Hello, I'm from Northern California zone 9A

Hello,
I live in Redwood Valley, CA. One hour north of Santa Rosa, CA.
I love to garden especially square foot. Don't know an awful lot
but I am learning!. Would like to plant fava beans this year. Does anyone
know how many seeds to a square foot. 10 inches deep? I am thinking one seed
to a square?
2nd question. Bought a product called base substrate (expensive!) Put in two bales (4 cu feet) each. I am planning to add Home Depots Patio Plus. What do you think? Did I do good? Haven't added the Patio Plus (I'm afraid to!). So right now I have a 4x4 raised bed with this base substrate in it. It says on the bale that it contains peat moss and, perlite and no fertilizer.
PLEASE ADVISE!!!!! 

 Graygabriel! I am originally from Ukiah, just minutes from you! Do you have the All New Square Foot Gardening book yet? If not, get it as soon as you can. It will give you the details on mixing up your box filler and for the spacing. I have not used the Kellogg before, but make sure you check the full list of ingredients so you can get your ratio right. If it has a lot of peat, you will need to account for that in your blend. There are also plenty of ranches and farms out there - if you know someone who raises some critters, you may be able to score some free manure.

For the Favas, check the spacing on the seed package. If it says 12" spacing, one per square, 6" - 4 per, 4" - 9 per, 3" - 16 per.

What else are you planning besides the Fava Beans?

GG

Gabriel, Welcome to the Forum!   

I second what Goosegirl said. Read the book and you will understand more about the square foot gardening method.

I found that Kellogg products have a lot of peat. So, if you use it, you will have to adjust down the 1/3 fluffed peat part of Mel's Mix.

Thank you both for your speedy response! I thought I would have to wait for a couple of days!! Dug out Mels book and remembered the 1/3 rule! I was a bit confused with the base substrate which is peat moss and perlite. Mel said I can substitute perlite for vermiculite! Hooray! Now I have to dig out 1/3 the base substrate from the box and add the compost. In reading on the web I think Kellogg Patio Plus will be ok for a start. Whenever I plant in the 12" square, I will add one trowel of my home made compost. I have 9 other boxes that have regular garden soil. I have added Platinum Plus to these boxes over the last three years. Would it be better for me to do away with the garden soil and only use the mixture Mel suggests? Is there a big difference in the two? I'll try not to be so lengthy! My husband would be saying "land the plane" right about now!  
Goosegirl, I live off of Black Bart Trail.
I live off Black Bart Trail

Gabriel, I started off using perlite because it was available in large 2-3 cu. ft. bags, therefore affordable. I found bulk vermiculite half way through so the next boxes had a mix. I now use only vermiculite. Bottom line, vermiculite is nicer but perlite will work fine for growing.

Actually, the multi-source compost is the base substrate of Mel's Mix, with the fluffed peat most and vermiculite / perlite mixed with it when first building the boxes. After the first crop is harvested, only the compost is added for the next crop. If you want to be a SFG purist, then only Mel's Mix is used, with compost added over the years.

Do you have 6" of head space left in the boxes? If so, you can put the new MM on top of it. If there's no space left, do you want to remove 6" of the existing box filler and add MM on the top? Do you want to add another 6" layer of wood framing to create the 6" for MM?

I think it is easy for a new gardener to start off as a purist than for an experienced gardener who has existing beds.

If you have other areas to dump the existing bed filling, you can try growing something else in that material. Add rotted manure or compost over it, cover with some wood chips. Look at the Back to Eden topic for non-SFG ideas.

graygabriel wrote:My husband would be saying "land the plane" right about now!  
Goosegirl, I live off of Black Bart Trail.
I live off Black Bart Trail

    Sounds like MY hubby!  

My brother and his family live on Road H!

Having gardened in your area, if you don't have much of a weed problem in those boxes I would recommend just adding one 6" board height to the top of your existing soil boxes and fill that area with Mel's Mix.  Your native soil is very fertile, but unless you have thoroughly amended it, it has a goodly clay content (ACK -the name RED Mountain is a big hint!).  Having the MM on top for a season or 2 will encourage lots of worm activity below in that garden soil to loosen it up more and will give you extra available depth later on for root crops like the bomber carrots my dad and I used to grow.  

One good thing about using the MM - NO ROCKS!!!  I remember sifting the entire garden area of our back yard when I was a kid - to a depth of 12" - to get rid of all the rocks for dad's garden.  We just dumped them over the back fence into the big field behind the house.  About 10 years later, that field was subdivided and a big housing development was put in.  OOPS!!!  Always felt guilty about our poor new neighbor's yard.   

GG

PS - I miss Zone 9A. I am now in Zone 4A!