Good Growing Practices - an Overview for Beginners

Hi, Karen. In most cases, I can help growers with suggestions/facts/concepts, based on what I know of the plant sciences and validated by my own personal experience, that will allow them to consistently produce healthy plants. Some growers are already happy with how their plants perform. I'm not interested in trying to talk those growers into making any changes unless they want to, or suggest they SHOULD be doing something another way. If what they are doing is good enough for them, it's good enough for me, too. You might find me debating what course offers the most potential, or how a grower might best direct efforts to achieve a particular end, but I can't tell you what's right for YOU. We know that soils with superior aeration and drainage offer better opportunity for plants to grow as close to their genetic potential as possible, but it's the grower that needs to consider what strategies to implement and which to pass on.

Often, what works or works well, can hinge on a subtlety. For instance, if you use a mixture of MG and composted manure in a conventional way, ie in a pot with a drain hole on a deck railing or over a collection saucer, you might have more water retention than you want or need; but, the same soil/container combination setting on top of the soil in a garden or bed might be an excellent combination because it employs the earth as a giant wick to help drain excess water from the pot. So, if you understand how/why water moves or is retained in soils, you can put that concept to work for yourself instead of having to fight it.

Growing plants to sell might find you looking at that aspect of husbandry with a different perspective than when growing plants over the long term in containers for your own enjoyment. Keeping a plant eternally healthy and happy is different than simply ensuring a plant of saleable size and acceptable health at the point of sale.

I use the gritty mix for long term plantings simply because of its greater potential. I don't mind the fact it requires a little more watering than the 5:1:1 mix, which requires more watering than almost all commercially prepared mixes from a bag. I adjusted my thinking many years ago on this whole watering thing. ;-) The fast-draining soils I use don't require watering too frequently - the more water-retentive soils require watering too INfrequently. If you have an oven with only 2 settings, one is 300* and the other 600*, and the 600* setting won't cook food through w/o burning it on the outside, do you draw the conclusion that 300* is too slow, or 600* is too fast? ;-) Soils are the same way. We might be better off if we judge all soils against those that offer the best potential, but even then we can be certain that our choices will be tempered by how we order our priorities. It does no good to use a high quality soil that requires watering every 3-4 days if you can only set aside the time to water weekly .....

You asked if I was a MG. I took MG training a long time ago, and was a very active member of the local MG's club, along with several other area garden-related clubs/societies, but I sort of lost interest in the MG's club after a few years. Ours just had too much politicking and too many internal control issues going on for my taste. My current interaction with the area MG clubs is limited to the presentations/talks/demonstrations I'm often invited to give and so much enjoy.

Al

That answers a lot, Al. Most of the potted perennials I have for sale are sitting on the ground. I have smaller pots on wooden tables, and some on a plastic table. My containers of annuals are usually sitting on the ground our up on chairs in the gardens, and some are hanging.

I thought you might have had MG training, as you're so knowledgeable. Thanks for taking the time to share your knowledge with those of us who are thirsting for out. I like doing the same. Whenever someone stops by to buy plants, I take them on a tour of the gardens if they show an interest.

Karen

Adding coco-peat to soil for growing pot plants is preferable in hot area as coco-peat can retain a lot of water.

I feel a good plant soil mix is 50% soil+25% vermicompost+25% coco-peat.

Ofcourse for growing xerophytes sand is to be added in desired proportions.

Coir has its inherent problems. It's high pH precludes the use of dolomite as a Ca/Mg source, and it's extremely high K content should be taken into account so adjustments can be made in your fertilizer supplementation program - not the easiest thing to do for the hobbyist when most fertilizers already have adequate amounts of K or more than needed in relationship to N - like all 1:1:1 ratio fertilizers (such as 20-20-20, 14-14-14, etc).

Coir's water retention curve is very close to the same as peat - on a (particle) size for size basis, and it breaks down a little faster than peat. It is also very often very high in soluble salts due to salt water processing. Most commercial enterprises that DO use a fraction of coir in their soils, limit its presence to less than 10% of the o/a volume because of its inherent issues.

Forgive me for disagreeing, but "50% soil+25% vermicompost+25% coco-peat" will yield an exceptionally water-retentive soil - water-retentive in the extreme, in fact. All the particles would be extremely fine, which ensures a very high perched water table (soggy layer at the bottom of the soil after watering well) and problems dealing with it for a very high % of growers. There are much better choices based on materials with a larger particle size.

Al

Hi tapla I guess the coco peat mix (50:25:25) works in Tropics like where we live, the summer temperature can sometimes go to 45 degree Celsius.

If you're happy with the results you get with your choice of soils, that's all that is important. To others, I would note that the list of issues associated with that particular blend of ingredients has nothing to do with geography. Excessive water retention is just that - excessive. It's as excessive in India as it is in Kazakstan or here in Michigan, USA. You may be willing to suffer some of the limiting effects of a soggy soil for the convenience of not having to water so often, but a soggy soil limits plants in India just as it does in Michigan ..... and that's just one of the potential issues - there were several others listed that go beyond the subject of water retention that are valid considerations.

Much depends on perspective. Where you suggest that adding coir to soils where it's hot is preferable - I say that a plant-healthy soil and watering more frequently would be my preferred method of dealing with the heat. Especially since highly aerated soils are capable of keeping roots as much as 15* cooler than their water-retentive counterparts; this, because of the increased evaporative cooling that comes with a well-aerated soil's superior gas exchange.

Al

For me this mix holds good in containers because the water evaporates quite quickly. And again for huge containers or lawns I completely agree with you Tapla, the mix would be soggy.Even in smaller containers depending upon weather I am watering, generally a glass of water everyday. So it all depends.

Okay, Al, I have finally finished reading your thread, and I think I'm understanding it quite well. From what I understand, all my house plants should be repotted around Father's Day, correct? I should just leave them the way they are until then? Not that my plants look bad, really. Most of them look really nice. The only one I'm having trouble with is a recent purchase of about 2 months ago, and Alocasia called 'Stringray'. Nice looking plant, but it's not doing well. Seems the soil is too moist, and it's not drying out. I watered my plants last week, but did not water that one. It is still wet. I do have to pot that on up, as well as another Alocasia and a bird's nest fern. I have 2 of the latter, and I just love them.

Thanks again for all the great info.

Karen

B - lawns aren't usually a problem when using fine soils because they employ the earth as a giant wick, so soils that work perfectly well in the landscape are almost always very poor in a container. Excess water-retention and lack of aeration are the main reasons why, and plants where you live need air in the root zone to function well, as bad as well as plants where I live. Also, large (deeper)containers are much easier to grow in than shallower containers. See the sketch below.

If container 'A' is 12" deep and the PWT after a proper watering is 4" deep, as indicated by the shaded area, 33% of the soil would not drain, leaving 2/3 of the soil w/o perched water. If the container was only 4" deep, the entire soil mass would be saturated after a proper watering, leaving the entire container a saturated mess. Because this saturation impairs root function, ie the plants ability to absorb and move water efficiently, the plant will use the water much more slowly than it would in larger pots. Also, due to the habit of watering in sips (by the glassful), you ensure that ALL the dissolved solids in your irrigation water that aren't used by the plant will remain in the soil, ADDING to the TDS/EC (level of dissolved solids in the soil solution) and making it increasingly difficult for the plant to take up water and the nutrients dissolved in that water.

"It all depends" is a vague term, but in this case we can depend on the fact that soils with a fraction of small particles as large as you're suggesting (100%) are going to present physical barriers to good root and therefore good plant health. From the plant's perspective, it would be MUCH better to use a well-aerated soil and water more frequently than to depend on stacking more water than necessary into the PWT to act as a reserve, because that reserve can ONLY be limiting. From the grower's perspective, it might seem like a good idea because it relieves you from the need to water as frequently as in a healthier soil, but that doesn't change the negative impact on the plant. That the water in a soil evaporates quickly just means that the plant is subjected to limiting conditions for a shorter duration - it doesn't eliminate the negatives associated with a water-logged soil.

I have no stake in how you tend your plants, but I would like others to realize that soils with collectively predominant fractions of fine ingredients are going to be problematic - no matter where you live ..... and that doesn't even address the chemical issues I mentioned that are associated with a large fraction of coir in soils.

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Hi, Karen - There are a few plants commonly grown as houseplants (citrus comes to mind - azalea, too) that might better be repotted earlier in the spring, but the largest fraction by far (prolly 95-98%) would best be repotted in the month prior to their most active growth period. That period between Father's Day and the 4th of July usually finds plants that have some stored energy due to the longer days, and temperatures that allow us to have had our plants outdoors. A lesson taken from bonsai is that trees that are allowed to grow unencumbered by pruning and are bursting with energy will tolerate a lit of indignities their weaker counter-parts won't. Basically what you are doing is tapping into the plant's natural growth cycle and its ebb/flow of energy, and getting the plant's natural rhythms to work FOR you, instead of against you. Lol - that's not some crazzy 'Zen' thing I made up, it's one of the basic tenets of bonsai culture, one that is readily and easily applied to all plants.

There are two gas stations on a road that runs from the bottom of the mountain to the top. If you run out of gas half way up the hill, even 5/8 or 3/4 of the way, and your only option is to push your vehicle to the fueling station, are you going to push it uphill or downhill? Repotting is sort of the same. It might not kill your plants, and you might not even SEE the lost potential, because lost potential is pretty much an intangible, but it is there. When I repot (different than potting up) in the summer, I see evidence of new growth, usually in a week or two after the effort. If I do an emergency repot in the winter, I can usually expect the period between the work and evidence of new growth to be measured in months, instead of weeks. During that recovery period and in that weakened state, the plant is unnecessarily more prone to attack from insects and disease. It just makes good sense to learn to work WITH the plant instead of against it. ;-)

Al



This message was edited Dec 2, 2012 12:24 PM

Sorry - forgot the picture:

Al

Tapla - You are very scientific, the wick explanation is fantastic and made it clear that I am just lazy watering the plants ! and I also got the whole concept wrong.

I was thinking in only one dimension i.e. Large container will need more water and will retain them for a longer time, while small containers need less water and it will be used up/evaporated in a day(in our tropics atleast) so that's why I added coco-peat (ignoring this Root saturation problem as in figure B). Must be the reason why my dad scolds me that I am giving too much water to plants.

By the way please tell me if over-watering makes the leaves more yellow or green or to put it simply how do I ever know if I've over-watered or under-watered a given plant, are there any visible clues?

I am also planning to dilute either some dried cowdung (an let it sit for a day) or Epsom salt in water and apply as a foliar feed (I've come across this new term on internet) is it a good idea?

I have with me right now are Red soil,Coco-peat,Vermicompost,Super phosphate,Dried cow-dung,about 10 gms of Epsom salt and sand (to be gathered from a construction site), considering the above list can you suggest me a mix for Rose plant.

Al, I sure do appreciate all the great information. I now have to gather up all the soil ingredients for this coming summer. I for sure need to repot a couple of Christmas cacti ASAP. I repotted them about a month or so ago, before reading your thread, and I used cactus potting soil, thinking that would be a good thing for them. Well, the soil is holding way too much water for them. I have not watered them in 3 weeks, as the soil is still damp. I'm worried they're going to suffer if I don't get them in a coarser mix soon.

Karen

B - I'm glad for you that you have gained a clearer understanding of the science re PWTs and hopefully how to implement the concept so it works FOR you and your plants. This link

http://davesgarden.com/community/forums/t/1073399/

will explain it in greater detail, if you have an interest. You're being much too hard on yourself by calling yourself lazy, which I'm sure is not the case. Even if you fully understood the concept and chose an extended interval between waterings at the expense of plant vitality, no one should suggest you're lazy. We all order our priorities differently, and none of us knows what's best for you. We can usually speak with a fair degree of certainty about what might be best for the plant, but not the grower.

The symptoms of over-watering are almost exactly the same as under-watering. This is because over-watering also makes it more difficult for the plant to move water to its distal parts, so plants can actually be dying of thirst in a sea of plenty when they are over-watered. Over-watering also makes it more difficult for the plant to take up certain elements under water-logged conditions, so nutritional deficiencies can also be a problem in water-logged soils, even when the supply of nutrients is entirely adequate.

Test your soil by pushing a wood dowel or bamboo skewer deep into your pots. If they come out wet, cool on your inner wrist, or dirty looking, withhold water until the skewer comes out clean - then water THOROUGHLY. If you CAN'T water thoroughly w/o risking root issues, maybe a closer look at your soil's composition is in order.

Foliar feeding is used primarily in agriculture when a crop is growing so fast it cannot get all the nutrition it needs via the primary pathway. Nutrient applications are usually limited to one or two nutrients shown to be deficient by tissue sampling. If you DO see any notable improvement after foliar feeding, it's probably a good indicator there is something wrong with your primary supplementation program. Also, some plants are much better able to absorb nutrients applied to foliage than others - so it's possible in many cases that your efforts might go for naught. You can only gain by foliar feeding if the nutrients you are supplying are indeed deficient in the plant. If there is no deficiency of what you are supplying, there is NO potential for gain - it can only limit.

I don't know what all you have available to you for making soils, but I would suggest that you try something based on larger particles than the possibilities on your list. The two soils I use are shown below.

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Karen - did you review the sketch I posted just above? It shows how tipping the pot or wicking can help eliminate a LOT of excess water. How large is your cactus?

Al

Tapla:- Well well well your soils (2 pics above) look like Kellogs Corn!! I have never seen this sort of soil in my area, not even in the pots of any of our neighbours. By the way in the first pic I could see nice Sunflower seeds if I am right and in the second pic I am not sure why you put a coin (probably seed for a money plant LOL!?)

Now I am about to follow your third link (Water Movement and retention)

And I plant rubber bands as seeds for a unique type of rubber tree, on which tires grow. ;-)

The items on the soils are there only to give some perspective to the size of the soil components. Do you have Seramis available where you live?

Al

Seramis ?? I've never heard of that name and when I search google for Seramis India I am getting suggestions as Ceramics India or Seagrams India !!

I've just searched "Seramis" on google and I am taken to a webpage, probably it's a German company that specializes in Soil products and other tools.

Al, I did not get that before. Thanks for pointing that out. The cactus is not too big, maybe an 8" pot, and one in a 6" pot as well. I will try tipping those, as well as my 2 small Alocasias, which I think are in 6" pots, and are also too wet. I gave them a really good watering a few weeks ago, and they have remained wet. One is not doing so good.

Karen

Tapla: I've learned that raw wood products like Sawdust would not let plants to thrive absorbing all the Nitrogen (that plant roots should feed on) to decompose quickly. Wouldn't such a thing happen when you add fir bark etc,. (as u suggested in your mixes?)

I would think that wouldn't have a problem, as the fertilizers he uses have enough Nitrogen to compensate for that.

Karen

No - there is some N immobilization in all container media, unless it's a completely inorganic mix. Fir bark breaks down very slowly in containers, as does pine bark. That fact, plus their larger size compared to ingredients like peat, compost, coir, sand, topsoil ..... is what makes them so attractive. Sawdust is very fine (texture), and comes from sapwood/heartwood. As such, it lacks the suberin contained in conifer bark. Suberin is a lipid that makes it very difficult for soil organisms to cleave the bark's hydrocarbon chains, which is what gives it its structural stability and makes N immobilization a minor issue. Sawdust has several issues - it's size, N immobilization, heat generated during the composting process which can be considerable, a high pH spike that occurs during composting, and perhaps others that don't immediately come to mind, but what's mentioned should be enough to keep you from considering it as anything but a minute fraction of a soil.

Karen is correct - because container culture is much closer to hydroponics than growing in the earth (maybe 7 or 8 on a scale of 1-10), the N issue can easily be addressed in freely draining soils with frequent applications of fertilizers at low doses. I always reach for fertilizers with an NPK RATIO (different than NPK %s) of 3:1:2. Examples commonly used are 24-8-16, 12-4-8, and what I use - Foliage-Pro 9-3-6.

Al

Hi Tapla, since this sort of pine bark is not available in our area can I use Dried cowdung pieces instead ?

Sorry - decomposition would be too rapid. You want to take steps that relieve you of the effects of perched water, yet still offer good water retention. I think you would be better served if you moved toward the inorganic side .... i.e., if you have complete fertilizer available with all the essential major and minor nutrients. See the second picture I posted on 12/3. Do you have crushed lava available, or something similar to our Haydite? How about doing a search for calcined clay or calcined DE?


Al

Well Tapla, I have none of those, I would try to add some gravel and cowdung pieces and see if I can simulate you mix.

The article I linked you to over at the container forum will always serve you well, as long as you understand the concept and recognize that PWTs are indeed a problem. Here is something I wrote about how to deal with excess water retention in your soils. It should also be helpful:

Dealing with Water-Retentive Soils

A good friend recently asked me if putting a brick in the bottom of a container interferes with drainage? After reading the question, it occurred to me that there are aspects to the question that I’ve discussed very little here @ Dave's. It also occurred to me that I could use her question to help those who grow in heavy (water-retentive) soils. I’m going to define those soils, but this isn’t about disparaging soil types - it’s about helping you try to squeeze the most plant vitality (and the water) out of them. Heavy soils are based on fine ingredients. If the soil contains more than 30-40% of any combination of peat, coir, compost, or other fine ingredients like builders sand or topsoil, it will retain appreciable amounts of perched water and remain soggy after it’s saturated, and this is about dealing with soggy soils.

Perched water is water that remains in the soil after the soil stops draining. If you wet a sponge & hold it by a corner until it stops draining, the water that is forced out of the sponge when you squeeze it is perched water. From the plant’s perspective, perched water is unhealthy because it occupies air spaces that are needed for normal root function and metabolism. The gasses produced under anoxic (airless) conditions (CO2, sulfurous compounds, methane) are also an issue. The main issue though, is that roots deprived of sufficient oxygen begin to die within hours. You don’t actually see this, but the finest, most important roots die first. The plant then has to spend stored energy or current photosynthetic (food production) to regenerate lost roots - an expensive energy outlay that would otherwise have been spent on blooms, fruit, branch extension, increasing biomass, systems maintenance ….. Perhaps the plant would have stored the energy for a winter’s rest and the spring flush of growth instead of expending it on root regeneration.

You can see that perched water, from the plant’s perspective, is not a good thing. From our own perspective, we think it’s rather convenient when we only need to water our plantings every 4-5 days, but because we can’t see it, there is a sacrifice in potential growth/vitality for our convenience - like driving on low tires reduces fuel economy. How we choose to resolve this issue is of no concern to me - we all arrange our priorities & few of us are willing to water plants every hour to squeeze the last wee bit of vitality from them. Growing is about compromise in more cases than not. There is no judgment passed here on soil choice.

If you don’t agree that perched water is generally a bad thing in containers, there’s no need to read on. If you’re still interested, I’ll lay a little groundwork here before I outline some things remedial you can do to combat excess water retention. Almost all out-of-the-bag soils retain a considerable amount of perched water after they have been saturated. Each individual soil formulation will retain a specific height of perched water unique to THAT soil. No matter what the shape or size of the container - height, width, round, square …… the height of the PWT (perched water table) will be the same. You can fill a 1" diameter pipe with a particular soil or a 55 gallon S-shaped drum with the same soil, and both will have exactly the same PWT height.

Let’s do some imagining for the purpose of illustration. Most peat or compost based soils retain in excess of 3 inches of perched water, so lets imagine a soil that retains 3 inches of perched water. Also, imagine a funnel that is 10 inches between the exit hole & the mouth and is filled with soil. Because we are imagining, the mouth is enclosed & has a drain hole in it. In your minds eye, picture the funnel filled with a soil that holds 3 inches of perched water, and the soil is saturated. If the funnel is placed so the large opening, the mouth, is down, you can see the largest possible volume of soil possible when using this container is saturated, the first 3 inches; but, turn the funnel over and what happens? We KNOW that the PWT level is constant at 3 inches, but there is a very large difference in the volume of soil in the lower 3 inches of the funnel after it is placed small end down. This means there is only a small fraction of the volume of perched water in the small-end-down application vs. the large-end-down. When you tip the funnel so the small end is down, all but a small fraction of the perched water runs out the bottom hole as the large water column seeks its 3 inch level in the small volume of soil. In a way, you have employed gravity to help you push the extra water out of the soil.

You haven’t affected the DRAINAGE characteristics of the soil or its level of aeration, but you HAVE affected the o/a water retention of the container. This allows air to return to the soil much faster and greatly reduces any issues associated with excess water retention. OK - we can see that tapered containers will hold a reduced VOLUME of perched water, even when drainage characteristics, aeration, and the actual height of the PWT remain unchanged, but we don’t and won’t all grow in funnels, so lets see how we can apply this information PRACTICALLY to other containers.

Drainage layers don’t work. The soil rests on top of drainage layers, then the water ‘perches’ in the soil above - just as it would if the soil was resting on the container bottom. Drainage layers simply raises the LOCATION where the PWT resides. But what if we put a brick or several bricks on the bottom of the container? Let’s look at that idea, using the soil with the 3inch PWT again. Let’s say the brick is 4x8x3 inches tall, and the container is a rectangle 10x12x12 inches high. The volume of soil occupied by perched water is going to be 10x12x3, or 360 cubic inches. If we add the brick to the bottom of the container so the height of the brick is 3 inches, it reduces the volume of soil that can hold perched water, so for every brick you add (4x8x3=96) you reduce the volume of soil that can hold perched water by 96 cubic inches. If you add 3 bricks, the volume of soil that holds perched water would be 360-288, or only 72 cubic inches, so you have reduced the amount of perched water in the container by 80% ….. quite a feat for a brick.

Your job though, is to be sure that what you add to the bottom of the container to reduce the volume of soil that can hold perched water doesn’t create stress later on when the planting has matured. Be sure the container has a large enough volume of soil to produce plants free from the stress of excessive root constriction. You don’t want to trade one stress for another.

How else might we ‘trick’ the water in the container into leaving? Let’s think about the following in 2 dimensions, because it’s easier to visualize. If you look at the side view of a cylindrical or rectangular container, you see a rectangle, so imagine a cylinder or rectangle 10 inches wide or 10 inches in diameter and 8” deep. Both side views are rectangles. Now, draw a horizontal line 3 inches above the bottom to represent the level of the PWT. Remember, this line will always remain horizontal and 3 inches above the bottom. Now tip the container at a 45 degree angle and notice what happens. The profile is now a triangle with an apex pointing downward and the base is of course the line of the PWT 3 inches above the bottom. Can you see there is a much lower volume of soil in the bottom 3 inches of the triangle than in the bottom 3 inches of the rectangle? The PWT line is level at 3 inches above the apex, so by simply tilting your containers after you water, you can trick a large fraction of the unwanted perched water to exit the container. Sometimes it helps to have a drain hole on the bottom outside edge of the pot, but not always. Only when the location of the hole is above the natural level of the PWT when the pot has been tilted does it affect how much additional water might have been removed.

On the forums, I’ve often talked about wicks, so I’ll just touch on them lightly. If you push a wick through the drain hole and allow it to dangle several inches below the bottom of your container immediately after watering, the wick will ’fool’ the perched water into behaving as though the container was deeper than it actually is. The water will move down the wick, seeking the bottom of the container and will then be pushed off the end of the wick by the additional water moving down behind it.

A variation of the wick, is the pot-in-pot technique, in which you place/nest one container inside another container with several inches of the same soil in the bottom and fill in around the sides. Leaving the drain hole of the top container open allows an unobstructed soil bridge between containers. Water will move downward through the soil bridge from the top container into the bottom container seeking its natural level; so all of the perched water the soil is capable of holding ends up in the bottom container, leaving you with much better aeration in your growing container.

The immediately above example employs the soil in the lower container as a wick, but you can achieve the same results by partially burying containers in the yard or garden, essentially employing the earth as a giant wick. These techniques change the physical dynamics of water movement and retention from the way water normally behaves in containers to the way water behaves in the earth. Essentially, you have turned your containers into mini raised beds, from the perspective of hydrology.

What I shared doesn’t mean it’s a good thing to use water retentive soils, simply because you have tricks to help you deal with them. For years, I’ve been using highly aerated soils and biting the ‘water more often’ bullet because I’ve seen the considerable difference these durable and highly aerated soils make when it comes to plant growth and vitality. Many others have come to the same realization and are freely sharing their thoughts and encouragement all across the forums, so I won’t go into detail about soils here.

It should also be noted that roots are the heart of the plant, and it is impossible to maximize the health and vitality of above-ground parts without first maximizing the health and vitality of roots. Healthy roots also reduce the incidence of disease and insect predation by keeping metabolisms and vitality high so the plant can maximize the production of bio-compounds essential to defense.

The soil/medium is the foundation of every conventional container planting, and plantings are not unlike buildings in that you cannot build much on a weak foundation. A good soil is much easier to grow in, and offers a much wider margin for error for growers across the board, no matter their level of experience. But regardless of what soils you choose, I hope the outline here provides you with some useful strategies if you DO find yourself having to deal with a heavy soil.

I hope that helps.

Al

This PWT and giant Wick examples just stuck in my mind. I will try to use deeper containers atlease from hereon. Thanks a lot.

.... best to you.

Al

Is there a listing of acid loving and non-acid loving plants. I think part of my problem is acidity. After I started using lime (as you suggested), I found a big difference in many of my plants. I use lots of peat moss.

Can you expand a little on your question? more background info?

Al

I never know if a plant is an acid loving plant or not. Should the PH be high or low?

Acid-loving plants prefer a lower pH, but the term 'acid-loving' can be misleading. Some plants are only able to grow in acidic soils because it makes one or more nutrients the plant has difficulty assimilating more soluble and thus easier for the plant to acquire. Or, some plants have trouble limiting uptake of certain elements that are less available under acidic conditions, and need those conditions to limit availability. pH in MINERAL soils, that is in the gardens/beds/landscape, is more important than it is in the highly organic mediums we usually use in containers. If you are able to limit availability of nutrients the plant has a tendency to absorb too much of, or supply the nutrients in soluble form the plant has difficulty assimilating, it hardly matters what the pH of the container medium is. If you supply nutrients in a form that is soluble in the soil solution, and in a ratio favorable to the other nutrients, the plant will have no difficulty with uptake - as long as you keep the roots system healthy.

Al

okay! So I've read most of this thread--at least Tapla's responses :) -- and I still have 2 questions:

1. will the 5:1:1 mix only last for a year? I really don't have the time, space, money to invest in the gritty mix (which from tutorials, seems a bit hard to make, e.g. finding all the materials, sifting, etc.) So, can I do anything to the mix (if, in fact, it only lasts for a year) to make it last longer? Some plants of mine, I think, don't need to be repotted every year necessarily. So, I guess, at most I'd like to get the 5:1:1 mix to last 2 years tops.

2. people seem to complain a lot about the tendency of peat to go hard (so they use coco-peat instead). First, as I see it, I'm not sure why anyone would let their plants go bone dry before watering...But more importantly, is this true? I've never experienced it, and I've also heard that dunking your plant in water for a couple of minutes will help reverse this. What's the consensus?--Is peat hard to use if it dries out?

oh...and one more question :)

is there any reason that 5:1:1 wouldn't work on container plants indoors? I can't quite tell if people are talking about their indoor or outdoor plants sometimes...

1) ..... will the 5:1:1 mix only last for a year? ...... can I do anything to the mix ... to make it last longer? Made well, it should remain structurally sound for at least 2 years or longer. The issue is usually that the plant becomes root-bound to the point it needs repotting before soil collapse becomes an issue. Also, when roots have fully colonized the soil and the plant is fully established, unless you really work at over-watering, soil collapse is less of an issue because the plants roots actually become a part of the soil structure, helping to minimize the impact of a soil that is breaking down..

2. people seem to complain a lot about the tendency of peat to go hard (so they use coco-peat instead). First, as I see it, I'm not sure why anyone would let their plants go bone dry before watering...But more importantly, is this true? I've never experienced it, and I've also heard that dunking your plant in water for a couple of minutes will help reverse this. What's the consensus?--Is peat hard to use if it dries out? Peat and coir both have a tendency to compact and get hard with age. Peat has the additional tendency toward hydrophobia - that is to say, it becomes hard to rewet. I've seen plants (pines) in peat based soils that were so compromised by the soil that the soil was actually harder than the plant's roots, and had to be removed with a chisel. Coir, has some inherent issues that make it unsuitable as a primary fraction of a container soil. It's high pH precludes the use of dolomitic (garden) lime as a liming agent, and it's K content is extremely high, and as such needs accounting for in a fertilizer program if you are looking for best results. Most commercial operations that include coir as a fraction of their container media limit its presence to a small fraction, usually less than 10%.

Dunking your plants in water for an appropriate time (say an hour) can help to more evenly saturate a dry root mass, but it won't reverse compaction.

The gritty mix is my choice for houseplants because it holds little or no perched water, depending on how careful you are about how you make it. The 5:1:1 mix doesn't offer as much potential as the gritty mix under normal conditions, but it still stands head and shoulders above anything you're likely to come across that's base on peat. Also, if you use some of the tricks I've outlined to eliminate all the perched water from the 5:1:1 mix, it should perform almost as well as the gritty mix.

For the most part, getting away from the excess water retention inherent in peat/compost-based soils is going to increase your plant's potential and make it a whole lot easier for you to bring along consistently healthy plants.

Al

This message was edited Jan 7, 2013 10:49 PM

Thank you so much Al! I'm excited about repotting my plants in the spring :)

You say "tricks"--do you mean wicking? I search over this thread again and couldn't find any specifics other than an explanation of perched water as related to particle size. Is it on another thread?

Maybe I can convince my parents to invest in making a gritty mix...And then steal some :)

Thanks again!

Scroll up to my post of 12/5/2 where the title is Dealing with Water Retentive Soils. You'll find lots of tips.

Al

Hi Al, I was reading your comments about repotting vs potting up. Are you saying in your chart that all plants should be repotted every year? Or potted up every year? And if not all plants, how do you know which should be and which shouldn't? Specifically, a variegated Clivia, and also a variegated split leafed Philodendron. I do use Mychlorothiazai sic. on my plants after repotting. Is this not a good idea? Just a boost for their roots. Thanks so much for your help.

Jeanette

I don't want it to be a 'one size fits all' sort of deal, but the growth of plants, and their vitality/health, begins to be affected at about the point where roots become congested to the point where the root/soil mass can be lifted from the pot intact. Some might argue that there are desirable effects attributable to purposely allowing some degree of root congestion, and that is entirely true, but those effects don't negate the fact that there is still a negative impact on growth and vitality.

If you have a plant that you want to bloom more profusely (for some plants), grow more compactly, have smaller leaves/shorter internodes/grow at a reduced rate, SOME root congestion might be desirable; but root congestion from the plant's perspective is never a good thing.

I have hundreds of plants in containers, many of them bonsai and plants growing on as future bonsai, but I also have a number of houseplants/succulents that get fully repotted every 1-5 years, depending on their inherent vigor and growth rate. The increase in growth rate after a full repot/rootwork is easily seen not only by observing the notable increase in growth rate, but in the plant's physiology as well. For instance, I once repotted a Madagascar palm for a friend that had been in the same container for an unknown length of time - well over 5 years, though. Its growth habit was very stout - the plant grew wide, but not very tall. After it was repotted, it doubled it's ht in the first year, and WHEN it was repotted will forever be recorded in the plant's physiology - the spines on the plant before the repot grew very close together (height), after the repot, there was 5-10 times the vertical distance between the spines, indicating the plant was extending at 5-10 times the rate prior to the repot.

Most growers would consider the plant's reaction as a growth spurt, but in reality, it wasn't a 'spurt' at all. It was the result of my eliminating a limiting factor (tight roots) so the plant could return to growing much closer to its genetic potential. We can never make a plant grow at beyond its potential, but we can certainly limit its potential easily enough. What defines us as growers is our ability to recognize and eliminate limiting factors to the greatest degree possible. We can further put our skills on display by using limiting factors to achieve a desired result, but embracing limitations for any reason doesn't negate their effects.

Clivia is one plant that can be potted up until it begins to obviously wane. Rinse all the soil you can from the fleshy roots, then pot up. When the middle of the plant starts to grow weakly, divide the plant, using starts from the outside of the plant mass for your new containers and discard any unneeded plants from the center.

Al

http://www.e-liq.com/

I have finally finished reading your thread, and I think I'm understanding it quite well. From what I understand, all my house plants should be repotted around May, correct? I will leave them until May.:) I just love my plants.

Thanks for the great info.

For most houseplants June would be better, but there are exceptions to the generality. What plants are you considering? and did you catch the fact there is a clear delineation between the significant positives associated with repotting, as opposed to simply potting up? Did you come away from reading the post with the idea that soil choice holds significant sway over the effort:reward quotient?


Al