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East Carbon, Utah

For those who don't mind a doing a bit of math and who are a bit on the obsessive side (I'm probably not the only one here?) -

I've compiled data from 135 large to giant tomatoes and developed a polynomial formula for estimating the weight of your tomato while it is still on the vine based on a single measurement: Widest circumference (CC).

This is usually measured around the equator with the stem being the pole. Though for the "horseshoe" shaped tomatoes, this would of course be around the widest dimension.

W = 2.9221 - 0.3876CC + 0.0193CC^2

Where W = Weight, output in pounds and decimal pounds
CC = Circumference, input in inches and decimal inches

The R^2 for this formula is 0.9420, so there is a fair amount of slop (how can there not be with such bizarre shaped tomatoes??). Basically if you have a very flat tomato, this formula will likely overestimate substantially. If you have a very "tall" tomato, it will underestimate. Deeply lobed tomatoes or those with big gaps will also be overestimated. But at least this should get you in the ballpark.

Tomatoes from 1.09 to 8.41 lbs. are included as inputs. Many thanks to a number of other growers who provided numbers for development of this formula - Gritch (Julian) in particular has provided many numbers over the past couple of years.

This formula is not fixed in stone!! Would love to have more data for input to fine tune it.

Mostly need:
1. Final weight
2. CC

Also helpful:
3. Variety name
4. Lineage
5. Grower name
6. Where grown
7. Date of harvest

9/11/2014 7:10:26 PM

East Carbon, Utah

Here is an example for my largest tomato, which is still on the vine!

CC = 23.9

W = 2.9221 – (0.3876X23.9) + (0.0193X23.9X23.9)

W = 2.9221 – 9.2636 + 11.0244

W = 4.68 lbs. projected

But since this Domingo tomato is VERY flat, it will likely end up on the 4.0 – 4.2 lb. range. Might get a couple more days of growth out of it, however.

Also have a formula for estimating weights on CC’s in all three dimensions. That one’s more accurate but is more involved. Contact me for details.

9/11/2014 7:10:34 PM

East Carbon, Utah

Got 6 more days of decent growth, a gain of about 0.24 lb.

Final CC for this tomato was 24.4, so this formula yields an estimate of 4.96 lbs.

Harvested today:

Domingo (4.647 DT 2014)(4.55 Wahl 2012)

9/17/2014 8:32:06 PM

France

I noticed the formula estimation is often over estimating a little bit. I bet It depends of the shape, a regular shape will be ok but a ugly multi ones won't be accurate. I have sent you 3 dimensions of all my best tomatoes for 3 years in a row now to help the formula.
That would be very helpfull if we could get more and more data ! come on !

9/18/2014 3:48:12 AM