Hello!
The bark is larger than advised for the gritty mix: 1/8 to 1/4 inch for Fir bark.
The other ingredients should substitute nicely. The only thing that I disliked
about aquarium gravel in the past was the smooth edges. I think sharp grit is better
for holding the mix open and for root-development (drainage, plus root-abrasion).

I am growing a Sedum nussbaumerianum in a small pot in pure screened Turface,
but I also have a pot of Sempervivum growing outside in gritty mix. Semps are great
in this mix.

Josh

Thanks greenman,

I have never heard of that particular sedum before. Looks nice. How did you find it? I did some more investigation and found a site that explains the purpose of the ingredients but it sort of confused me. If the bark and the Turface is for water retention and nutrients then why is the fertilizer needed?

In a timely manner for plants in containers we will still have to water to replace the water the plant took up. Fertilizers are used with the intentions for replacing the food the plant used primarily because ferts food for the plant are limited with in a container growing environment.

Thanks mrlike2u,

If I understand you correctly then the bark and turface are more like extremely slow release sort of nutrient providers? I also wondered about using crushed eggshells instead of gypsum. Is this viable or is the gypsum providing something the egg shells cannot?

Hey!

Bark provides a durable, slightly moisture-retentive filler.
Turface provides much more durability and water-retention, and also holds some nutrients
in its internal structure.

There are virtually no nutrients in the gritty mix, and so the grower must supply
the water and nutrients to the plant. The crushed eggshells are not soluble and will not
provide Calcium.

If you select a fertilizer that provides Calcium and Magnesium, you don't need to add gypsum.

Josh

Hey Greenman,

I am off to get fertilizer! By the way, with your semps in this mix how often do you water? I just started some Semps bareroot from an online nursery and they are outdoors no protection. Do I need to water or should I let the rain do it for me in the winter?

Yep, mine are simply exposed to the rain.
When we have dry periods in the Winter, I do water to keep the mix moist.

Josh

I see you are in N.Cal like me. I am in Tracy. Where are you at?

I'm up in the foothills around Auburn.

Forgot to mention that I received a cutting of the Sedum nussbaumerianum
from a GardenWeb member. Big pots of this Sedum should be available at
your local nursery. During the Summer, it turns a really nice golden color.

Josh