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Need to convert inches to gallons

I'm trying to figure out what Pot size to transplant my Trinidad Moruga Scorpion into, and my local nursery only labels in inches. I know I want something between 3 and 5 gallons. The biggest they have is 14x14.

What is the correct formula to use to convert length x width into the inside gallon capacity?
 
1 gallon is 231 cubic inches. Volume of a cylinder is V=pi*r^2*h, a pot will hold more than an actual cylinder due to the tapering at the top but that's way more difficult to calculate. Or if the top is 14" but the base is narrower it will hold less. I'm going with 14" at the base.

So for a 14" x 14" pot you would have V=3.14*7^2*14 = 2154 cubic inches +/- the additional volume from it not being a true cylinder.

2154/231 = 9.32 so somewhere around roughly 10 gallons.

Also found this which lists typical pot sizes vs gallon equivalents but no idea how accurate the info is:
http://www.hardytropicals.org/blog/entry/pot_sizes_inches_to_gallon_conversion

4" pot= pint (0.5 quart)
5-6" pot = quart (0.25 gallon)
7-8" pot= 1 gallon
8.5" pot = 2 gallon
10" pot = 3 gallon
12" pot = 5 gallon
14" pot= 7 gallon
16" pot= 10 gallon
18" pot = 15 gallon
24" pot = 25 gal

30" pot= 30 gal
 
If your pot is square you don't need all of that Pi stuff and it's a piece of cake....

Length x Width x Depth = Cubic Inches
Cubic Inches x .004329 = Gallons
or
1 Gallon = 231 cubic inches

If it's 14x14x14....
14x14x14=2744 Cubic Inches
2744/231= 11.8 gallons
 
No need to get all technical - though you can, if you want. Go to your local hardware store, and take a peek at their buckets. A standard orange Home Depot bucket is 5 gallons. Get a pot roughly the same size as one of those.

Oh, but if you REALLY want to get technical, consider that all round, tapered pots would eventually form a cone if the sides were extended from the base down. Figure out how tall the pot would have to be to form a perfect cone, then use the cone volume formula to calculate the volume at the base (which would be the part of the cone without the pot), then the same formula to calculate the volume to the top (which would be the entire cone, including the pot.) Subtract the two, and you have the volume for the pot.
 
Typically, I have seen 5gal containers be 14", and 10gal be 18"-20". 5gal is plenty big enough for pepper plants, unless you are trying to overwinter and grow a super plant.
 
Something else to keep in mind is that there is no standard of measurement between pot manufacturers. What one company calls a gallon pot may be very different from what another company calls the same thing. Unfortunately, the same is true with pots measured in inches. A 10-inch pot with a steep taper is going to hold less than a 10-inch pot with a gentle taper. Also, where they measure the 10 inches may not be the same - at the rim or some other point? This can make a big difference, too.
 
No need to get all technical - though you can, if you want. Go to your local hardware store, and take a peek at their buckets. A standard orange Home Depot bucket is 5 gallons. Get a pot roughly the same size as one of those.

Oh, but if you REALLY want to get technical, consider that all round, tapered pots would eventually form a cone if the sides were extended from the base down. Figure out how tall the pot would have to be to form a perfect cone, then use the cone volume formula to calculate the volume at the base (which would be the part of the cone without the pot), then the same formula to calculate the volume to the top (which would be the entire cone, including the pot.) Subtract the two, and you have the volume for the pot.

I am really, really, bad at geometry and your technical part is way over my head.

Thanks for the advice about the Home Depot 5 Gallon Bucket. I can get one for $2.78. Much cheaper than the $25.00 my local florist charges for the 14x14 clay pot. The only issue I see is that I would need to cut a hole in the bottom - unless somebody tells me that this is not necessary. Is it bad practice (I assume it is) to use a bucket without bottom drainage? G - what tool would I need to cut a circular hole in the bottom of that thing.

Also - for the 5 Gallon Bucket - How much soil do I need to fill it?
 
Even better - start checking out the garden section at Walmart. They have pots that are not terribly expensive and already have holes drilled. The kind I got has coasters that snap off - pull those off before putting dirt into the pots.
 
need to convert inches...... that's what she said

Agree with all of the above....3-5 gallon bucket should do. Look on the bottom
 
But the green ones are "Green".

Healthier plants, healthier soil, healthier environment.

Just be sure to rinse the enamel paint out with Lacquer thinner first.
 
If your pot is square you don't need all of that Pi stuff and it's a piece of cake....

Length x Width x Depth = Cubic Inches
Cubic Inches x .004329 = Gallons
or
1 Gallon = 231 cubic inches

If it's 14x14x14....
14x14x14=2744 Cubic Inches
2744/231= 11.8 gallons


This is a good guideline, but it looks like it wil get a little complicated with nursery pots as they are narrow on the bottom, then increasingly get wider as it gets closer to the top.
 
You guys are bad!

Seriously, drago, here's a link to my grow thread from a couple seasons ago. You can see the pots I got from Walmart, of several different sizes. Used the same pots last year, and unless I ripped up the bottoms too much by dragging them around on the cement, will reuse them this year, too.
 
G - Thanks as always.

I've got a home depot a few blocks from where I work and can pick up a 5 gal bucket. The problem is that I am one of these geeky types who can't hammer a nail straight, so unless I bother a friend, it will be hard for me to get holes on the bottom. With the pics of the 5 gal buckets and your grog pics, I have a good guideline on what size to get. Unless I figure something else out, I'll pick up something appropriate (smaller than the 14x14) at my local nursery tomorrow.

I'm starting my main grow next weekend - I'll be trying to sprout around 20 non-superhots that will go in the garden at the end of May. I intend on having the Moruga Scorpion transplanted into the final pot before then, so It will be easier for me to position the lighting
 
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