What's new
TerraForums Venus Flytrap, Nepenthes, Drosera and more talk

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Silly soil supposition

I haven't seen this answered here or in FAQs I've found. So, silly question, when talking about mixing soils, all ratios are given by volume, right? Not by weight? Everything else from houseplants to bonsai, ratios are by dry volume, so I just wanted to make sure.
 
the 3:2:1 ratios you see are by parts. However you want to measure them is up to you.

For example, 3 parts peat, 2 parts sand, 1 part perlite. As long as the measurements are the same style, your good.
 
Well, yes, parts is understood, but mixing sand and peat by parts in volume and mixing sand and peat by parts in weight are two completely different consistencies of mix. For example, a cu. ft. of peat is something like 10 or 20 lbs, whereas a cu. ft. of sand would be closer to 100 lbs. See what I'm getting at? Usually, it's a cup to a cup in a 1:1 ratio, not 8 ounces to 8 ounces. So, by weight, 1 cup of peat might be ½ lb, but 1 cup of sand might be 2½ lbs. By volume it would be a peat:sand ratio of 1:1, but by weight it would be 1:5.
 
I know exactly what you are talking about,
because everything used to be by dry weight all the time.

It seems to no longer be the case, and everything is by simple volume,
and the measurements can be very approximate!
I have mixed up batches that were very different from others,
and everything grew fine. I have even done experimental batches with some
"uncommon" ratios & ingredients, and again, everything works out fine.

A lot of how you base your ratios will need to take your watering habits into consideration.
Less watering needs more peat (or other water holding ingredient), more frequent watering
can use more drainage and hence things like sand, which holds less & drops its moisture faster.

Use common sense and it will all work out fine.
(Seems no one owns a scale any more or is too lazy to weigh things, so volume methods have
replaced the weighing ones. In this case, it doesn't much matter, as there is a lot of flexibility
as far as what works.)

Take care!
:water:

[*As you can perhaps tell, the complexities of actual measuring can be a bit "confusing", hence why the simple volume measuring likely was adopted! I simply think of a pound of feathers and a pound of lead! Perhaps keep this experience in mind when requesting future info and opinions! Amazing! But then now-a-days most people today can't even count back change!]
 
Last edited:
OMG, ROFL on your disclaimer. Ever have this happen? The cashier rings you up at $15.19, you hand them a $20, then realize you have a quarter and don't want to fill your pocket with 81¢, so you say, "wait, I have a quarter". The panicked confusion, especially if they've already rung up and rung in the $20 is so priceless that I sometimes do it on purpose. :-D

FWIW, I know I need ~0.8 cu. ft. dry because it's an 18" hemisphere, so I'll only need maybe a single cu. ft. of peat, and maybe ½ that (I'm thinking) of sand to be more than safe. Things in life can be so much easier if you just would've paid attention in geometry. :-)) "Now when will I ever need to know THAT in real life."
 
Don't be afraid to make more soil than you think you need. I have found that there is always a need for fresh soil.
 
Well, I've gone for more than enough. It made far more sense to go with a full bale from Home Depot than to go with small amounts. The sand I didn't buy enough of to mix 50:50, but I did buy enough to mix twice what I'll need. Thanks for the input guys.
 
Back
Top