Home > Great Big Greenhouse Blog > June 2013 > Feed, I Mean, Fertilize Me!

Feed, I Mean, Fertilize Me!

I love breakfast! On days when I do not need to rush to be somewhere, I fix a big breakfast with bacon, eggs, grits, fried apples, biscuits, and so on…whatever I have in the fridge or pantry. My arteries may soon be so stiff that I won’t be able to bend over or sit down. The point is that I have to make my breakfast from the various elements I have on hand.
When we say we are going to feed our plants, we are really just giving them the elements they need to make their own food. Fertilizers supply these elements (mostly minerals) that plants find naturally in fertile soil, but which are often depleted in our man-made landscapes and especially in pot culture. Plants that live in the same pot of soil for a long time, have generally used up the available minerals or “nutrients” that they need for healthy, vigorous growth.  
There are three main elements that plants require in large amounts: nitrogen (N), phosphorus (P), and potassium (K). A complete fertilizer contains all three of these nutrients in differing quantities based on the kind of plant being fertilized. Plants do require smaller amounts of other elements, including copper, iron, zinc and more. Many fertilizers include small amounts of these other ingredients. Get out those reading glasses, ‘cause these can be in very small print. 
The relative amount of each of the primary ingredients is noted on the product as a ratio: N:P:K (10-10-10, 5-15-5, 36-8-10, etc.) For example, ferns need far more nitrogen than they do phosphorus or potassium, so in a good fertilizer for ferns the label might read something like 30-5-5. Flowering plants bloom better when the formula is more balanced, or even heavy in phosphorus (e.g., 5-10-5). Most foliage plants are happy with a balance like 20-20-20. If you have all of these types of plants, use a general purpose houseplant fertilizer as a compromise (Miracle-Gro Liquid Houseplant Food or Jack’s Classic Houseplant Special.) Some fertilizer manufacturers have attempted to make product selection easy for us by using names like “African Violet Food”, “Cactus Special”, or “Palm Fertilizer”.
These primary fertilizer ingredients (sometimes called macro nutrients) are available in products with different application methods. This can be important because if you don’t like using it, you probably won’t. Concentrated liquid fertilizers might require a few drops to a gallon of water, while a time-release product like Osmocote stipulates applying an amount of fertilizer pellets based on pot size. Two more commonly available types of fertilizer are water-soluble crystal granules (you know…the kind that makes your fingers blue) and fertilizer sticks you shove into the soil (compressed fertilizers that release some nutrient each time you water.)
Additionally, fertilizers come in both organic and inorganic forms. While some people prefer to use organic products whenever possible for environmental reasons, the plant doesn’t really care which you use. Organic fertilizers are broken down into the same molecules that the inorganic fertilizers contain before the plant can use them.
Most foliage houseplants are slow-growing, moderate-light plants that use fertilizer at a fairly slow pace. Without rapid growth or constant flowering, plants are not using much fertilizer, and it can be easy to over-fertilize. Unused fertilizer accumulates around the roots and can cause a burn which will show up on the foliage as brown or dried leaf margins. Excess fertilizer can be “leached” out of the potting medium by allowing water to slowly run through the root ball for a few minutes. The general rule of thumb on fertilizing foliage plants is monthly from March through September. This is assuming that the plants will be doing more growing when our day length is long. Plants that are being grown under artificial lights may need fertilizing year round due to the more constant day length.
On the other hand, actively flowering plants or any plant that is growing rapidly will be using the fertilizer, and it should be applied regularly as long as needed. Just as with all gardening, indoor gardeners have preferred methods of fertilizing their plants. Some like to “feed” every time they water, and this is fine as long as you dilute the application rate to ¼ the regular rate.

Bon appetite!

Posted: 6/21/2013 by Margot | with 0 comment(s)
Filed under: MargotGunn, TheGreatIndoors
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