product that you do not need, and omit the elements you do need. A soil test is always a smart first step.
Now, having said all that, here are some mineral products that may be useful in the garden and landscape.
Rock Dust, also called rock powder or stone meal, has an interesting story. An 18th century grist miller named Julius Hensel, noticed, one day that rocks accidently made it into his product. He removed the contaminated product to a back portion of the property. Soon he realized that this forgotten part of the garden was lush and growing better than other parts. Over the next years, Hensel documented the crops growth and even spread this rock dust around fruit trees that were wormy. The trees started to product full, fleshy fruit and the community all wanted this Rock Dust for their crops. The Bread from Stones story by Julius Hensel is available here
Rock Dust remineralizes soil.It can supplement worn out, over worked soils with calcium, iron, phosphorus and potassium. It increases bacterial activity in the soil and promotes root growth. Rock dust also contains 57 different trace elements and can not burn plants as it is slow release by the microbes. . The soil is loosened by Rock Dust, and as it breaks down into humus, carbon dioxide is better absorbed from the air and provides better water retention.
Epsom Salts is a highly soluble substance that occurs naturally. Because it is soluble, plants can benefit from foliar feeding as well as saturating the soil beneath them. Magnesium, an element necessary in the chlorophyll of plants, is found in Epsom Salts. Crops such as tomatoes, potatoes, roses, and peppers need magnesium and Epsom Salts can supplement magnesium
Gypsum is a sedimentary mineral found in evaporated beds of other minerals. Ocean brine and salt domes supply these deposits. Limestone, and shale can also be mined for gypsum.
Gypsum will bring Calcium and Sulfur to plants. It can increase the pH levels of acid soils, and it can reduce Aluminum toxicity in acid soils. Gypsum will not correct soil compaction. Good organic material like compost will break up hard soils better and do not work the soil when it is wet. This can cause air and water to be pushed out and become compacted.
Greensand – is mined from old sea beds. It is rich in potassium, but also contains phosphorous, magnesium, iron, silica, lime and trace elements. The U.S mines greensand in New Jersey and can help break up compacted soil.
Rock Phosphate – is a fine powder that breaks down from microbes feeding on it. Phosphorous is a element that encourages root development in plants. Phosphorous does not move through the soil readily, and most soils have a residual supply. Again, here is when I’d recommend a soil analysis before applying phosphorous to the soil. Commercial applications of phosphorous have increased to accommodate crops that are grown for biofuels. And this increase in usage will deplete the reserves in the U.S. in thirty years. China and Morocco also produce Rock Phosphate, but their reserves will only last 75- 100 years.
This is algal bloom. Many Ohio waters are being affected by this excessive growth and it is reducing oxygen levels to the point that fish die-off is apparent. Grand Lake in St. Mary’s Ohio, as well as Lake Erie are victims of this problem. As homeowners and farmers apply fertilizers, it is the phosphorous that is the cause. Since phosphorous does not move through the soil readily, it is the fertilizers themselves that are pouring into the streams and lakes. The algae is difficult to control, and agencies and communities are pouring funds into projects that may or may not succeed trying to control the algae bloom.
As with anything, mineral supplements can greatly enhance crops and yields. While indiscriminate usage can cause major problems in the soil and in the watershed. Some fertilizer manufacturers are creating products that have no phosphorous due to community restrictions.
The soil analysis is, here again, worth checking before any amendments are applied.
Thanks for following this series on organic fertilizers. If you have any questions, please ask in the comments form.