Ought to Gardeners Use Greensand Fertilizer?
Greensand is an natural fertilizer that has been round for a few years nevertheless it has by no means change into widespread besides in licensed natural farms. Are gardeners lacking out on an essential soil modification and supply of potassium?
What’s Greensand?
Greensand fertilizer is a pure soil modification derived from historical marine deposits, primarily composed of glauconite, a inexperienced mineral that accommodates vitamins vegetation can use. It has been used for hundreds of years in agriculture for its capacity to supply potassium and a few micronutrients to soil. The mineral’s inexperienced colour comes from iron, potassium, magnesium, and hint components.
For the reason that mineral is mined and minimally processed it does qualify as an natural modification that slowly releases vitamins. Gardeners sometimes combine it into the soil earlier than planting or apply it as a high dressing round established vegetation. It may be utilized in vegetable gardens, flower beds, and even lawns.
It’s mined from numerous areas and the particular composition will rely upon its origin.
NPK of Greensand
A typical NPK present in business merchandise is 0-0-3, however the potassium degree will be as little as 0-0-0.2. Claims that this can be a good fertilizer are unsuitable because it offers no nitrogen or phosphorus.
It does present different vitamins. One product claims that it has “68 Minerals and Hint Parts”. It could include that many minerals, however most of these aren’t utilized by vegetation that solely use about 24.
Some sorts of greensand do have greater ranges of calcium, magnesium, and iron, however these aren’t poor in most soils.
Soil Conditioner
Glauconite typically exists as sand-sized pellets, as proven within the photograph under, and doesn’t behave like sand when added as a soil conditioner. Not like sand, it holds a good quantity of water and might improve the water retention capabilities of sandy soil. It additionally has a comparatively excessive cation trade capability (CEC) giving it the power to carry plant vitamins.
Comparability of CEC values:
- Greensand: 0-30 meq/100g
- Clay: 20-60 meq/100g
- Natural Matter: 100-200 meq/100g
When added to clay soil greensand provides porosity and loosens them.
The Downside With Greensand Fertilizer
This fertilizer is a type of rock, just like rock mud, and has been within the floor for thousands and thousands of years. It’s fairly secure, so the potassium and different vitamins in it is going to be launched very slowly.
The vital query is, how sluggish is sluggish? Whether it is too sluggish it’s ineffective for gardens.
Clemson College experiences that vitamins are launched “very slowly”, that means years. Rutgers College did an intensive evaluation of the literature in 2002 and located combined outcomes with some tasks exhibiting elevated yield and others with no impact. The overall consensus was that potassium is launched too slowly in most soil to be efficient.
Greensand additionally accommodates heavy metals together with arsenic, cadmium, chromium, and lead.
A pot experiment utilizing acidic (pH 4.5), tropical soil discovered that greensand did improve plant progress. Potassium is launched quicker in very acidic situations.
One other examine concluded that greensand launched potassium very slowly over 50 years and that different sources of potassium can be required to satisfy crop wants. They advocate it solely be utilized in naturally acidic soils and soils that include manganese oxides as a result of each situations improve the discharge charges of potassium.
In an article known as, Managing Potassium for Natural Crop Manufacturing, Robert L. Mikkelsen concluded that “the Ok launch charge is simply too sluggish to supply any important dietary profit to vegetation at sensible software charges”. Any will increase in yield are most likely attributable to improved soil traits.
Ought to Gardeners Use Greensand?
Greensand merchandise marketed to gardeners promote the concept they add potassium to soil, however except the soil may be very acidic, under 5.0, it’s not going so as to add sufficient potassium to make a distinction in plant progress. Don’t use it as a potassium supply.
It does have some worth as a soil modification when added to clay or sandy soil. It improves moisture retention and will increase the soil’s capacity to carry vitamins. It additionally loosens clay soil.
The issue with this product is that it’s often offered in small luggage at a really excessive value, making it unsuitable to be used as a soil modification. It’s cheaper and significantly better to make use of compost.
I can’t consider any good motive for gardeners to purchase this product except they will get it in bulk at a low value. Even then, compost can be a greater choice.
