Fertilizer Tips

Home Grown  by Keith Reed
In a typical year, the Payne County Extension office typically will review and offer recommendations on over 500 soil samples. Based on these reviews and follow-up with our clients, here are some tips to help you navigate the supplemental fertilizer process.
  • While compost is not the same as fertilizer, it does contain some of the same nutrients. However, the real value in applying compost is its ability to allow the plant/soil/microbial/nutrient/moisture complex to function as a healthy (and interconnected) system. Regular applications of compost will go a long way towards helping plants be as healthy and efficient as they can be, as well as reducing the need for supplemental fertilizer over time.
  • When considering fertilizer, it is helpful to understand the concept of plant availability, or release rate. While this principle applies to all plant growth, it can be easily summarized with a bermudagrass lawn example. Urea, typically sold as 46-0-0, is a common inexpensive nitrogen source. It is also very quickly available or fast release. In other words, when you apply it, you may need to mow every few days as the bermudagrass responds with a quick flush of dark green growth. Then, after a just a few weeks, the growth rate will slow significantly.
  • In contrast, slow release fertilizers do just as described, they release nutrients slowly over time. This process can either happen naturally, as in the case of rock phosphate, which is a hard mineral that degrades slowly. Or it can be some form of manufactured process as is the case with a product such as sulfur-coated urea.
  • Organic fertilizer sources are typically slow release, unless you are dealing with an animal manure source that has not had time to properly age. Synthetic sources can be either slow or fast release. Expect to pay more for the slow release products.
  • All plant nutrients are important but it is nitrogen that is used in the greatest amount and drives plant growth. Nitrogen is a very mobile nutrient, meaning it will move around easily in the environment. If the plant does not use it, it will be lost through leaching, runoff, or volatilization. Reducing these losses are another reason to use slow release fertilizers.
  • It is not uncommon is our area to find soil pH out of the normal range for healthy plant growth. When this happens, adding additional fertilizer will do nothing to help the plant until the soil pH is corrected. If you have plants that are not responding to fertilizer, this is likely the issue. Contact our office if you need information on having your soil tested.
  • While we never know for sure until we are deep into one, this summer is shaping up to be a dry one. Plants that are heavily fertilized with nitrogen will require more water than those that are not.
For more information on this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

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