How much medium will I need?

[HeyMrDeej]

Hi everyone,
I’m planning to repot about 15 of my parent’s neglected cymbidiums once they finish flowering and I was wondering how much medium would I need to get.

I’ve been eyeing Flori-culture’s coarse orchiata mix, but I can’t grasp the idea of how many 10x10 pots a 1 cu ft would fill. Also since cymbidiums are semi terrestrial would it be better if I got a medium grade mix instead of the coarse grade?

Thank you.

[Ray]

10 x 10 x (height) = cubic inches per pot. 1 cubic foot is 1728 cubic inches, so if you assume the root mass will take up 50% of the volume, you'll need:

0.5 x 15 x (100 x H) / 1728 = cubic feet, or simplifying it, just divide the height of the pot (in inches) by 2.3.

What particular medium is going to depend more upon your growing conditions and watering habits.

[HeyMrDeej]

Ahhh thank you for the help to figure out how much I’ll need.

I’m from SF, CA so I think my conditions are somewhat cool/intermediate. They currently reside under a shaded balcony, get a couple hours of direct eastern light then shade the rest of the day, and get watered probably every 2 weeks depending on the season.

[Paphluvr]

HeyMrDeej,

Are you talking about square pots or round pots? Ray's numbers are good if the pots are square but if you're using 10" Radius x 10" Deep round pots you'll only need about 3/4ths the amount you would need in the square pots.

[HeyMrDeej]

I’ll be using round pots.

[Roberta]

For Cyms, I get seedling bark - relatively cheap. A 2 cubic ft. bag. I also mix in some #2 perlite (I don't measure, aim for something like 1 part perlite to 3 parts bark by volume, but I'm totally not precise. Don't waste fancy Orchiata on Cyms... they don't need it. This mix stays on the damp side, and that is what Cyms like.

As far as where to get it... I don't know but with all the orchid growers in the SF Bay area, I am sure that you can find a nursery that has orchid supplies. If a Google search doesn't find what you're looking for, you might contact the San Francisco Orchid Society. Their website just lists the membership chair membership@orchidsanfrancisco.org but if that person can't answer your question, will be able to help you find someone who can. (By the way, it is a marvelous club, and meets monthly on Zoom ... I live in southern California, but have joined SFOS and "attend" meetings quite regularly... distance melts away...)

[HeyMrDeej]

Thank you for that detailed answer. I’ll def keep googling and check out Amazon.

[Roberta]

Originally Posted by HeyMrDeej

Thank you for that detailed answer. I’ll def keep googling and check out Amazon.

If you can find a nursery supply place that has the bark anywhere near where you are, it's worth driving over there... shipping will likely cost you more than the bark itself. That's why if a Google search doesn't find what you're looking for, draw on local knowledge... SFOS has something 300+ members, I think, and a whole lot of them grow Cyms. To say nothing of the other orchid clubs down the Peninsula and east Bay. So I can almost guarantee that someplace near you carries it.

If you can't find a local source, Flori-Culture is near Sacramento, so the distance isn't large which should help to control shipping cost (or even still be in range for a pick-up)

[HeyMrDeej]

I was already looking at flori-culture for the medium but you’re right. I went on Facebook and checked out the sforchid society and currently reaching out to - few members/sellers where they get their supplies.
Thank you again.

[Orchidtinkerer]

I work in liters - for my biggest pots I need roughly 3-4 liters of substrate which I think yours are with circumference of 25 cm

So 15 x 4liters = 1x 60l bag, if they sell it in 50l sizes that might just be enough.