Watering + root health = elusive ideal?

[m.dlny]

Good day, dear OrchidBoard community,

Today I come with a somewhat philosophical question. Please, bear with me as I give a bit of history to explain myself properly.

Two years ago, I overwatered my orchids wildly and ended up with a fungal problem which lead to black root tips, damping off, and other similar “pleasures”.

After an intensive fungicide treatment, things got better and I got wiser: I reviewed my culture and included bio-fungucide preventives. Roots grew beautifully, but I apparently went too dry because half of my phals grew MUCH shorter leaves (in some cases, a third of the original size!).

Now I am trying to establish the balance between the two extremes and find the balance to keep my plants happily moist, not too wet, letting them dry out just enough, but not too much. But what I have noticed is that when I increase the length of time they stay moist, I still get “unhappy” roots.

In most my pots I have roots with actively growing tips, yet, there are some that are “closed off”. Vegetative growth is ok – as in, it is happening ))) Still in early stages on phals, so too soon to tell whether the leaves will grow larger than the last season.

So, my actual questions are this:

- Is it possible to have 100% of roots in a pot healthy, happy, and actively growing? I mean, in nature plants do not always look their best – not in leaves, nor roots. I've seen plants from experienced orchid growers that did not have healthy looking roots - in some cases, had none at all, even though the plants were blooming beautifully. So, am I striving for an elusive ideal? How many happy - read: actively growing - roots do you normally have in your pots?

- If not, then what is the acceptable ratio of active to “sleeping” roots?

- Are root health and leaves health mutually exclusive to a point? Any tips on finding the balance are much appreciated ))

Many thanks to all who find the time to share their thoughts!

[Ray]

Yes, it is possible - and preferable - to have a nice, healthy root system and keep it that way. The way to achieve that is to find a combination of potting media, containers, and level of attention that suits the needs of the plants, and keep it that way.

Generally speaking, healthy tissue does not rot. If something is stressing the plant, it weakens it, allowing pathogens an opportunity to “go to town”.

Cultural stability is a key here. Consider that the root system grows a cell structure that allows them to function optimally in that environment, and that once they are grown, they cannot change. If the conditions in the environment don’t change, no undue stresses are applied, so the roots stay healthy. If they do, however, whether that be due to changes in the watering, the humidity (affecting drying rate and possibly cooling) ambient temperature, decomposing potting medium, etc., it means the root system is no longer optimized for those new conditions, and they will start to fail, and will need to be replaced by a root system that IS optimal for those new conditions.

[Shadeflower]

Hey dlny,
some good questions. Personally I am happy if I see a few active root tips. Some Cattleya's can fill a pot in one year. Vanda's and Angraecums are much slower to produce as much root mass.

What stands out to me most is the fact that you use the smaller leaves as an indicator of your current conditions (or drier which you have determined was too dry). To me I'd say you managed to find the optimal level of dryness and are now thinking of going the other way again because the leaves have grown smaller.

Yes smaller leaves are an indicator the plant was stressed when it thought about developing that leaf. Like half a year ago. From my limited observations I would even go so far as to say that once a leaf has finished forming and you notice it is smaller then this is not an indication that things are no good at the moment, things could be perfect, the small leaves are an indicator the plant underwent a stressful time one year in the past.

So leaves are an indicator but they are really not the best "current" indicator to use.

I look at the overall color of the roots. Another useful indicator I have come to use recently is to give a dry root a quick spray with a water bottle. A dry root will look like a dry root but depending on how dry it is it will actually behave differently so giving it a quick spritz gives you an indication of how hydrated the root is.
(a bit like testing a battery how full it is). If the root instantly turns green then it is nicely hydrated still.
If it takes 10 seconds to turn green then it is at medium hydration and if water is repelled from the surface like spraying a waxy candle then the root is dehydrated and has started to prevent moisture loss. Roots like these can benefit from a good soak but soaking a well hydrated root even if it looks dry might be too much for it and a light spraying is enough.

[Fairorchids]

Watering (frequency & volume) is not the only factor impacting the health of your plants.

Might temperature range, air circulation and/or light levels be factors too?

[estación seca]

Leaf and growth size are related to water balance. Roots take up water and leaves transpire it to the atmosphere. Inadequate root uptake or excessive leaf transpiration lead to smaller vegetative growths.

Healthy roots depend on all of proper air at the roots, proper temperature, proper moisture and proper ambient humidity. Leaves transpire much more water in a lower humidity environment.

Growths of most orchids in a typical lower humidity home environment are usually smaller than growths in a higher humidity environment.

[Roberta]

My take on this one is "It's all about roots" - if the root system is good, plant health and good flowering follow, since roots are the only way that the plant can take up water and fertilizer minerals. (Fertilizer is "vitamins" - the food comes from photosynthesis, the role of leaves) This is, of course, fairly useless information because it doesn't address the "how to achieve", which is the adventure of orchid growing. Your challenge is to find the best combination of medium and watering frequency for the various plants under YOUR conditions. Confounded by the fact that different types have different needs. So observe your plants and you'll develop the knowledge of what works for you.

[Leafmite]

Watering is probably the most difficult aspect of growing orchids because many of them grow on trees, hanging onto rock or in shallow pockets of soil. The medium (bark, rock, moss, etc.) is there to keep the orchid stable and to provide humidity/anchor to the roots. Air must circulate freely around the roots so that the roots remain healthy.

It is quite a learning curve for those who have grown terrestrial plants in potting soil to grow orchids. I struggled for a couple of years before I discovered lava rock. I could not get the watering right with the bark. I even have better luck with NZ sphagnum moss. I pair both the rock and moss with basket pots. The only orchid that is grown in a different pot is the Phaius but it seems very tolerant.

[m.dlny]

Ray, your comment is educational - as they always are to me ))) Of course, a healthy root system is a goal for me regarding my plants - however, what I want to know, in a healthy root system, will EVERY root be actively growing? In other words, if I have 20 roots in a pot, and 13 are actively growing, but 7 are dormant, does it mean I have a problem with the culture or with a particular plant (i.e. lingering fungal struggles, etc)?

---------- Post added at 01:00 PM ---------- Previous post was at 12:50 PM ----------

Dear Shadeflower,

Thank you for your input )) Yes, indeed, as I have learned (after many failures!) that with orchids many effects are stretched in time - from blooms to problems ))

Originally Posted by Shadeflower

Personally I am happy if I see a few active root tips.

So, do you mean, that not every root in the pot will be active, but a plant can still be healthy and happy? In other words, if not every root is active, it does not mean there is a problem?

And a special "THANK YOU" for your root moisture testing method! I can tell already that I will definitely be using it ))))

---------- Post added at 01:08 PM ---------- Previous post was at 01:00 PM ----------

Kim, I am sure, you are correct as all factors have to be in balance to keep them healthy. For example, we recently had a cold spell, so I could tell that plants stopped growing through it - and adjusted the care accordingly. I suppose, what I am really trying to understand is will a healthy plant have every single root tip actively growing or can a healthy plant also have some dormant root tips, and still be ok?

---------- Post added at 01:10 PM ---------- Previous post was at 01:08 PM ----------

Originally Posted by estación seca

Growths of most orchids in a typical lower humidity home environment are usually smaller than growths in a higher humidity environment.

Estación seca, thank you - as always - for your input. I must say, I am, no doubt, greedy in my wishes - I want to keep them at home, but wish for the plants to grow as if they were in a perfect condition greenhouse (or jungle!)

---------- Post added at 01:17 PM ---------- Previous post was at 01:10 PM ----------

Originally Posted by Roberta

Your challenge is to find the best combination of medium and watering frequency for the various plants under YOUR conditions. Confounded by the fact that different types have different needs. So observe your plants and you'll develop the knowledge of what works for you.

Roberta, a journey of a lifetime, I suppose ))))))

---------- Post added at 01:20 PM ---------- Previous post was at 01:17 PM ----------

Originally Posted by Leafmite

Watering is probably the most difficult aspect of growing orchids...

It is certainly true from my limited experience )) I am glad I did not know this before I got my plants - otherwise I might have been too petrified to even get started

[Roberta]

You'll rarely get 100% active roots in a pot unless you have very few to start with... It's the new roots, that tend to be associated with new growth, that are the best - the ones with active green tips. Then there are the mature ones that may no longer have the green tips, but are fat and firm (depending on the type...some have finer roots) that still has silvery velamin that turns green when you water. Then there are older ones, that may have darker velamin but still are firm. The oldest roots may die. As long as you have a healthy environment in the pot, that's just "force of nature" ... nothing is young forever. <sigh>. On sympodial orchids (the ones with growths that march across the pot) the oldest pseudobulbs may lose leaves and roots, but as long as they are firm they are still contributing to the plant. (Think "fuel tank") So new growth and strong new roots are the clue. For monopodial orchids (one growth point) such as Phalaenopsis, if you get healthy aerial roots but the ones in the pot don't look so good, time to repot - roots need "humid air" rather than "wet".

[SouthPark]

Originally Posted by Roberta

My take on this one is "It's all about roots" - if the root system is good, plant health and good flowering follow, since roots are the only way that the plant can take up water and fertilizer minerals.

It is a good take. My take is ----- provide the particular kind of orchid we grow with suitable growing conditions (media, environment - suitable temperature/humidity/light levels/air-flow, elements (adequate levels of fertiliser and/or mag-cal), treatments - if gets attacked by organisms, appropriate moisture in media etc) --- and the orchid can then grow well ------ leaves, stem, flowers, roots and all.

One approach to maintaining good orchid health is to observe what has (or is) working for relatively long periods of time ----- the way the orchid is grown or being grown (and what treatments are given to it when required).

If it turns out that the orchid consistently does well when moisture levels in the media are within a particular range for some amount of time, and it is then found that the orchid doesn't do so well when the level is kept the same for an extended period of time ------- then just stay with what has worked best.

And then proceed to try find out what might be the issue for the condition where duration 'X' is exceeded at the particular moisture level. The reason might not be known at first. But if some possible answers are later found, then we could proceed to make some tweaks on the growing procedure ----- and could possibly overcome the issue. Or - otherwise, for some cases ----- if it can't be addressed, then sometimes it's necessary to just stay with the plan that works - even at the cost of more time and effort (eg. watering the orchids in a particular way). Or try a different approach.