3:5:3 fertilizer and Phaleanopsis orchids in late fall

[LiveLaughGrowOrchids]

Hello everyone,

I've got a question on fertilizing. The first fertilizer I have is a 3:5:3. The recommended strength is 5 ml per liter and every two weeks. It's marketed as an orchid fertilizer.

Then I've got multifeed, which is for all kinds of plants, it's a19:8:16 and also contains magnesium, zinc, boron, molybdenum, iron manganese and copper.

The 3rd I've got us Seagro which is a fish based thing, 5:0,7:1.7 (53g/kg, 7g/kg,17g/kg) and also contains calcium, magnesium, manganese, iron, copper, zinc and boron.

I've read that you shouldn't fertilize after repot. I've fertilized with nr 1 today, after repotting 2 of my Phals about 5 days ago, and one about 2 weeks ago.

My question is, have I done them any harm?
Should I be fertilizing now, it's late fall,next month will be winter and temps are already dropping.

And also which of the above fertilizers would be best to use, and should I be diluting is further than manufacturing recommendations?

Thanks all!

[WhiteRabbit]

I fertilize Phals regularly year-round, and after repotting.

[RosieC]

I fertilize after repotting and never had a problem.

Fertilisers with the micro-nutrients are meant to be good for orchids, so one of the second two might be best, but the first would also be fine. For years I used one without the micro nutrients and was still happy with the results.

I would use the 3:5:3 at a rate of around 1.6ml/L with every watering.
I would use the 19:8:16 at a rate of around 0.2ml/L with every watering.
I would use the 5:0,7:1.7 at a rate of around 1ml/L with every watering.

This rate is based on current recommendation of 50ppm Nitrogen with every watering (from people I consider experts) and I calculated it using this website.

Nitrogen Management & Calculator | First Rays Orchids

Current thinking is that you fertilise more weakly with every watering, rather than a stronger concentration less regularly. This is more like they would get in nature, just a small amount in the water that does not vary much.

You could use a stronger solution less regularly. The 5ml/L recommendation for the first one is on the end of the scale of the sort of recommendations that were around when I was first taking part in Orchid Board. With that concentration it was recommended to use it once a week, but every fourth week just pour through a lot of plain water instead to wash out the buildup of salts that would accumulate from the fertiliser. Current recommendation is to use it at a lower rate that avoids salt build up and so does not need the regular 'flush' with plain water.

[LiveLaughGrowOrchids]

Thanks! That's really helpful!

[Optimist]

Unless you you blow off the migration of birds and so on, in nature, often there are huge populations of animals in one location, and at other times virtually none. Hence large infrequent doses make sense. In rain forest situations, I think there is less of that moving back and forth. I am not certain though.