Hi all,
Met an expert who advised that the orchid food is much stronger than our aquarium plant food. That’s all I know.
Last orchid ferts i bought (at Wisley)
The fertilizer Ed bought is a concentrated complete high nitrogen food, just used fairly dilute. It has low levels of phosphorus (P) and potassium (K), if you did it as N: P: K, it is 35:4.4:8. I think that was probably
@Siege's expert meant. The RHS is a prettty good source of information, so I would be tempted to replicate something near their recipe.
The nitrogen content is mainly as urea, which is much safer as a foliar feed (epiphytic orchids take in their nutrients via their leaves and aerial roots, they don't have conventional roots), than ammonia or nitrate, both of which can cause <
"fertiliser burn">.
Baby bio orchid feed is NPK 5.3 -2.2-0.85
So in that case the N: P: K are quoted as P2O5 and K2O, so you have ~5.3:1:0.7
is orchid feed just very weak generic feed?
Yes it is, but with more nitrogen and less potassium, or phosphorus, than we would use for aquatic plants. All nutrients are ions when the plant takes them up, so that all that changes with different fertilisers is amounts, source is irrelevant when they are in solution. Urea isn't an ion, it has to be converted to ammonia via the urease enzyme (in plants and some micro-organisms). Becausse it isn't an ion it doesn't have an osmotic potential and doesn't casue fertiliser burn (the rapid loss of water via osmosis)
Would appreciate any advice as to if it is worthwhile to make our own
Raising the nitrogen level on its own would mean that you would need to use ammonium nitrate (NH4NO3) or urea (CO(NH2)2). Ammonium nitrate is very likely to cause burn, and urea isn't easy to obtain in small amounts, ("Diesel Exhaust Fluid") is probably your best bet.
Urea is really cheap to buy in industrial amounts, so it is often the nitrogen source in <"
cheaper foliar feeds">. You could use that as a base.
cheers Darrel
