A couple of questions on fertiliser

[ArronOB]

A while ago I bought two packets of locally-produced fertiliser.

One was described as a regular food and the other as a ‘bloom booster’.

Their NPK formulae are
22/3.7/14
And
15/3/25
respectively.

I have since read here that the distinction between growth and flower-boosting fertilisers is a myth - that’s good, any simplification is good.

Anyway, I’ve now used up all the regular growth formula but haven’t touched the bloom booster. My question is should I use the bloom booster as a regular fertiliser, or toss it and buy some more regular fertiliser??

I should explain my focus is not to extract the very last mm of growth out of the orchids, but I don’t want to use something which is essentially useless either.

And the second question. Outside of winter, I hand water my 200plus orchids with fertiliser weekly, and hand water with kelp solution every month or two. Is there any problem with mixing the two together, and saving myself a bit of time?

Cheers
Arron

[Orchid Whisperer]

Either of those fertilizers should be fine on a regular basis. Generally, all plants need/use more N and K (1st and 3rd numbers) relative to P. In nature, orchids take whatever nutrients they can get, your fertilizers just match the nutrient "need" profile better than most.

You could mix some fertilizer with the kelp solution, but you don't really need to. Remember that kelp also provides nutrients.

[SouthPark]

I think anything that works nicely for a very long time - or indefinitely - will be excellent. I just use the yates liquid orchid fertiliser 10:3:14. But I wouldn't hesitate at all to use either of your mixes --- ie. 22:3.7:14 or 15:3:25. I go weak application monthly - followed up with cal-mag a couple weeks after the fertiliser application.

I reckon that if the plants can get whatever they require, then the exact ratios don't matter that much - except maybe for optimisation purposes (bulk costs, or something else).

In nature - there's no fixed n:p:k ratio supplied to the plants. So we probably don't have to focus that much on sticking to the same ratios all the time when we just go for weak fertiliser application. Maybe pro growers or display growers will use precise proportions and amounts - which is understandable.

For mixing general fertiliser with kelp solution ... it should be ok to run a trial on a few plants. Just mix and observe the results. If everything looks good for quite a long time, then go with it for the other plants.

[Ray]

Advice about "kelp" usage is kind of nebulous, as there are lots of different kelp-containing products out there, and they're not all the same.

It's along the lines of discussing fertilizer usage without giving the formulas.

What does the label say?

[Orchid Whisperer]

Pretty much all kelp extracts will provide NPK and trace nutrients.

[Ray]

Originally Posted by Orchid Whisperer

Pretty much all kelp extracts will provide NPK and trace nutrients.

Public water supplies often provide nutrients as well, but we don't rate them as fertilizers, do we?