This past year we have had a few customer complaints regarding the use of Nature Safe on 100% sand greens. The USGA green section is on occasion recommending 100% sand on grow-in construction greens. I am very sorry to see this happening because without organic matter present, it is very difficult to establish a healthy microbial population in the soil. An established and prolific microbial population will help maintain soil and plant health and vigor.
Why are we having these complaints? Superintendents are using good logic and attempting to compensate for the lack of organic matter in their sand greens. That is why they are selecting an organic fertilizer such as Nature Safe. The problem comes when your organic begins to breakdown. The first product released is ammonia. In normal soil conditions, we have organic matter, which will provide sufficient cation exchange capacity to retain the ammonia until it can be utilized. Without the organic matter the ammonia is released as a volatile gas and will escape into the atmosphere. This problem will occur with any organic and also any synthetic in which nitrogen is converted to ammonia. We strongly recommend the incorporation of at least 10% organic matter in your new construction greens. This will allow for a much healthier soil and plant environment for the initial grow-in as well as after the turf is established. Microorganisms do not thrive in sand; therefore, they will not establish themselves and provide the benefits to the turf as in normal soil conditions. Imagine if you were in the desert with no food, shelter or protection. You would not fare well, either. This is exactly what a microorganism will encounter in a 100% sand environment.
If you have already made the commitment to 100% sand, then I would recommend a soluble program of nutrition along with small amounts of Nature Safe 5-6-6 initially until you can develop some organic matter in your soils. Nature Safe 5-6-6- contains humus, which has a high cation exchange capacity and will aid in retaining available nutrients against leaching. It usually takes at least a year to establish a microbial population. Applying organic matter will help you increase holding capacity in the sand, which normally has very little. We are currently developing a soluble organic fertilizer that we hope to have available in 1999. This will allow you to add organic matter in a soluble form. As we learn more about this hydroponic growing condition, we will keep you informed.