DIY super soil math help

[beckerjeremey29]

Good afternoon Growmies. I'm attempting to make my own super medium, but I'm a little confused. The majority of these recipes out there don't use actual amounts. It's always one part peat and half part bone meal, for example. Now when it comes to peat or soil, they sell them in different quantities. 1.5 cf, 2.8 cf, 3 cf, etc. How do I know what size bag to use? Also, if you use 7.6 cf total of peat, that means each of your amendments has to 3.8 cf of bat guano, for example. Am I missing something? 3.8 cf of each amendment seems like it would scorch a plant. What am I missing? TIA. How do you guys alter recipes to increase/decrease the volume of soil you want to make.

 

[LoveGrowingIt]

I use an old 2-quart saucepan to dole out the parts. So, for example, if a recipe calls for 4 parts soil and 1 part earthworm castings, then I mix 4 saucepans of soil with 1 saucepan of earthworm castings. That usually involves figuring out in advance how much soil mix I'll need.

 

[beckerjeremey29]

I use an old 2-quart saucepan to dole out the parts. So, for example, if a recipe calls for 4 parts soil and 1 part earthworm castings, then I mix 4 saucepans of soil with 1 saucepan of earthworm castings. That usually involves figuring out in advance how much soil mix I'll need.

Thank you. Let's say I'm using 7.6 cf of soil. Now is where the mathematics get difficult for me. Is one part 1.5 cf or the entire 7.6 cf? Or does it not matter?

 

[bgsixxx]

I THINK 1 CU FT = 7 GALLONS

 

[LoveGrowingIt]

Thank you. Let's say I'm using 7.6 cf of soil. Now is where the mathematics get difficult for me. Is one part 1.5 cf or the entire 7.6 cf? Or does it not matter?

If you're using pots for your soil, dry gallons would be a more useful volumetric unit of measure. In that case, there are 6.4 dry gallons in 1 cf. So, there would be 48.64 total dry gallons of soil. For 5-gallon pots and a 4:1 mix of soil with something else, that 48 gallons would fill 12 pots with 4 gallons of soil each, leaving 1 gallon of space in each pot for that something else.

The advantage of using "parts" in recipes is that the size of the part doesn't really matter. Whatever your parts are, they have to be the same size. It could be a quart or gallon or tablespoon.

 

[beckerjeremey29]

If you're using pots for your soil, dry gallons would be a more useful volumetric unit of measure. In that case, there are 6.4 dry gallons in 1 cf. So, there would be 48.64 total dry gallons of soil. For 5-gallon pots and a 4:1 mix of soil with something else, that 48 gallons would fill 12 pots with 4 gallons of soil each, leaving 1 gallon of space in each pot for that something else.

The advantage of using "parts" in recipes is that the size of the part doesn't really matter. Whatever your parts are, they have to be the same size. It could be a quart or gallon or tablespoon.

Thank you! It's making a little more sense to me now.

 

[Natep]

I THINK 1 CU FT = 7 GALLONS

7.5 gallons.

 

[Natep]

When I mix dirt I use a five gallon bucket as a measurement or 1 part. So if I am mixing 30 gallons of soil I would do 2 buckets of peat 2 buckets of pumice 2 buckets of compost. I use craft blend 1/4 cup per gallon. I also add basalt but I just freestyle it.

 

[LoveGrowingIt]

7.5 gallons.

That's for wet measure. I used dry measure because, well, soil isn't a fluid. Here's a screenshot about gallons from Wikipedia:

https://www.google.com/search?q=how+many+dry+gallons+in+a+cubic+foot

 

[beckerjeremey29]

When I mix dirt I use a five gallon bucket as a measurement or 1 part. So if I am mixing 30 gallons of soil I would do 2 buckets of peat 2 buckets of pumice 2 buckets of compost. I use craft blend 1/4 cup per gallon. I also add basalt but I just freestyle it.

Just to clarify, So if recipe called for 1/2 parts bone meal, guano, and kelp meal, you would use 2.5 gallons of each? The math sounds right, but 2.5 gallons of guano, etc. seems like it might be too strong/hot for the plants. Does cooking the soil make it not so hot?

 

[LoveGrowingIt]

Hey @beckerjeremey29 - Let's see that recipe! Please post it.

 

[beckerjeremey29]

Super Soil Mix
The super soil mix is a pre-fertilized soil mix that provides all the nutrients a cannabis plant needs throughout its lifecycle. It's a popular choice among organic growers who want to avoid using chemical fertilizers.

To make a super soil mix, mix the following ingredients:

1 part peat moss
1 part compost
1 part perlite
1 part worm castings
1/2 part bone meal
1/2 part blood meal
1/2 part fish meal
1/2 part kelp meal
1/2 part rock phosphate
This soil mix provides an abundance of nutrients to the cannabis plants, making it a cost-effective option in the long run. It's perfect for cannabis growers who want to maximize the growth and yield of their plants.


This is a good recipe I found on this forum. The only thing that is screwing me up is that they're not giving weights, but parts. I plan on substituting somethings. Like adding lava rocks and rice hulls instead of perlite. Also,
With the amount of peat, I have set up already, it's going to cost me an arm and a leg sourcing the amounts of each amendment. I'm also concerned that the soil may be too hot with 200 lbs. of bat guano in there, etc., even if it is cooked. I don't know how I came up with 200 lbs. for 48.64 gallons of peat. Is my math correct? If not, where did I go wrong? I really appreciate your assistance. Also, if it is indeed possible that my numbers are correct, I may have to lessen the amounts of amendments I add or cut out unnecessary amendments completely.

 

[LoveGrowingIt]

Okay. How much soil do you need?

(For example, four 5-gallon pots would require 20 gallons of soil.)

 

[beckerjeremey29]

Okay. How much soil do you need?

(For example, four 5-gallon pots would require 20 gallons of soil.)

Six 10 gallon pots. I already have 7.6 cf in a 75 gallon plastic bin. It's got a couple of nutrients in it already that I put in myself. I don't want to go to waste, so I want to scale the rest of the amendments to fit with the 48.64 gallons of Peat I already have ready to go. The amount of medium I end up with quite possibly could be more than what I need, but that just means that I have extra for next time. It will give me extra for transplanting purposes and for the next round.

 

[beckerjeremey29]

Okay. How much soil do you need?

(For example, four 5-gallon pots would require 20 gallons of soil.)

I am also considering making a seed starting mix as well, but we'll see what happens. I may just end up buying one. So I don't have to waste anymore time waiting to germinate seeds.

 

[LoveGrowingIt]

Okay. We'll use 60 gallons as the amount of soil to make.

All those "parts" add up to 6.5 total parts.

Let's say that a "part" equals one gallon. If so, this recipe would make 6.5 gallons of soil mixture.

To make 60 gallons, multiply by 6.5 by 10.

10 x 6.5 = 65 gallons (65 is close enough to call it good. Some extra soil can be useful.)

In the recipe, it would look like this:

10 gallons peat moss
10 gallons compost
10 gallons perlite
10 gallons worm castings
5 gallons bone meal
5 gallons blood meal
5 gallons fish meal
5 gallons kelp meal
5 gallons rock phosphate
===================
65 gallons of soil mixture

 

[LoveGrowingIt]

I already have 7.6 cf in a 75 gallon plastic bin. It's got a couple of nutrients in it already that I put in myself. I don't want to go to waste, so I want to scale the rest of the amendments to fit with the 48.64 gallons of Peat I already have ready to go. The amount of medium I end up with quite possibly could be more than what I need, but that just means that I have extra for next time. It will give me extra for transplanting purposes and for the next round.

Considering you only need 10 gallons of peat to make 65 gallons of mixture, you're sure to have enough. That 48.64 gallons of peat is enough to make 316 gallons. Next time, it might be a good idea to figure out the recipe before mixing parts of it together. I don't use peat, so I can't advise about how to use it once it has already been mixed with nutrients. Maybe just store all but 10 gallons of the peat and start with those 10 gallons.

By the way, I recommend using a 5-gallon bucket like those sold at hardware stores to measure your ingredients.

 

[beckerjeremey29]

Considering you only need 10 gallons of peat to make 65 gallons of mixture, you're sure to have enough. That 48.64 gallons of peat is enough to make 316 gallons. Next time, it might be a good idea to figure out the recipe before mixing parts of it together. I don't use peat, so I can't advise about how to use it once it has already been mixed with nutrients. Maybe just store all but 10 gallons of the peat and start with those 10 gallons.

By the way, I recommend using a 5-gallon bucket like those sold at hardware stores to measure your ingredients.

Do you think that 200 lbs. of guano is overkill for a 316 gallon batch of soil? That seems like alot to me.

 

[LoveGrowingIt]

Do you think that 200 lbs. of guano is overkill for a 316 gallon batch of soil? That seems like alot to me.

It seems like a lot, but I don't use guano or grow in the quantities you're planning. You need to think in terms of volume, not weight. Gallons, in this case, are a measure of volume.

 

[beckerjeremey29]

It seems like a lot, but I don't use guano or grow in the quantities you're planning. You need to think in terms of volume, not weight. Gallons, in this case, are a measure of volume.

I understand, but alot of the dry nutrients don't give their product quantities in dry gallons. Take kelp meal for example. The bag I have says 4 lbs. Thank you for all your useful information and help. I really appreciate it.