Organic gardeners have a number of natural fertilizing options when their gardens need nutrients. One of these is green sand, which is also known as glauconite or greensand.
Green sand is an organic fertilizer that contains the deposits of minerals that were once part of the ocean floor. Also called "glauconite," greensand has a bluish-green color. The nitrogen-phosphorus-potassium (NPK) ratio for greensand is approximately 0-0-3. It is a good organic source of potash (important for overall plant health and disease resistance) and can also be applied at a rate of 50 to 100 pounds per 1000 square feet to improve clay soils.
What is Green Sand?
Green sand, or glauconite, is a material from the ocean floor that is mined to be used as a soil conditioner or fertilizer. It is made of marine potash, silica, iron oxide, magnesia, lime, phosphoric acid, and about 30 other trace minerals.
It is useful on hard clay soil to texturize it and boost the nutrient content naturally. Sandy soils can also benefit from green sand because it may increase the moisture retention capacity.
Actually, green sand is nothing new. It's been around for decades and is a popular tool that organic gardeners use to fertilize their soil. It is one of the best certified organic potassium sources and contains a high level of glauconite.
There are many benefits to using green sand in your garden. It can enhance soil structure. It also can increase the plant root growth. It is good for the overall health of plants because it gives them more nutrients. Green sand is also a useful component of container garden soils and seed starting mixes.
How to Use Green Sand
Green sand is not water soluble so it has to break up in the soil. It is applied to the soil and not mixed in water.
Generally, you should mix two cups of green sand into the soil around individual plants and trees. It can also be used in a broadcast application--using 50 to 100 pounds for each 1,000 feet of soil treated.
Other guidance says to apply at 16 pounds per 1,000 square feet on lawns and at 30 pounds for flower and veggie gardens. You can add 1/3 cup per bush and two tablespoons per gallon of potting mix.
Unlike artificial fertilizers, it is safe to touch.
Apply it during early spring. It is also useful on sensitive plants and should not damage them.
Most gardeners agree that green sand is a very beneficial natural fertilizer for a variety of reasons. Again, it is not toxic to humans or animals, so if you have pets outside near plants you will not have to worry about exposing them to something toxic. It is also not harmful to all of the important microorganisms (and worms) in your garden soil, which is great since you probably worked hard to create healthy soil.