Water with plain water first before fertilizing?

[K-Sci]

In this post I argue that anything accomplished by watering twice can be achieved by watering with a more dilute fertilizer solution in the first place.

• Pre-watering with water alone means a higher fertilizer concentration will be required to make the same amount of nutrients available to roots.
• Pre-watering with water will result in a gradient where fewer salt ions are present deep in the media but diffusion will equalize the concentrations in hours if not minutes.
• Sphagnum, which can hold huge amounts of water, can easily be over watered by watering twice.

The reason given for pre-watering with water before fertilizing is usually given as preventing root tip burn. I haven't seen root tip burn be a problem even in vanda fertilized at 1Tbs /gallon. This concentration is 8-12 times the amount I normally apply when fertilizing and the salt concentration increases further as drops hanging from vanda root tips evaporate.

So in conclusion I believe that it makes more sense to use a weaker fertilizer solution to start with than to water orchids twice.

-Keith

[Shadeflower]

agreed.
The velamen is like a sponge. If you dip the sponge in one bucket it will quickly absorb the liquid. Once it's full and you move it to a second bucket it won't absorb any more. If the second bucket is your fertilized water it would not be absorbed as much.
The advice varies from water first, then fertilize, fertilize first then flush or like you say use a low amount all the time. The tricky part is knowing how much for each one to use if one wants to use a regular amount as it varies.
If one is not sure then fertilizing first and flushing out any excess shortly after might be a good way.
You could even argue that it might be a better way as the only way of finding what each orchid likes otherwise is through trial and error. But watering twice and flushing each pot is more work than just watering once.

I think to start with fertizling and flushing out the excess is a good approach but as a collection grows and watering time increases it makes more sense to try and figure out how do less watering.

[estación seca]

According to several different ag professors I've heard over the years, for over 50 years commercial agriculture has been watering once with an appropriate fertilizer concentration.

[K-Sci]

Originally Posted by Shadeflower

I think to start with fertizling and flushing out the excess is a good approach but as a collection grows and watering time increases it makes more sense to try and figure out how do less watering.

There seems to be a critical mass for collection size. I think it is likely, particularly for collectors that water indoors in a sink, to burn out on watering and stop watering often enough if one feel they must water twice, once with fresh and once with fertilizer, every time.

-Keith

[Girl_With_An_Orchid]

This is definitely a question I've had. I have always done a quick flush first and then soak in fertilizer for around 20 mins sometimes longer. The only times I don't soak are when its needed but I don't have time so I just do the flush. I think that the soaking allows the sphagnum to absorb enough fertilizer despite having been just watered and also makes sue that the bark doesn't get fully dehydrated. I kind of wonder whether that first flush is even necessary at that point though.

[K-Sci]

Originally Posted by Girl_With_An_Orchid

This is definitely a question I've had. I have always done a quick flush first and then soak in fertilizer for around 20 mins sometimes longer. The only times I don't soak are when its needed but I don't have time so I just do the flush. I think that the soaking allows the sphagnum to absorb enough fertilizer despite having been just watered and also makes sue that the bark doesn't get fully dehydrated. I kind of wonder whether that first flush is even necessary at that point though.

Flushing occasionally is a good idea when watering would otherwise be in too small a quantity to prevent fertilizer and hard water residues from building up in the pot. Flushing before soaking (submerging?) the pot every watering would also remove soluble residues. Unless the soak is in a very tiny amount of water the soluble residues, tannins, and other solubles in the bark will diffuse into the water during the soak and be tossed when the soak is done. Hence the brown coloration of the water. I can't think of anything a rinse and soak would do that either a good rinse or a soak would not already accomplish alone.

That said, when I grew indoors I found soaking for 15 minutes or more did wonders to keep my Phalaenopsis from needing a watering more than once per week (Besgrow bark, no sphagnum). With the much higher humidity in my greenhouse even large chunks of Orchiata are not hard to moisten with drench watering, (after starting them out with daily watering for the first two weeks or so). My orchids in moss would become waterlogged and never dry out if I soaked them once per week.

During my winter schedule I water with RO sprinkling from a water can daily (e.g. vanda with no media) twice weekly (mounts with moss, Neofinetia, & C. Walkeriana in jumbo Orchiata), or weekly (Cattleya and most everything else in LECA and Orchiata). I give all my orchids a good rinse once per month with (almost rock hard) tap water from a garden hose to remove solubles and give them a healthy dose of Ca and Mg.

-Keith

[SouthPark]

I use relatively weak fertiliser - once a month - and have never flushed my pots. And genuinely - the orchids here just keep growing all the same. But ---- for sure ---- considerations need to be made about frequency and concentration applied.

For some of my pots ----- the pots are quite large - and also deep, and there is a lot of scoria inside the pot, and probably a lot of roots too within. What I don't want to do is to super saturate with a flush --- otherwise it could become watery for a really long time down in the dark depths - which could become an issue too. Probably depends on whether some roots can handle the watery conditions or not ------- ie. even if the pot is very good drainage, the volume of media inside my pots can become an issue ----- water-logging. That's why I usually water a particular way - to avoid water-logging.

As for my other pots - shallower ones ----- pretty sure I could flush those ones with no water-logging issues ----- should be ok to do that.

Also - as for semi-hydro/hydro growing ----- as the roots are already used to watery or lower-oxygen environments --- then flushing is usually definitely ok to do.

[Ray]

Originally Posted by SouthPark

Also - as for semi-hydro/hydro growing ----- as the roots are already used to watery or lower-oxygen environments --- then flushing is usually definitely ok to do.

I would argue that in S/H, the roots that have not reached the reservoir are actually in in a more aerated environment.

[SouthPark]

Originally Posted by Ray

I would argue that in S/H, the roots that have not reached the reservoir are actually in in a more aerated environment.

I probably wouldn't need to argue with this case - because the flushing method appears to be generally workable - no issues - with your particular semi-hydro setup. That is - with your set-up, the regions that are quite aerated probably doesn't get water-logged in the way that I might get with my scoria - large/deep pot setup.

What is probably very interesting is the state of the various roots in 'semi-hydro'. Such as - whether the ones up the top start off with being not being adapted - maybe - and then become adapted as they grow further down in the deeper depths.

Also would be extremely interesting to eventually find out whether the roots can be half-and-half ---- such as portions closer to the surface aren't as adapted as the connected portions down deep.

[Fairorchids]

Guys,

Your theory sounds beautiful, but it does not hold water with professional growers.

A. I know of a few, who water with extremely dilute fertilizer solutions in every watering.

B. Most water (drench) with pure water, and fertilize occasionally.

I belong to 'B' group. We water 3 times a week in summer, and gradually scale back to once a week in the middle of winter. Then, after watering, we fertilize with a fairly high dose every 2 weeks (again, reducing dosage in the middle of winter).

With this regimen, I get far better growth results than anyone else I know (hobby or commercial grower).