40/20/20 sounds reasonable. While I was doing the most experimenting with soils and soil ingredients, my focus was on root health. The gritty mix came about almost as a by-product of my search for a soil that held no perched water, but still held enough water in internal pores to satisfy both the plants needs for water and my need to be divorced from having to water with unreasonable frequency. I think the goals are worthy ones, but they can be approached via different routes.

I tend to think of other's attempts at approximating the gritty mix in terms of water/air retention. What would most closely mimic the gritty mix using bark/perlite/Turface, would probably be:
3 bark screened 1/4-1/8
4 perlite screened over insect screen
2 Turface screened over insect screen

You know better than I, what you're trying to achieve. I try to leave you with the idea that the air:water ratio and durability is important; and the hundreds of forum discussions help to show what roles the physical properties of various ingredients you might use play. The CONCEPT is the important thing. How you get there doesn't matter much. Have fun & let us know what your experiences are.

Best luck.

Al

Thanks you for the direction. It's finally starting to look like fall here, after weeks of nice dry weather, it's raining for the next few days. Next week when it is dry again I'll start playing with the new mix.

How do you decide if it is necessary to add lime or gypsum to the mix? I know you has lime in your basic recipe, but you mention that gypsum may be necessary. I know lime will lower the PH, but am not sure how to determine when this is necessary. Can you point me to a discussion that get more in dept with when to use lime vs gypsum?

Thanks again,

Jamie

Lime raises pH. Generally speaking, soils with a low starting pH can afford the rise in pH lime causes. That would be the 5:1:1 mix, which has a starting pH of 4.5-5.0, pre-lime. The gritty mix has a higher starting pH and lower buffering capacity, so lime isn't appropriate. If you're using a fertilizer that doesn't contain Ca, then gypsum is the best choice as a Ca source. If the fertilizer also contains no Mg, then Epsom salts is a good source.

I've gone all summer using Foliage-Pro 9-3-6 with several plants in the gritty mix that had no Ca source added, and they're fine. It's very probable, that when you're using the FP 9-3-6, that neither gypsum nor Epsom salts are required for Ca/Mg.

Al

Hello;

I am not familiar with Foliage-Pro 9-3-6. On my Bonsai, I used something called Bonsai Pro for a while. Then I asked on the Bonsai forum about it and some really experienced people told me that any fertilizer is fine and the expensive bottle of Bonsai Pro is just a scam.

In the soil mixes I have made in the past, if I include a fertilizer, I use a professional general purpose 14-14-14 controlled release fertilizer similar to osomocote.

As a water soluble, I use Nutriculture 20-20-20.

Are these the wrong things to be using for container gardening? Is there an advantage to switching to FP?

Thanks

Jamie

See if the link I'm leaving answers your questions, Jamie. If not, just come back and ask any you might have. Foliage-Pro is a top quality fertilizer. The only bad thing I can say about it is the low NPK%, but I'm assuming that is because they are using CaNO3 (the only soluble form of Ca) as a Ca source and they need the extra water to keep the Ca in solution. Most other soluble fertilizers do not contain either Ca or Mg, but FP has them both in a favorable ratio. Many of us prefer 3:1:2 ratio fertilizers like 24-8-16, 12-4-8 and 9-3-6 because they supply nutrients in a ratio very close to that which plants actually use.

Al

Here is a link that might be useful: Read about it here

Thank You. Your old posts have answers a lot of my questions. Jamie

You can always ask the ones that DIDN'T get answered. ;o)

Al

AL;

I do have a quick question. Would it hurt anything to put some granite (say #2 grit) in the bottom of my nursery pots?

The reason I ask is because most of my nursery pots have 4 holes on the side and one on the bottom and I have to use a larger piece of screen to cover the holes, and it likes to slip out of place (and dump tuface everywhere). I think putting in a inch of stones on top of the screen would help anchor the screen in place. Since grit is so free draining would that cause any problems?

Thanks

Jamie