Oxheart Giantissimo, 2.294 lbs.

Finally broke two pounds this year!  Just at the setting of August.

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Oxheart Giantissimo (2.294 DT 2012)

This tomato was grown at “Eyreland”, with no thinning, no significant pruning and no other special care.  It’s discovery was a pleasant surprise today!

Flavor was quite good – standard, old-fashioned, and balanced – a bit of sweet, a bit more acidic.  Skin is yellow, rather than clear, however.  Seed source was Nichols Garden Nursery.  There were several other nice-looking ripe tomatoes picked from the same vine.

Brief update on tomatoes I’m tracking –

Big Zac (4.20 Diaz 2011) B-001 has grown just a little over the past few days.  Today’s the first time I noticed distinct ripening coloration.  It now measures to 2.236 lbs.  I will likely harvest it in two days.  Hopefully it will be within 10% of this weight estimate, as that’s the goal of developing the formulas.

Several other of the 58 or so tomatoes/megablooms I’ve been tracking have started to ripen.  Since those are all well under 2 lbs., I went ahead and included them in some agressive thinning of less promising looking green tomatoes – more than four 5-gallon buckets full in the 10 days alone!

For the first time in nearly 3 months there are no 95+ degree days in the 10-day forecast!  Accordingly, tomato vines are setting fruit like crazy.  Excellent for the production tomato plants (~1,300 of them), but a challenge for the competition plants.  I’m seeing an impressive number of megablooms on at least 15 of the 22 plants.  There is barely time to get those to maturity this season, and that’s assuming no frost until the last week of October.  I figure on 60+ days from fruit set to ripe in fall weather, rather than 40 or so during summer heat.

Based on recent growth rates, I project that Church (3.36 Perry 2008) B-001 will be my largest tomato of the season.  But it too looks like it will come in at just under 3 lbs.  Perhaps with the somewhat cooler temperatures I can coax an extra couple of days of growth out of it?  It measures to 2.360 lbs. today.

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Predicting and Estimating Tomato Weights

Well, I finally have a tomato this season which should make it to two pounds.

This fruit has been designated Big Zac (4.20 Diaz 2011) B-001, where:

Big Zac = variety name.  Note that the original Big Zac tomato was a HYBRID.  Consequently, many tomato experts urge using a filial designation (F1, F2, F3, etc.) to indicate then number of generations removed from the F1.  In the world of giant tomato growing, however, selection of seed for saving is made essentially just on fruit size, so there will be (and IS) significant variation among other traits for giant tomatoes grown from Big Zac lineage.  Of course for open pollinated varieties, this variation is much less of an issue.

4.20 = 4.20 lbs., the certified (as is the case with the parent of this tomato) or at least documented (with pictures on reliable scales and with a measuring tape, for example).

Diaz = Julian Diaz of Valparaiso, Indiana, United States of America – the grower of this contest-winning monster.

2011 = The year this tomato was grown.

B-001 = My tracking system, where “B” refers to Phase B of my giant tomato project (i.e., heavy pruning) and 001 refers to the first tomato tracked on this plant.

The parent of this 4.20 Diaz was Big Zac (3.59 Perry 2009).  This in turn was grown from Big Zac (5.32 Timm 2008), but this lineage is not certain.  So the tomato profiled here is probably a Big Zac (F6).

Once this tomato is harvested and weighed, it will receive it’s own designation.  My prediction at this point is:

Big Zac (2.090 DT 2012)

So that is the predicted final weight, once I harvest and weigh the tomato (“DT” refers to Delectation of Tomatoes, although my last name, Thurber, would be entered for official public records).  This prediction is based upon measurements which I’ve been taking, starting on 7-27-2012.

What measurements?  I use vernier calipers and measure to the nearest millimeter (actually I interpolate and record one-tenths of mm, or microns).

So I would record this measurement as 51.7mm.  Why calipers, when most people use tape measures?  1) Speed – depending upon how much vegetation is in the way, one measurement can take 10 seconds or so (I take lots of measurements…);   2) Injury – encircling a growing tomato with a tape measure is risky business – inadvisable unless you’re about ready to pick it anyhow; 3) Durability – this metal instrument has been used thousands of times and is still in excellent condition, though I have to wash it in soap and warm water on occasion.

Our OBJECTIVE is to estimate the weight of a tomato, in grams, based upon measurements taken with either a tape measure or with calipers.  You can convert from metric to English at the very end, if desired.  (Most official weights are recorded in pounds and decimal pounds to 2 or 3 digits).

First, let’s consider measuring CIRCUMFERENCES with a TAPE MEASURE

Which measurements to take?  I take three measurements, in cm, for use in the formula for calculating the volume of an ELLIPSOID.  Let’s orient the tomato first.  Consider the stem end as the top or “North Pole” and the blossom end as the bottom or “South Pole”.  Take three measurements as follows:

1) CC1 = Primary Axis = the longest circumference possible measured through both the stem end and the blossom end (poles) as shown (Scotch tape is very helpful in keeping the tape snug):

So CC1 = 35.9mm

2) CC2 = Vertical Axis = The circumference taken 90° from CC1 as shown:

So CC2 = 28.4

3) CC3 = Minor Axis = Longest circumference around the equator, at right angles to CC1 and CC2:

So CC3 = 37.4mm.

The basic formula for calculating the volume of an ellipsoid is:

V=4/3πabc, where a, b, and c are the 3 perpendicular radii of the ellipsoid.  Since we measured circumferences with the tape measure and CC=2*π*r, we can simplify the formula for this purpose to:

V=0.016887*CC1*CC2*CC3  (in cubic centimeters, or cm^3)

In this example, V=0.016887*35.9*28.4*37.4 = 644 cm^3 (rounded)

This will give you an approximation of the volume of your tomato.  The more bumps, crevices, lobes, fluting and other irregularities on your tomato, the less accurate this formula will be.

So you have the volume.  How do convert this to weight?  If we are talking about pure water, this would be easy, as 1 cm^3 of water weighs 1 gram.  But tomatoes do not have the same density (specific gravity) as water.  I’ve taken density measurements of more than 800 tomatoes (results needs to be published…), so I’ve got a pretty good handle on this variable.

Compared to water, the approximate density of

Green Tomatoes = 0.90

Ripe and ripening (at least 25% ripe) tomatoes = 0.95

These I’ve designated as Density Adjustment Factors (DAF)

Many growers have noted a slight shrinkage of tomatoes as they ripen, so they recommend picking “at first blush”.  I’ve also measured this shrinkage several times, but have found that it is compensated for, at least, by higher fruit density.  So I suggest picking tomatoes when they appear to be at least 25% ripe.  In my experience, measurable shrinkage rarely occurs until tomatoes are at least 80% ripe.

So if you want your prize tomato to be as heavy as possible, harvest it when its approximately 75% ripe in the early morning after a heavy rain or watering.  If your tomato is ripening several days before the big event, pick it when it’s 25-50% ripe and store it at 50-60° with plenty of air circulation and cushioned.  If the tomato is cracked, you might considered treating the wounds with a 10% bleach solution every couple of days.  If cared for properly, competition tomatoes can be stored for up to two weeks.

So, assuming you pick your tomato at 25% or more ripe, the formula for calculating the weight, in grams, of a tomato from measured circumferences becomes:

W(weight)=0.016887*CC1*CC2*CC3*.95 or

W=0.016043*CC1*CC2*CC3 (weight in grams)

For the green tomato shown, we would use 0.90 for the DAF instead, which would be 644*0.90 = 580 g.  Actual weight was 572 g, so accurate to within 2%.  Using this method, we can expect to be within 10% for most tomatoes.  I routinely expect 5-15% lower weights for lobed tomatoes, especially if they are deeply lobed.  Some tomatoes, depending largely upon variety, have some hollowness (air pockets) in their seed locules.  This gives them a “spongy” feeling when gently squeezed, even before they ripen.  So that would be another clue of a lightweight tomato.

Second let’s consider measuring DIAMETERS using CALIPERS

D1 = Length = The longest radius possible measured across the equator, perpendicular to the poles.

D2 = Width = Radius taken 90° from D1, also across the equator.

D3 = Height = Radius taken the blossom end to adjacent to the stem, at right angles to D1 and D2.

Using diameters, measured in cm, and a DAF of 0.95, the formula for Weight grams becomes:

W=0.49742*D1*D2*D3 (weight in grams)

So for the  Big Zac (4.20 Diaz 2011) B-001 pictured at the top, my latest measurements are: D1=16.13, D2=14.48, D3=8.16.  This calculates to 948 g, or 2.090 lb.

This fruit is now at 37 days since fruit set.  It’s growth stopped rather abruptly at 34 days – right on schedule for tomatoes grown during the heat of Summer.  As mentioned elsewhere, 40 days, give or take a couple of days, is what it takes during the summer, at least where I live, for a giant tomato to go from fruit set to time to pick.

I wish I knew a way to extend the growth phase!  Between day 16 and 26, this tomato averaged a 10.3% weight gain per day.  Another 10 days at this rate would have put this one into the 5-lb. range.

So in the next couple of days, I’ll pick this tomato, take final meaurements using a tape measure and see how close this prediction is.  I’m usually a bit disappointed, but this tomato is relatively well behaved, geometrically speaking.

If you take measurements in English units (inches), measure all 3 perpendicular circumferences (CC’s), convert these to decimal inches (i.e. 19-3/8 inches = 19.375 inches) and use this formula, where weight estimate ( W ) is in pounds:

W=0.00056*CC1*CC2*CC3 (weight in pounds)

This uses a DAF of 0.92, so should work reasonably well regardless of stage of ripeness.

For more details about the development of this technique for estimating tomato weights, visit:

Perry’s Greenhouse Tomato Weight Estimation Thread

Giant Tomatoes Growing

Here are the labels of the tomatoes I’m tracking, followed by how much they have grown in the past week.

Big Zac (2.660 DT 2011) A-001              2.02

Gildo Pietroboni (3 Kott 2011) A-001       1.74

Church (3.36 Perry 2008) A-001             1.97

Big Zac (3.94 Pennington 2010) A-001      2.00

Delicious (4.46 Marley 2011) A-001        2.86

Big Zac (5.35 Lyons 2010) A-001           2.32

MegaMarv (5.51 Meisner 2011) A-001        2.80

Brutus Magnum (6.25 Meisner 2011) A-001    4.60

Delicious (6.51 Meisner 2011) A-001       1.74

Big Zac (2.660 DT 2011) B-002             7.22

Big Zac (2.660 DT 2011) B-001            11.28

Hoy (3 Kott 2011) B-001                   3.19

Gildo Pietroboni (3 Kott 2011) B-001     2.99

Church (3.36 Perry 2008) B-001          10.69

Big Zac (3.94 Pennington 2010) B-001    6.50

Big Zac (4.20 Diaz 2011) B-001          2.10

Delicious (4.46 Marley 2011) B-001       2.94

Big Zac (5.35 Lyons 2010) B-001        16.81

MegaMarv (5.51 Meisner 2011) B-001     19.54

For example, MegaMarv (5.51 Meisner 2011) B-001 now measures to 0.36 lbs. and is almost 20 times as large as it was a week ago:

If it could maintain that growth rate for even one more week…

Big Zac (4.20 Diaz 2011) B-001 now measures to 1.12 lbs. and is just over twice as large as last week:

Several other tomatoes have grown rapidly in the past week and are on track to reach 2+ lbs.  But 3 lbs.?  I can only hope…  I applied more compost tea over the weekend.  I think the biggest mistake I’m making is watering with cool, chlorinated culinary water.  It just doesn’t seem like this water would be optimal for the soil microorganisms which break down organic matter and release nutrients to the feeder roots of the tomato vines.  I hope to rectify this issue within the next couple of days.

The most promising new discovery this past week – Delicious (6.51 Meisner 2011) A-002, a 4X+ measuring to 0.33 lb.:

I’ll keep an eye on this one!  If it shows rapid growth over the next few days, I’ll remove the rest of the tomatoes from the plant so more resources can be diverted its growth.  It was buried deep in foliage in the center of the plant and escaped my notice, so I cannot really estimate the date it set fruit.

The candidates

The majority of blossoms are still being lost to hot weather, but fruits from megablooms have set on most of the 22 tomato plants in my giant tomato project.  Since a major objective of this project is to conduct a paired comparison of largest fruit size of tomatoes from Phase 1 (Huge plants – seeds started in late December 2011) to those from Phase 2 (Heavy prune – seeds started on April 20, 2012), I’ll present pics of these candidates in pairs.

I’ve been diligent about keeping plants in Phase 2 pruned to just two stems.  Over the past couple of weeks, I’ve been agressively pruning back new growth on the plants in Phase 1.  With as many as 100+ growing tips per plant when I started pruning, I may never be able to say with confidence that all 11 plants have only 2 growing tips, but that’s what I’m working towards.

So here are the most promising looking tomatoes/blossoms on each of the 22 plants, starting with the smallest parent and progressing to the largest.  Initial measurements were taken on 8-05-2012 and will be continued on a weekly basis as time permits.

Pair 1, Big Zac (2.660 DT 2011):

A: Large plant (now over 7′ tall), a 3X fruit; plant has many 2X and 3X tomatoes.  It will be a challenge to narrow it down to 1. 

B: Heavy prune (to only 2 stems plus a pair of leaves allowed to grow from each sucker), a 3x fruit with a thick peduncle – seems to be growing fast.

A: Large plant (now well over 8′ tall); several fruits have set, but all are singles.  This is a 2X blossom 2.1 m up on the plant – hopefully it will take.

B: Heavy prune; one unbalanced 3X fruit seems to be growing ok – time will tell.

Pair 3, Gildo Pietroboni (~3 Kott 2011):

A: Large plant (now well over 8′ tall); All fruits are hearts from single blossoms.  None appear promising.  Here’s just a representative fruit.

B: Heavy prune – plant is the tallest among 11 in this phase and is pushing 5′ tall; again, all 1X hearts, nothing noteworthy.

Pair 4, Church (3.36 Perry 2008):

A: Large, healthy, aggressively growing plant, over 8′ tall.  Fruits are just starting to set.  This variety has a tendency to produce tightly fused, linear “multi-stigma” blossoms.  It’s sometimes tough to determine how many stigmas and ovaries were involved in producing the fused fruits.  Based on the “navels”, this one appears to be a 3X.

B: Heavy prune – This one is at least a 2X and appears to have the potential to hit 2.5 lbs. or more.

Pair 5, Big Zac (3.94 Pennington 2010):

A: The smallest of the 11 plants in Phase 1, but still nearly 7′ tall – several young fruits show potential; this one’s a double.

B: Heavy prune – this plant is healthy but not yet setting any promising fruits.  Here’s the best one, a single.

Pair 6, Big Zac? (4.20 Diaz 2011):

A: Large plant – As mentioned previously, there was a mixup somewhere along the way and this one’s producing loads of tasty small, red tomatoes.

B: Heavy Prune – this is the first of the 11 plants in Phase 2 to produce a really promising tomato. This is a 4X that set fruit on about July 23rd.  It’s growing at a moderate rate, now measures to 0.52 lbs., and will very likely hit 2 lbs. or more.  Unfortunately, with it’s very flattened shape, I don’t think it has much chance of reaching “giant” status of 5+ lbs.

Pair 7: Delicious (4.46 Marley 2011):

A: Large plant – Judging from the blossom scars (“navels”), this one could have emerged from a 3X or more and appears to have good potential.

B: Heavy Prune – this one also appears to be from a 3X megabloom.

Pair 8: Big Zac (5.35 Lyons 2010):

A: Large plant – Last year this lineage of Big Zac consistently out-performed all other plant in the producing of megablooms and virtually every truss had at least two fused blossoms, with numerous 3X+ blooms.  So far this year, 5.35 Lyons is performing equally well in this regard.  Here’s a 3X that looks almost exactly like my second largest Big Zac from last year, from the 5.35 Lyons, which was certified at 2.510 lb.

B: Heavy Prune – this one’s pretty young still, but appears to be a 3X.

Pair 9: MegaMarv (5.51 Meisner 2011):

A: Large plant – This plant has already produced several ripe 1X tomatoes weighing in at under a lb. Here’s a pic of one that weighed 0.900 lb.

So far, I’ve not seen any megablooms set fruit on this plant.  Here’s a representative 1X fruit on the vine.

B: Heavy Prune – This one is producing perhaps the most exciting and promising fruit I have so far. Even before fruit set I noticed a huge calyx, measuring 9.7 cm (3.8″) across.  A 3X fruit emerged over the weekend:

This fruit seems to be growing very quickly – here’s a pic from a couple of hours ago:

Pair 10: Brutus Magnum (6.25 Meisner 2011):

A: Large plant – This one seems to be very reluctant to set fruit and is showing no recent signs of megablooms.  Here’s the best looking single:

B: Heavy Prune – This one’s also a disappointment so far.  Here’s the best on the plant:

Pair 12: Delicious (6.51 Meisner 2011):

A: Large plant – This plant has not been producing very many megablooms of late, but here’s a flattened 3X that may have potential.

B: Heavy Prune – This is the smallest of the 22 plants and seems to want to send out a bunch of suckers instead of grow tomatoes.  The best I could find was a single blossom:

Obviously it’s too early to draw conclusions, but the plants in Phase B are producing thicker stems and the fruits have thicker pedicles and peduncles.  Logically, a thicker pedicle would have the potential to deliver more water and nutrients to the growing fruit.  Local weighoff date is September 29th.  Perhaps one of these will be competitive by then?

My challenge between now and then is to feed the plants just right so the tomatoes will gain weight very quickly.  So far, I have not figured out how to to that.  What do I feed them; how much and how often?

Bar at 1.356 lb.

Here’s the first tomato of the year to hit 1 pound: Delicious (1.356 DT 2012) from (4.46 Marley 2011):

I’ll let it ripen up for a couple more days before saving seeds and sampling it for taste.

Here are some “blue” tomatoes –

OSU Blue:

Indigo Rose:

“Dancing with Smurfs” – a variety in development by Tom Wagner.  My variant has a nice blueish tinge to the foliage, but unfortunately just a fleck of blue on the skin.  Flavor is pretty good, somewhat sweet but mild:

Here’s a pic of one of my more promising looking varieties as far as size and production, Mémé Beauce: