Fertilizer help

[jax133jax]

I bought two types of fertilizer from a local shop. One is for the orchids when they're in bloom, and one is for when they aren't. They aren't labeled and they look the same. The only difference is one says 18-18-18 and one says 15-30-15
If anyone knows what the difference is, please let me know.

[Bud]

go back to the local shop and ask which is which and label it properly

[silken]

The 15-30-15 is a bloom booster. It's not really for when they are in bloom but to stimulate them to bloom. So basically before you see bloom spikes but suspect that they should start producing them-usually a few months before their bloom time. The other is a balanced fertilizer of nitrogen , phosphorus and potassium in that order as indicated by all 3 numbers being the same. You would usually use this one except when trying to get them to bloom.

[RosieC]

yes the 15-30-15 is the bloom booster.

The idea is that lower nitrogen and higher Phosphorous help stimulate blooming. However many argue (and I tend to believe them) that higher Phosphorous does not help, it's the lower nitrogen that helps. In which case you could just use the same fertiliser year round and use it weaker to stimulate blooming.

If you use any balanced fertiliser at the mixing rates Ray advises on his site (see the link) and use it year round, then orchids will both bloom and grow on their own schedule. That's what I do and it works well.
Fertilizer Mixing Calculators

Note that if you use Ray's mixing then which ever of your two fertilisers you use the nitrogen level will end up the same. I used to have a bloom booster and I just used it up using Ray's mixing rate as thought it were a standard fertiliser. I've not bothered with one again and now use the same fertiliser year round.