Science behind Orchid Fertilizers..Right Dosage

Orchid fertilizers come in a variety of forms and to rightly measure the correct amount of fertilizer is always a challenge for a orchid grower.

I picked up a TDS meter (HM Digital) in ebay and I use the PPM reading to right feed the orchids.

Items Required

1) TDS Meter
2) Rain Water/Borewell Water/BWSSB Water
3) Orchid Fertilizer in a powder form or liquid form

I had started collected rain water in a 500 litre drum which we had used during our house construction and I will use the rain water.

I use a powder form of orchid fertilizer (20-20-20) with micro-nutrients

Following is a short process

1) Remove the cap of the TDS Meter
2) Dip the TDS Meter in the water without adding the fertilizer. Note down the reading. My rain water reading was 20 which is ideal.
3) Now add a tea spoon of orchid fertilizer and stir the liquid so that the granules dissolve in water
4) Measure the TDS of the liquid again.

The ideal feeding level on a weekly feeding routine is around 200 PPM. which means that the TDS meter should show 220. (220 of the solution - 20 of the original solution) = 200.

if the PPM is higher then add more water to lower the PPM and if the PPM is lower than the desired level then add a small pinch of fertilizer , stir and measure again

I weekly feed my orchids with this weak formula