Hi,

I am looking for advice on the ongoing rehabbing of my Stromanthe triostar (I call her Rosario).
I got this plant last fall and in hind sight, I realize this was a huge mistake for an inexperienced house plant keeper living in an extremely dry climate.

I put the plant in a corner next to a window and watered and misted it regularly. It did fine for a while, even grew one new leaf, but it totally crashed during the winter. It gradually lost most of its leaves and the rest got brown edges.

After a lot of research, about a month ago I installed a grow light and a small humidifier, so now the plant is likely getting the light and somewhat close to the humidity it needs. I also water regularly with filtered water.

The plant seems to have stabilized, and it is no longer losing any more leaves, however, I have not seen ANY new growth yet. The one positive sign I noted is that it started "praying", meaning its leaves now fold up at night, which it never did before.

My questions are:
1. What else should I be doing for Rosario?
2. How long will it take to see new growth if the plant is on the mend?

The photos show the current set up and condition of the plant.

Thanks!

The plant has been chronically over-watered. I'm assuming, since the plant is in a nursery can, there are drain holes?

Water When the Top Inch or Two of Soil is Dry?
Most growers unfamiliar with how water behaves in container media are prone to repeating the title mantra. But let's look at some facts. A saturated or partially saturated medium is limiting in a number of ways.

Roots need an ample supply of oxygen in order that roots can function normally. Saturated soil surrounding roots limits oxygen required to drive root function, thereby impairing root efficiency and possibly setting the stage for any of a number of fungal pathogens that thrive in anaerobic (airless) conditions.

Soil saturation limits soil gas exchange, so waste gases like methane and CO2 in the root zone are less able to leave the soil, also limiting root function

Soil saturation kills the fine roots that do the lion's share of work involving water uptake and nutrient distribution. When this occurs, chemical messengers tell plant central injury to the root system has occurred. Top growth stops immediately, because root growth always precedes top growth – the top will not grow if the roots cannot support the new growth with water/nutrients. The plant is then forced to regenerate dead roots, using energy which otherwise would have been devoted to additional top growth, keeping the plant's systems orderly, keeping the plant wearing a 'healthy glow', and improving the plant's ability to defend itself. In short, the wasted energy would have kept the plant looking/ growing better, and healthier. This is the tax over-watering levies on plants.

If a pot is 10" deep, the top 2" can feel completely dry to the touch, even while the bottom 6" is 100 saturated. That means 60% of the medium would be fighting you tooth and nail for control over the plant's vitality …… and this is the point at which you should water again? Does that sound reasonable? We don't care even a whit if the top 2" of the soil are dry anyway. Roots there are largely plumbing and anchorage, with essentially none of the fine almost microscopic roots that do the lion's share of the plant's heavy lifting.

Instead of using a digital device (a finger) to 'tell' you when to water, use a real 'tell' instead.

Using a 'tell'
Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant.
Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor.
In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water.
Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'.
One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16" (75-85mm) would work better. They usually come 48" (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue.

I have other suggestions, but I'll wait to see if your thinking has been influenced by what I've said so far.

Al

Hi, many thanks for the quick reply and the suggestion. I am a little surprised to hear that you think it is overwatering, cos I thought watering the plant was the one thing I was doing right... I was suspecting that the issues were with the low light and humidity.

If you look at the photo, the plant sits on a big layer of pebbles in its much smaller original plastic pot inside the larger glazed ceramic cover pot, which sits on a "humidity tray" (it is propped up by larger rocks over water in the tray). Both the plastic pot and the external ceramic pot have large drainage holes.

My research told me that this plants requires high humidity and needs to be on the wetter side, so I water with filtered water about once every 10 days or when the top feels dry-ish, but not fully dry. I was also told to completely flush the plant under the shower once a month - so far I have done this only once. Also, we live in Denver, CO where the air is VERY dry, so for the humidity I have the "humidity tray" underneath and a small humidifier.

When and how often do you recommend watering based on your method for this particular plant?
Also, how long should it take to see new leaves if I'm heading in the right direction?

Thanks again!

If you live in the northern hemisphere, any plant that's stalled during its peak growth period (we're only about 1 month beyond peak) has some serious limitations. The symptoms point to over-watering, but I would have thought a high level of dissolved solids (salts) in the soil solution might have been an exacerbating factor had you not mentioned you flush the soil monthly.

There's no question that the best thing you could do as far as soil choice/watering habits is concerned is start building your own media, and build them so you can't over-water w/o trying really hard. The easiest to make would look like


and consists of:
5 parts pine bark in size dust to 1/2" Most of the product should be in the 1/8 - 3/8" size range
1 part sphagnum peat moss
1 part medium or coarse perlite
a measure of dolomitic (garden) lime appropriate to batch size

I've been using this medium and another with a 2/3 mineral fraction (Turface MVP & crushed granite or cherrystone) for over 30 years, and it's very widely discussed on the internet due to how user friendly and productive they are; they ARE game changers. See here: https://www.google.com/search?...
If making your own isn't in the cards, then doing things to reduce excess water retention and watering judiciously will also be helpful, but not to the degree eliminating all or nearly all of the excess water a medium can hold. For instance, did you know, when the pot has stopped draining after a thorough watering, tipping the pot at a 45* angle will force a significant amount of additional water to exit the pot? Compare B to A in the line drawings below to see how that works. Also note how adding a wick through the drain hole can drain a lot of excess water from containers. Also note how using various forms of ballast (the over-turned pot) will eliminate much of the excess water that severely limits growth, health, appearance of our plants



Setting soil aside for the moment, lets look at what's going on. The excess water in the pot is not only limiting root function, it's killing the finest roots - the plant's workhorses. Limited root function = the roots' inability to effectively move water to the plant's most distal parts - leaf tips and margins, so these are the first tissues to be deprived of water and die. Death of fine roots halts top growth until enough roots regenerate so the plant can again support additional top growth; but, by that point, you're likely watering again and beginning the cycle anew. Using a "tell" allows you to keep abreast of moisture conditions deep in the pot, and you simply withhold water until the tell comes out almost completely dry. If you see wilting before that time, it's undesirable and should be corrected by watering when the tell comes out s lightly more moist.

Any time you have a fraction of the medium saturated, it is robbing the plant of its potential, and that can mean 100% or more of its growth potential. I said more than 100% because growth is a measure of the plant's dry mass. Plants are also shedding organisms and shed parts they cannot support; so, if growth is stalled and leaves are being shed, the plant would be going backward in terms of actual growth - so excess water can sap more than 100% of the growth potential. I'm sure an argument could be mounted from a technical perspective to counter the idea, but the overarching point is still completely valid.

Your thoughts or questions?

Al

Hi, I have a 7 month update on this plant - it has recovered beautifully with regular humidification and the growlight plus watering when the top inch is dry with distilled water only. It stopped growing from Dec-Feb, but as of the last 3-4 weeks it put out 6 new leaves.

How much water are you giving it each time you water it?

kastenariel said: How much water are you giving it each time you water it?

The OP has not participated for more than three years, so I don't think she will respond.
I water this plant thoroughly so water comes out the bottom; in my experience they do not like to get to the dry point.

yeah old post and yeah I do the same.