Marie, you could take a look at lechuza pon, it seems to fit your requirements. It's gritty, has slow release fertilizer and comes in 6, 12 and 24 liter bags. If you don't have many plants it could be a good option.

We talked about it a bit in the container and water flow topic if you want to take a look :)

Jo, because I have the gritty ingredients I'd like to be able to use those to work off of, if possible.

Ni Since I only have 2 big doorway pots, I can keep a big watering can with the correct solution and not drag out a hose. I forgot that's what I did towards end of season. (incidently, I must have at least 4 different hose end feeders. I don't know why, but even with rinsing and 'backwashing r' they get clogged up. Also, as one who gardens primarily on land, and not in containers, compost, mulch and long acting ferts...if any....are what I know best)

So, what would be proportions for grit based potting mix for conventional anuuals and perennials pots for summer or fall?

511 or something along those lines is probably best for annuals. I like coconut husk chunks, coir, and perlite. It lasts a good while and doesn't get hydrophobic.

If you are holding stuff for planting out in a nursery bed, why not just put in a little irrigation system? I have all my propagation stuff in nursery containers with gravel and turface and spot spitters. What was the problem with the last go around that those holding planters took too much attention?

Annuals can be in an inexpensive mix that holds water and you just turn out into the compost every year or so. It just ends up being fertilizer and organic matter for the perennial beds.

So far my nursery beds are in full sun. But I have a hose near the part shade growing-on area; All I'd need is a hose splitter to set up a little irrigation system on

a timer. Good idea.

I have planters at my front door, full Florida sun/heat. I use potting mix (MG) and perlite for my annuals. About 1/2 - 1/2. I mulch the surface with wood chips.

Works for me and my plants make it through the heat of summer. I rarely water because I enter my house through the garage and forget the planters. I only use time release with those planters.

Jane

It's not exactly what you're asking, but I made a post covering my sort of 'Soil Mix Calculator' which gives a rough idea how a soil mix will perform: https://www.houzz.com/discussions/porosity-water-holding-capacity-cost-of-common-soil-components-dsvw-vd~4061703

With annuals I would expect you need a lot more Turface so you don't have to constantly water them. Or pick 5:1:1 as Nil suggest or some other mix like Jane has used would be far more convenient.

My experience with CRF are that they are not so consistent in their nutrient delivery. Usually after heavy rains I'll re-fertilize with dissolved powdered or liquid to compensate for the leeching that occurs.

Hi, Marie - You can adjust the water retention of the gritty mix w/o inviting a perched water table that's reluctant to vacate the pot by varying the ratio of screened Turface to grit, while keeping the bark fraction at no more than 1/3 of the o/a volume. For example, you get a lot more water retention by using

4 screened Turface MVP or Allsport

3 screened bark

2 screened grit (Gran-I-Grit in grower size, #2 cherrystone, Manna Pro Poultry grit)

and there is no notable loss of aeration for the change.

If your schedule doesn't allow you to keep up with watering the gritty mix even when it's proportions are adjusted to increase water retention, it really doesn't make sense (from the perspectives of economics and the effort expended to make the soil) to add ingredients that clog the macro-pores that represent the primary reason for making the soil in the first place. If you're going to add ingredients that cause the soil to support perched water, you'd be better served to use a soil you can build for less $ and effort - like the 5:1:1. I wouldn't recommend that you use something like MG + perlite unless the perlite was coarse and represented a VERY large fraction of the medium (like in the 65-75% range). At lower %s, the fine material in the peat-based soils fill all the space between the perlite particles, which means that aeration and drainage are essentially the same as using the MG soil w/o the added perlite.

You can see this in your mind's eye by starting with a quart jar 1/4 full of MG potting mix. Start adding BBs. At what point do the BBs actually improve aeration? Only when there are so many BBs that there isn't enough potting mix to fill all the spaces between the BBs. When the jar still has a mixture of it's original 1/4 MG potting soil + 3/4 BBs to fill the jar, you are finally getting to the point where there is no longer enough MG soil to fill every pore between the BBs. This is called the threshold proportion and it represents the ratio of mixed ingredients at which aeration begins to improve. Follow this link to a PDF file and scroll down to "Media Fundamentals" to read more about why mixing perlite and potting soil in equal measures isn't the answer. What I'm hoping you take from this conversation is, if you want a soil that is well-aerated and drains well, it needs to be BASED on a very large fraction of coarse ingredients that are greater than .1" in size. .1" is not only much larger than the average particle size in soils like MG, it may well be larger than the largest particles in the bag. When you've reviewed the link I provided and familiarized yourself with how the 'threshold proportion' works, you'll see there is nothing, not a single type of material or combination of materials, that can be mixed with MG potting soil in a 1:1 ratio that increases aeration to a notable degree.

Al

I won't even pretend to have read this info carefully- it's midnight here and I have to work tomorrow! I'll say for now I'm not using miracle grow. I find it difficult to re-wet if it gets dried out. Also, I already bought everything for 1-1-1 and today screened the bark and rinsed the turface and grit. I have a half wheelbarrow full of it. A few years ago I was completely taken with the 1-1-1 and 5-1-1 concepts and read most of what I could find here. And I made the 1-1-1 mix, with Mike's help finding ingredients. I didn't keep up the effort, however, in part because I have so few pots it didn't seem worth the effort of procuring the ingredients. As I mentioned elsewhere, one store ten minutes from my house, has everything....my excuses are useless now.

I should certainly be able to get it together enough to water & fertilize the limited number of potted plants I keep over winter, and the few containers I grow in the summer. I was just whining after a very very hot long summer when I could barely keep myself hydrated, much less plants. Its 20 degrees cooler now and my attitude's much improved.

Thanks ewmayo and Al; looking forward to reading your posts more closely over the weekend.

Marie

Hi, M - Without the detailed explanations, I was basically saying there are ways to increase water retention in the gritty mix w/o having to suffer the same limiting PWT present in the soils you left behind for that very reason.

In part, too, my reply was aimed at you and a broader audience that includes anyone else that might read this in the future. Understanding the idea of the "threshold proportion" highlights the futility in trying to amend soils like MG that are limiting due to excessive water retention. Even in FL, TX, SoCal, it's better (for the plant) to use a well-aerated medium that requires more frequent watering than it is to use a medium that holds a significant amount of perched water but allows the planting to go several days between waterings. Geography doesn't eliminate the fact that PWTs are limiting. It can somewhat mitigate HOW limitation PWTs are if conditions are such that water in the PWT is used by the plant or evaporates faster than in other locals, but it still imposes the same limitations in FL as it does in Mn, MA, or MI.

Advice from the grower's perspective can be misleading. If the most important part of growing is limiting the amount of effort it takes, growing in water-retentive soils makes sense on some level; but looking at things from the plant's perspective allows us to realize and forces us to acknowledge what's best for the plant. Only by viewing things from the plant's perspective can we make the kind of decisions we want to make about how much of our plant's potential we want to surrender in order to make things more convenient. No one is judging anyone's decision or saying there is right or wrong to be found when a grower chooses what's convenient over what's best for the plant; only that the grower should realize that the two perspectives more often than not conflict, and it's a good thing to have all the facts in order to make the best decision for ourselves.

I hope you got a good rest, M. ;-)

Al

I'm aware of this.....discussion.....Al and get your point. I really think the answer is a premixed bucket of weak soluable fertilizer kept covered in the shade near the planters is the best solution (ha) for us lazier or overworked gardeners. Get out of car, scoop h20 pour and forget. Said bucket is at hose outlet so it's really brainless

ewwm: thank you....this is very interesting information.I'm sure you spent hours pulling it together as well as the hands on stage. You did what good teachers have always known: experiencial, hands on learning is one of the best teaching and learning tools.

I must have read this thread three times before tonight (or this morning? Yep, I'm an insomniac), but for some reason it didn't click until now. It'll be at least 2018 before the plant needs repotting again, so instead of buying ingredients for 5-1-1, I think I'll call Ewing's in the morning for Turface so I can take the Gritty Mix Plunge for my little emergency project.