Choosing the right air plant fertilizer
Choosing the right air plant fertilizer can be a bit of a hassle. It’s easy to get lost in all the products that are being marketed. Fortunately, our experts have done the research for you, so you won’t have to.
Fertilizers come in all shapes and sizes. There are granules, liquid fertilizers and ones that you will have to prepare yourself. Often, websites advise using a fertilizer that is specifically designed for plants from the bromeliaceae family of which Tillandsia is member.
Expensive is better?
In truth, plants don’t really care about brands, but only about the content of the fertilizer. There is no difference whatsoever in the chemical makeup of nitrate in a premium fertilizer and a cheap one. So forget about brands and start reading the information on the back.
The first thing to check is the NPK ratio (nitrogen, phosphorus, potassium). A simple rule of thumb is that anything green needs plenty of nitrogen and potassium, while fruits and flowers require more phosphorus. Air plants are very leafy, which is why nitrogen and potassium levels are especially important. Try looking for a fertilizer with a NPK ratio of about 20:5:20.
Nitrogen comes in one of three different possible forms as nitrate, ammonium or urea. It is often told that you should avoid using urea based fertilizers for air plants, because urea requires microorganisms in the soil to break it down into ammonia before it can be used by the plant. Since air plants do not need any soil, using urea would seem a waste of good fertilizer.
But this is only half the story. Like other plants, Tillandsias have the enzyme urease. They are therefore perfectly capable of taking up urea and breaking it down by themselves without the help of bacteria. In fact, urea is far superior to either nitrate or ammonium, because its particles are uncharged. Instead of avoiding urea, it should be your primary source of nitrogen!
The acidity, or pH of your nutrient solution is extremely important. Tap water is often slightly alkaline at a pH of around 7.5. Most plant nutrients dissolve best at a pH of 5.5 – 6.5 which make them better available for your plants. Therefore, always check the label if the pH of the fertilizer will bring your watering solution within this range.
EC, or electrical conductivity is just a technical term for the salt content of your nutrient solution. The higher the concentration of your fertilizer, the more salts are dissolved and the higher the EC will be.
Safe EC levels vary per species. Whereas tomatoes can handle concentrations as high as 2.5 dS/cm, air plants are sensitive to high salt concentrations which may cause fertilizer burn. Safe levels are approximately near 0.5 dS/cm,
One thing to keep in mind is that urea does not increase the EC of your fertilizer, since it is not ionic. Another reason to prefer urea over nitrate or ammonium!