Needing Help!

Hi everyone! I'm really new to gardening, I tried last year and only produced 3 small pumpkins but the vines over ran my whole garden.
This year we decided to do raised boxes and only plant what we eat a lot of (or can) well I'm in Northwest Missouri and we had late freezes and bad weather. the only thing I ever started were my tomato plants and the beautiful seedlings are flourishing well but are ready to be put in the ground.
We have horrible soil and I found a recipe for making your own potting soil with equal parts of vermiculite, compost and peat moss so I'm going to drill drainage holes in these huge totes we have and put my tomatoes in there with the homemade potting soil.
I will be near a Lowe's and a Menard's on Monday afternoon and able to pick up the ingredients
My question is if it's a 40lb bag of compost (compost/manure mix) how many 8 qt bags of peat moss and vermiculite will I need to get?

Thank-you in advance for any suggestions you can give me!

Not to rain on your enthusiasm AT ALL, because YAY another gardener, but do yourself a gigantic favor and find a source of vermiculite in 3 or 4 cubic foot bags. You will go broke buying the little bags. The database on the website has local sources, but I just called the local nursery and asked and got a 4cft bag of course for $18 instead of 8qts for $5... can't do the math, but it was HUGE.

I used:
Black Kow
Black Hen
Nutri-Fiber with Bio-Char
aged horse stall leavings (by the truckload)
mushroom compost (by the truckload)

With peat and V. and my garden is outpacing every row garden in the area. Haha!

Welcome to the SFG Forum. I also recommend picking up a copy of the All New Square Foot Gardening book, second edition, by Mel Bartholomew.

Here on this forum we recommend a compost mixture made of 5 different kinds of compost.

Is the bio char actually a compost?

I don't know if bio-char is a compost -- probably not -- but that's the name of the product and since the total mix is FAB, s'OK with me... LOL.

You, know, hats off to Mel. I expected good results, I really did. I looked at the mix and it made sense. I've got compacted gravel and red clay, so I knew I couldn't grow in THAT.

What I did not expect was the WOW I got from all the row farmers who've visited my little garden. And the disgust in their voice when they see my 4-foot tall corn and 6-foot tall toms and the BUCKET of beans I'd just harvested and THEY had just planted a WEEK before. Did Mel proud

Bio-Char made from rice hulls and mixed with other composted vegetation is being used in the Philippines.  I saw some results when I was there almost 2 years ago.  They call it charcoalizing and the resulting material is still recognizable as rice hulls but very easily falls apart and mixes very well.  Seems to serve much the same purpose as vermiculite to keep the heavy compost lighter.

Kay