Productivity will vary greatly from garden to garden but 5-6 plants should be plenty.

Dave

5-6? Yikes, thats not what I wanted to hear!

I was hoping to get away with putting in only 2, maybe 3 plants max. However, putting in 5-6 san marzano plants just to get enough simulaneously ripe tomatoes to make sauce is far too much real estate to commit. I would just as soon scrap them and put in more versatile beefsteaks (rutgers perhaps)

Oh well - thanks for the info...

I used 75 pounds last year for a canner load of thick sauce in half-pint jars.
You need a lot of plants. I don't have enough.
Someday, I'll have a real garden. Like, 1-2 acres!

A canner load? Sorry, I'm planting tomatoes too in hopes of making sauce. :)

It takes a lot of tomatoes to make 1 quart of tomato sauce.

Assuming you want to can it rather than freeze it, that you don't want to waste all the time and energy to can 1 quart at a time, and that you want enough tomatoes ripe at approximately the same time to make it worth the time and effort then yes you need lots of plants. If you only want to make the sauce from 1 variety of tomatoes then you need even more plants of that variety. 5-6 plants is a conservative estimate based on my 40+ years of growing and canning tomatoes.

From the tomato sauce canning guidelines at NCHFP:

Quantity: For thin sauce: An average of 35 pounds is needed per canner load of 7 quarts; an average of 21 pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 10 to 12 quarts of sauce-an average of 5 pounds per quart.
For thick sauce: An average of 46 pounds is needed per canner load of 7 quarts; an average of 28 pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 7 to 9 quarts of sauce-an average of 6 pounds per quart.

Dave

PS: note that most folks can tomato sauce in pints, not quarts.

It depends on what you're calling "tomato sauce" - if you want just plain tomato sauce like you buy in the small cans, pints or even half pints are probably best b/c you're going to use it as an ingredient, not a pasta sauce.

If you're talking "spaghetti sauce" (since you mentioned quarts) then I find 24 oz is the right size for my family of 4 - we like the Chunky Tomato Basil Pasta Sauce from Small Batch Preserving, it can be BWBed (I use the quart time), that calls for 4 lbs to make 8C, I make 1.5 times the recipe so I can get 4 jars at a time but sometimes find that I need 7+ lbs of tomatoes to make it, not 6, of course it depends on how meaty your tomatoes are, I've never used San Marzanos, just beefsteaks. Note this recipe also calls for (commercially canned, though I suppose you could use your own) tomato paste.

I use the freezer method too, Not for sauce but for salsa, kind of the same thing. I just wish I could do it for pickling cucumbers. Last year I had to save those wee suckers up to make a pint and by then the first picked were not ideally fresh anymore. This year: more plants.

Agree totally with digdirt. I usually grow about 10 plants alone just for canning tomato sauce to get through the winter.

gosh, I grow 40-50 plants just to get us all through a year of ketchup. It takes around 8 lbs to make a litre of ketchup, once rendered down to a nice thick sauce. I expect to put up at least 100lbs of tomatoes....and as for stuff like blackcurrants and redcurrants....hours and hours of picking - harvest is the hardest, busiest, most manic time of the year and the kitchen reeks of boiling vinegar.

If you don't want to add tomato paste from an outside source, it takes an absurd number of tomatoes to make sauce. I find it very disheartening.

Even my elderly neighbors, who make and can all of their own sauce, and who have an entire city yard filled with tomato plants, buy their sauce tomatoes by the bushel from a market.

If you freeze the whole tomatoes for an entire season you can save enough for sauce. A good measure for most tomato plants is about 10 pounds a season. If you have 4 plants you could easily save 40 pounds for sauce. Freezing makes skin removal very easy too.