How to Fertilize your Orchids

Doritaenopsis orchid
Doritaenopsis Little Gem Stripes 'Stars' blooms prolifically.

* Basic orchid food provide nitrogen(N), phosphorus(P) and potassium(K) This N-P-K ratio corresponds to the fertilizer ratio shown on the package, such as 30-10-10 or 10-20-10.
Fertilizers high in N are formulated for growth, while those high in P generally encourage blooming.

* Many orchid foods are high in urea nitrogen, which takes time to break down, and  is washed out of the mix before it is of any use to the plant. A non-urea nitrogen formula will provide nitrogen in a form immediately usable by the plant. U se a high nitrogen fertilizer with bark mixes--this increases bacterial activity which then provides additional nitrogen in usable form to the orchid.

A dilute Organic Orchid Fertilizer   can also be applied a a foliar feed to the lower leaf surface.





Phalaenopsis will do well with regular fertilizing, but will suffer, like most orchids, if excess fertilizer is applied. As a rule of thumb, apply house plant fertilizer at half the strength recommended for indoor plants. Fertilizers formulated for orchids are now widely available so we suggest you use those-simply follow the instructions prvided by the manufacturer.

F or phalaenopsis orchids potted in a bark mix, use an orchid fertilizer with a higher nitrogen content (such as 30-10-10) or a 'urea-free' formulation. For those plants in a peat-based mix, or sphagnum moss, a  balanced 20-20-20 formulation or 20-10-20 is fine(see box for more information).

In both cases, switch to a 'blossom inducing' fertilizer (such as 10-20-10) once new leaves have matured, generally in the later summer and continue to use this during flowering.  Alternatively, switch between fertilizers each time you feed.

Fertilize plants 2-3 times a month during the warmer months and 1-2 times per month during the winter when growth is slower. Unless you are using rain, or reverse osmosis water that is very pure, you should  flush your plants thoroughly with water at least once a month to get rid of excess salts.

Remeber, orchids do not need as much fertilizer as other house plants or garden plants. If you overfeed your plants, they will not grow faster or bloom better. Instead:

- you will cause salts to build up in the growing mix which will damage roots and slow growth
-you will waste your money
-you will pollute the environment as the excess fertilizer salts eventually will end up in ground water

- Many growers, myself included, follow a 'weakly weekly' fertilizer schedule, This means you fertilize you orchids every week but only at about quarter-strength. The advantage of this is that plants receive a consistent amount of food at all times. You can adjust the amount of fertilizer you provide depending on the season slightly.

Non-urea low-strength
organic orchid fertilizer can be applied frequently to your orchids with little chance of overfeeding. It comes in  a spray bottle so can also be applied as a foliar feed to the underside of leaves, and roots which orchids benefit from.

Premium orchid food have added micronutrients such as calcium, magnesium boron, copper etc that plants need these in very small amounts to stay healthy. This is less of a worry if you use tap water which often have many of these nutrients in them.  Nevertheless, its a good idea to use a premium orchid food, about once a month just to be sure your orchid is getting what it needs beyond the basic N-P-K formula.  If you are using purified reverse osmosis (RO water) which has no nutrients, you will definitely need a complete orchid food formulated especially for RO.