Interested...

The question isn't, "which mix produces a better plant," but, "which mix produces a better plant for me?"

Some people like a more moisture retentive mix and that works well for them. Some people like better drainage.

NIL13, have you done a side by side comparison of Al's mixes with other mixes?

Nope.

I use different mixes for different purposes.

You could do a side by side comparison, make multiple matrices, control for error and compare two media. All it will tell you is how well plants respond in the differing media based on the methodology used. So if you have a watering protocol of once a month with no added fert and low humidity, the results will say that gritty mix sucks. It always depends on a bunch of factors.

I suspected that you had not done such study. Naturally, the side by side comparison must take into account differences in the fertilization and frequency of watering requirements.

They are certainly much better than 90% of the prepared bagged mixes one is able to acquire! And while this became obvious to me, it was not due to a side by side comparison but rather the marked improvement in plant health and vitality using the prepared bagged mix one year and using Al's mixes (or close approximations) in subsequent years. Didn't need no more persuading than that !! :-)

Actually you would not take into account different watering requirements. That would be two different experiments, unless you want to quadruple the size of the experiment. One with frequent irrigation and one with infrequent irrigation. You only want to test one variable at a time. So if you compare two media everything else must be controlled for. That's why you use matrices and repetition.

So, the answer to my question is that it has not been done.

Vladimir, please read this if you want to know how to compare container media.

http://www.amazon.com/Plant-Production-Containers-Carl-Whitcomb/dp/096131091X

You're asking the wrong question.

I just ordered it. Thank you for the reference.

If you want the ideal medium, you need to know what you need. Do you need a little more moisture retention or maybe it's windy and you need bulk density? Do you want to water once a week or every day maybe 4 times a day? Is maximizing growth the most important factor or is it cost? It's very difficult to authoritatively claim one medium is better than another in every circumstance.

What do you need? If you don't know, start with a recipe and see how that works out for you. If you aren't killing plant, you're not trying hard enough. Just be willing to adapt and try to understand the needs of the plants. There is a lot of science on air space and available water that some people are drawing from.

Maximizing growth is the most important factor.

I would have thought that dealing with your hardiness issue wrt citrus would be your most important factor.

You are going off topic. Maximizing growth is the most important factor in choosing container mix.

Maximizing growth is typically not the most important factor when designing a container medium especially if you have to move the container around. I can't even tell you which medium would provide the maximum growth without knowing all the other cultural factors. It's sort of like asking how to design the fastest engine but not knowing if the engine only needs to last a quarter mile, 500 laps, or 20 years because each scenario yields a different 'fastest engine' with different materials and tolerances. I think at this point we are going in circles though so I'm done.

So coming over from the citrus forum I have additional info... we are looking for info on which would be the best mix to optimize growth and create the healthiest citrus plants possible. Mobility is a factor and we have to move our plants inside in winter. We are in semi cold to cold winter climates with nice summers, ranging from humid to dry outdoor climates. Trees are in containers obviously. We use indoor window light or grow lights or a combination of both in winter.

So we were curious if anyone had actually done any actual trials of the different mixes... I am a believer in 5-1-1 over varied potting soil mix combos as per Al's info and personal experience... but it is interesting that many citrus growers find success using these other mixes- I certainly did not hence I am switching everything to 5-1-1 now. Also I am new to 5-1-1 so I have no idea how it will bear out over the coming winter, but I do have trust in the experiences of other citrus growers in similar climates that it is the best... but I am still interested to see what others may say on this forum.

Nil13, thank you for your replies and
your patience.

no problem

Gritty Mix and 511 aren't as important as the basic ideas behind them. Notice that Al's thread/whatever that introduces both is called "container soils - water movement and retention", not "Al's Gritty Mix and 5-1-1 - a better option". Also notice the actual recipes aren't until the very end and compromise a very small percentage of the words. This thread: http://forums2.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention-xxii?n=493

The basic idea is to use larger particles that hold water inside, and allow air to exist between them. Because of physics (which Al explains in great detail), fine particles tend to hold water in the spaces between the particles, instead of air. This causes the dreaded "perched water table" or PWT (also explained in great detail by Al), which ends up keeping whatever is in the bottom part of the pot pretty much constantly submerged in water, and roots don't tolerate a lack of air. Turns out 1/8" (technically 1/10" according to Al) is the minimum particle size to avoid water being held between the particles (and thus allowing air there).

Following the exact recipes is very useful for beginners, and allows one some amount of confidence that you're doing it right, combined with the actual experience of using a properly designed fast draining mix.

5-1-1 is meant to be easy/quick/cheap to make and designed to be used for relatively temporary situations - annuals, or plants you plan to repot each season.

Gritty Mix (1-1-1) is definitely more labor intensive, but lasts longer, is suitable for longer term plantings, and is more durable and can be reused with a little work.

As Nil3 said, the "ideal" mix depends on many factors, including your enivornment, tools, watering regime, ... making accurate comparisons difficult. But you can find many people who have tried comparisons by searching this forum, and they swing both directions, usually due to grower choices (how it was screened/mixed/watered/fertilized), and not the medium.

So if you use reptibark instead of fines in the 5-1-1 would you say it would last longer than the 1 year before you need to repot?

You could use orchid bark. If you look online you will find orchid bark offered in different sizes. Very small, Small, Medium, Large and chunks. Depends on what you are growing, size of container, and your watering needs. Amazon has many vendors and if you have Prime, no shipping charges.

I live in Florida and mix Miracle Gro, orchid bark and perlite. Offers a good draining mix with some water retention. I choose this mix because it works well for my large container plants. It doesn't dry out quickly as I am not a daily waterer. My plants grow outdoors year round.

I use the Miracle Gro for moisture retention and cost. I grow large trees and I have to be able to move them. Bonsai growing requires more specialized growing than large plants in my opinion. I need some moisture retention.

I am an orchid grower primarily and have hundreds of plants. The temperatures in Florida stress all plants and I have found they must not dry out completely. If you are able to water every day or two, three times a day, use a grit mix. It does not work for me with my lifestyle.

As I advise new orchid growers, you need to be realistic about your watering and fertilizing habits. I do not have the ability to water/fertilize daily. I advise people to be realistic about their lifestyles and the best way to grow healthy plants. I add moisture holding media to my orchids as well. But, I would never recommend that to daily waterers. People have to be realistic and find the best way to grow their plants to fit their lifestyle.

There are so many variables. Growers have to find their own way to make their plants grow well within their lifestyle and growing conditions. It can be done and shouldn't make anyone feel guilty.

Jane

I have not intentionally grown citrus in an inferior mix, but I did grow my Moro in 5-1-1 alongside my pink Eureka in the nursery mix. I missed the optimum re-potting window for the Eureka, and so I thought I would just wait. Nope. The tree started going downhill, becoming more difficult to feed, which resulted in a late-season emergency re-potting in November. I moved the tree into the Gritty Mix and, although it was late in the year, the tree's vitality noticeable began to improve.

I use uncomposted bark only, and this allows my mix to last for many years. I also avoid peat or peat-based potting mix for long-term mixes - I use instead extra turface, or red lava rock, or pumice, as moisture-retaining ingredients.

Josh

Have you tried coir or chc, Josh? I'm quite impressed with how easy they are to wet.

I have not tried either, Nil. I've had such great luck with Greenall Micro Bark, and now E.B. Stone's small sifted Orchid Bark, that I haven't had to look further. I haven't had issues with wetting mixes, thankfully.

Josh

Hi Josh, do you have a thread you can point me to on "optimum re-potting windows" for citrus? I bare rooted & repotted a Eureka that was in the one of the most disgusting soupy nursery mixes two months ago into 5-1-1. The tree sat there doing absolutely nothing, though there were no adverse symptoms, not even transplant shock symptoms. Two months later, I'm starting to see clusters of flowers and the beginnings of new leaf growth. I want to try to avoid seeing my citrus going dormant if I can prevent it.

Also I noticed in your excellent 5-1-1 video tutorial (found channel through another link you posted) that you said you used potting soil instead of peat. Looks like you don't do this anymore? How does your modified 5-1-1 compare to gritty mix? Gritty mix looks like far too much work, especially tracking down the materials.

Sorry if I'm derailing the thread, I wish i could PM you. Hopefully Vladimir will be able to appreciate your answer too.

First Time, there are many, many threads about re-potting windows. For citrus, it is generally advised to re-pot during the Spring, between flushes of growth. In your area, that's probably some time in March or April. Did you resume fertilization two weeks after your re-potted? Fertilization is so important.

Thanks for the compliments on the 5-1-1 video. I still make my mix for peppers and other plants the same way shown in the video, using a quality potting mix instead of straight peat. I typically use Ocean Forest potting mix.

For citrus, I want something that will be more durable and more gritty. So, instead of using potting mix, I use Turface or red lava rock to increase moisture retention. It helps the mix last much longer, although it is heavier and more expensive.

Josh

I replanted a citrus tree and another large house plant in a 5-1-1 similar mix.

Initially they did much better, solved the over watering, wet feet problem.

However over time, the plants started doing poorly because I stopped watering regularly. Couldn't/wouldn't keep up with the daily waterings required in the summer.

So I added a layer of compost to the top and watered it in and then put a layer of wood chips on top to help retain moisture. Plants did much better with a mix that was more closely suited to the cultural environment (infrequent watering, hot weather).

I did a side-by-side comparison of Al's gritty mix and my own mix of peat-based mix with perennial flowering plants.

The peat-based mix did better both years I grew them.

Having said that, I'm a no-maintenance kind of guy. I don't water my plants unless we're in drought conditions. Under those conditions, the peat based mix retained more water and the plant fared better.

If over-watering was my problem or if I wanted more control over when my plants received nutrients and moisture ... I'd go with Al's gritty mix.

For lower maintenance, I think I'd have to go with "regular" potting soil.

My $0.02

@Nil13 made reference to the Whitcomb 311 mix, which is an earlier historical attempt to create a more coarse potting soil for container plants. I think it is extremely helpful to read a document written by Carl Whitcomb that explains how he came on this formula by accident.

Essentially what happened is he accidentally left nine test pots under a bench and everyone forgot they were there. They had successfully nearly killed all of their test plants by watering in a normal potting soil mix and the unwatered plants started to do very well.

What I have started to realize is that any plant can do well in many different soil mixes, if you are able to carefully control the watering. This explains why so many people on this forum claim gritty mix is not as good for their succulents as their (fill in some random horrible soil with lots of small particles) mix. Inevitably those people are growing their plants indoors. They have enormous experience with their plant type and they know exactly when to water the plant. So that is the case of a very skilled gardener compensating for a very bad soil.

What gritty mix does for me is let me grow succulents outside in very abusive weather conditions, without the plant dying. A plant can get a week of rain and it will still drain well. During Summer, gritty mix will tolerate a bit of overwatering, although you still really need to pay attention to not overwatering.

Whether you make your 511 mix with perlite/peat, or with two parts Turface, or with lava and pumice, is probably in the big picture not going to be the deciding factor in whether your plants grow well or not. Success can be add with any of those mixes because the size of the particles allows the roots to breathe and prevents capillary action of water from bring the perched water table to the top of the pot and drowning the roots. Fine-tuning how you make 511 is a question of matching the plant type to the moisture retention of the soil and to the watering habit and climate exposure. Any 511 variant is going to do better than almost any commercial potting soil because of the larger particles used in the majority of the mix.