Dutch Nutrient Formula, Advice?

[Isabella_Rose_C]

Hi Orchid team,

My apologies if there is a thread that has already been posted about this topic. I couldn’t find anything in my first read through, but I may have missed it.

I was wondering if anyone had some opinions and advice on using Dutch Nutrient Formula fertilizers for orchids and if anyone could share some info for me.

Specifically, I am interested in when I start to switch to the bloom formula from the growth and foliage formula. Right now one of my mini Phals are in bloom, but it has been for several months and the blooms are near their end. So should I just fertilize with the growth formula like the either ones not in bloom, or fertilize it differently with the bloom? And if that is the case, should I start the bloom fertilizer formula when the orchids are going to produce a spike in their growing cycle, or wait until the blooms have formed?

As a more basic question, would you water with the fertilizer enriched water (diluted fertilizer in 1 L of water for soil/bark potted orchids), or mist it with the fertilizer rich formula and then water as normal?

Thank you to anyone who posts. And again, if this has already been posted, could you point me to the right forum then? Greatly appreciated.

[Roberta]

Good questions.
First, "bloom booster" fertilizers don't actually do anything to boost flowering. Ray has talked about this in various places. The short description is that excess nitrogen can inhibit blooming, the so-called bloom formulas are simply lower in nitrogen relative to the phosphorus and potassium (the P and K). However, orchids don't use much of either phosphorus or potassium. So to get less nitrogen, the easier solution is just to use less of the regular fertilizer. And once in bloom, the plant should just be treated normally. Spraying fertilizer on the leaves also doesn't do much (except maybe make white hard water spots on the leaves) since orchid leaves have a waxy cuticle (a mechanism to save water in their epiphytic environment), little or nothing is absorbed that way. So for the most part, what is sprayed on the leaves doesn't do anything until it gets washed off and ends up in the medium... where it should have gone in the first place.

[isurus79]

Originally Posted by Roberta

Good questions.
First, "bloom booster" fertilizers don't actually do anything to boost flowering. Ray has talked about this in various places. The short description is that excess nitrogen can inhibit blooming, the so-called bloom formulas are simply lower in nitrogen relative to the phosphorus and potassium (the P and K). However, orchids don't use much of either phosphorus or potassium. So to get less nitrogen, the easier solution is just to use less of the regular fertilizer. And once in bloom, the plant should just be treated normally. Spraying fertilizer on the leaves also doesn't do much (except maybe make white hard water spots on the leaves) since orchid leaves have a waxy cuticle (a mechanism to save water in their epiphytic environment), little or nothing is absorbed that way. So for the most part, what is sprayed on the leaves doesn't do anything until it gets washed off and ends up in the medium... where it should have gone in the first place.

A balanced fertilizer during the growing season and none at all during the dormant season is your best bet. It's also much simpler to keep track of.

[Roberta]

And Phals don't have a dormant season, so they need consistent feeding throughout the year.

[Isabella_Rose_C]

Originally Posted by Roberta

Good questions.
First, "bloom booster" fertilizers don't actually do anything to boost flowering. Ray has talked about this in various places. The short description is that excess nitrogen can inhibit blooming, the so-called bloom formulas are simply lower in nitrogen relative to the phosphorus and potassium (the P and K). However, orchids don't use much of either phosphorus or potassium. So to get less nitrogen, the easier solution is just to use less of the regular fertilizer. And once in bloom, the plant should just be treated normally. Spraying fertilizer on the leaves also doesn't do much (except maybe make white hard water spots on the leaves) since orchid leaves have a waxy cuticle (a mechanism to save water in their epiphytic environment), little or nothing is absorbed that way. So for the most part, what is sprayed on the leaves doesn't do anything until it gets washed off and ends up in the medium... where it should have gone in the first place.

Thank you for this Roberta. Now that you say that I do remember reading about that on Ray’s website, but it didn’t register until about now. The solution of fertilizer is very low based on the dilution, but for my orchids I think I will dilute it even further than the recommended amount.

I appreciate the advice about the leaves. I think I will make the fertilizer solution into a spray bottle and then spray the medium during watering days, so that I know its getting the water it needs but also that I am not overwatering it when I give the water-diluted system.

[Roberta]

In general, rather than spritzing the medium with a small amount of water, it's really better to give the plant a thorough watering (so water runs out of the pot). This does two things - it pulls fresh air into the root zone, and also washes out any fertilizer salts buildup as well as any other "crud". Then, let it partially dry. If you have fresh medium (if you don't, REPOT so you do) it's hard to overwater since the plant dries out more quickly. If you want to get a feel for how fast it dries out, water well, drain, then weight the pot on a postal scale or kitchen scale. Weigh each day, when the rate of decrease of weight starts to flatten out, water again. Once you do this a few times, you'll get a feel for how fast the plant is drying under your conditions. (Don't water by the calendar, water based on the needs of the plant.) You want to aim for a swing from wet to gently damp. As the water evaporates, it's being replaced by air, and humid air in the root zone is your goal.