Back to Basics . . . Part 20 Granular fertilizers vs. Soluble fertilizers ? Granular fertilizers as opposed to soluble fertilizers are the common fertilizers that are applied to the soil around the plant and are dissolved either by irrigation or rain water. They are usually a combination of slow and fast acting nitrogen, but also contain phosphorous and potash and the better ones will also contain trace elements. These are the more economical but somewhat slower acting (days or weeks) than solubles. The granular fertilizers are safe to use, if used according to the manufacturer’s directions. Remember you can overdose and cause burning if you overdo. Depending on the blend of fast and slow acting nitrogen, you can probably go two to three months between applications as a general rule. Unless the fertilizer contains a large percentage of water insoluble nitrogen it could be dangerous to use on potted plants. Solubles, on the other hand, are safe to use on potted plants because once the proper amount of fertilizer is dissolved in water, you cannot overdose. Nutrients are absorbed quickly (within hours, especially if foliar fed. Foliar feeding is the process of spraying nutrient solutions on the leaves where some of it is absorbed directly and the balance that falls to the ground is absorbed by the roots. Follow label directions carefully. The main disadvantage of solubles is, that since the nutrient solution is very dilute (it has to be to prevent burning your plants) you must feed weekly to supply proper nutrition.* Another disadvantage of soluble fertilizers is that it is about 5 times more expensive than granulars to supply the same amount of nutrients. The cost factor is insignificant when you have a few potted plants, but would become quite significant if you are fertilizing your entire property. * Another option here would be to use a time-release fertilizer such as Osmocote. This is a manufactured material, the particles of which look like little round beads. The nutrients are impregnated in these beads of a resinous material and are released slowly according to temperature. The warmer the soil temperature, the faster the release. Because of this feature, the release of nutrients are matched approximately to the demand of the plant. This is the essence of fertilizer theory. A thorough understanding of these principles will save much time and money over the years. NEXT: What are Mulches?
Posted on: Wed, 06 Nov 2013 12:39:49 +0000