UNDERSTANDING THE ORCHIDS NATIVE ENVIRONMENT FIRST
As beautiful and unique as they are, orchids require the same environmental conditions as any other plant in order to survive and thrive. These necessary conditions are heat, light, nutrition, water and oxygen, with each individual plant species and family requiring differing amounts of each. Outside of watering, understanding how to feed orchids effectively will make the biggest difference in the health of these plants and the quality of their flowers.
Because of this, the roots of epiphytic plants have evolved to become more than just a structure used for support, and nutrient and water uptake. In the specific case of orchids they are also used for water storage and - rather impressively – to house chlorophyll pigment so that the roots can produce energy rich sugars through photosynthesis along with their fleshy leaves.
As mentioned previously, in their natural habitat epiphytic orchids live high up in the canopy often secured to a suitable branch. Although this makes them safe from grazing predators it also puts them well out of reach from life giving ground water and the nutrients locked up within the soil. In order to obtain their essential nutrients orchids have to rely on accumulated debris, bird and animal droppings to be washed onto their roots by rain.
All of this means that when it comes to feeding orchids effectively, which is why it helps to understand the environment they come from.
HOW TO FEED ORCHIDS
Using the normal concentration of water soluble fertilizers that you would use for other plants will quite simply overfeed orchids burning their roots and leaves, and cause fertilizer salts to build up in the growing mix. This is caused by the phenomenon known as ex-osmosis. The dictionary explanation of osmosis is a follows:
Osmosis is the diffusion of water through a semi-permeable membrane, from a low concentrate solution (high water potential) to a highly concentrated solution (low water potential), up a solute concentration gradient.
Ex-osmosis occurs when water contained within the plants root is drawn back out into the root environment due to the high concentration of nutrients compared to that within the root. If exposed for too long the root cells will die through dehydration causing the characteristic burn marks on the surface of the roots.
Over-feeding orchids will not make them grow faster, or flower more, but instead will push them into decline and even die. However there are some basic orchid feeding rules with will prevent this from happening.
1. If using a standard house plant food always feed your orchids using half the recommended strength. If in doubt, always feed less.
2. Purchase and use orchid fertilizers specially formulated for orchids and simply follow the directions.
3. Try not to get into the habit of feeding orchids the same amount of feed at the same time each month. Orchids will need more feeding in the spring and summer months while they are actively growing, and far less during the cooler winter period.
4. You can’t treat all orchids the same and this includes the amount of fertilizer given. Give larger growing specimens or species that naturally produce more foliage – cymbidium species – more food than other those that grow naturally smaller or produce less foliage such as plants from the paphiopedilum family.
Together with feeding your orchid plants and to reduce the risk of over feeding it is also a good idea to flush the root system thoroughly with water at least once a month to get rid of excess salts.