Watering with rain water

[Kevstar]

Hi guys,

I remember reading somewhere that if you water using rain water you should use fertiliser with every watering?

Would I be ok to use a weak dose of fertiliser on every water and then flush it every so often?

I don't want to over fertilise, but equally, if rain water has little nutrients then i don't want to under fertilise either.

Thanks

[WeirdGuySeattle]

Rain is awesome and depending on how its collected will have some nutrients in it - like from a roof..

I collect rain water, and try to remember to fertilize at least once a month or more in periods of active growth. Typically I fertilize once a week with a weak solution.
Every watering might be overkill unless you are really trying to push a plant. If you have heavy feeders, I'd go with a heavier dose once or twice a month (during active growth).
Otherwise, weekly fertilization at a weak solution (when actively growing) usually works pretty good.

[Ray]

There is no "must" fertilize, but to me, your original concept makes the most sense.

In nature, orchids are fed every time it rains, which happens very frequently, but the concentration of nutrients is very low, consisting primarily of host plant exudates, settled dust, and bacterial and fungal secretions.

If you feed at a very low-dose (I recommend 25 PPM nitrogen – divide 2.3 by the %N on your fertilizer label for the for the milliliters of fertilizer per liter of water) and water heavily every time, your plants will be very happy and really won't need to be flushed periodically.