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CIRCULAR NO. 447| end of fi le, OCTOBER 1937 =
UNITED STATES DEPARTMENT OF AGRICULTURE ||hm
WASHINGTON D.C .

THE FREEZING TEMPERATURES OF SOME FRUITS,
VEGETABLES, AND FLORISTS’ STOCKS ~~

By R. C. Wriaut, physiologist, Division of Fruit a Vegetable Crops and, Diseases,

Bureau of Plant Industry ee | al
{| kU”
=i @
CONTENTS
Page ;

Isrtroduction: sf Cesta he eee Eh Aer ee ee 1, Freezing points of fruits—Continued.

HMreezing) Points oltruits: pe se ee 3 Miscellaneous fruits... -. 2.22222. 2.25. _- 7
TANG Oy OLS spate al Nt hing msl ee nek Maradona 3 | Freezing points of vegetables _______-________- 7
CHEGEIGS SAT Sie ee SEEN ee eee T SS 5 Potatoes eet e: Seed by eee Ree ey ee 8
Ga PeS te eee eee ieee bees were ret et 6 Sweet potatoes 242: eee eae 8
Oran ceses sie Mas te Paes ee ees ve ae 6 OMATOCS 2 sae ee SA NA eed 8
Peaches-_ ___---.-_-- ie Sire aS re tee BO 6 SWEGLiCONMS oes. Sete ol ek PN ee 8
FETE Roh = ae a ara ce eS a ee a 6 Miscellaneous vegetables________________- 8
SES Se RS eed ee, ee 6 | Freezing points of florists’ stocks_ ___________- 8
SUELAWiDCLHICS teen eee arte meee eed ae eee I CHES UMM a Tye oS ee Ree ae aa eect ae 10
Blackberries, raspberries, and cranberries 6 pe

INTRODUCTION

There is an ever-increasing demand from persons interested in the
growing, shipping, and handling of produce for exact data on the
freezing points, or the temperatures at which actual ice formation
takes place in various products.

The extent of damage due to the freezing of produce in transit
naturally varies from year to year, but it is usually very heavy,
aggregating frequently several hundred thousand dollars during a year.
This in general applies not only to such products as apples and pota-
toes, most of which are grown in the North and harvested and shipped
in the late fall and winter, but to products that are grown in the South
and Southwest during the winter and shipped to northern markets.
This latter group includes citrus fruits, strawberries, tomatoes, lettuce,
string beans, cabbage, cauliflower, eggplant, etc. Cars of these food
products often leave the shipping point under refrigeration and in 24
to 86 hours may pass into a zone of freezing temperatures. As they
approach the more northern markets they may be exposed to tempera-
tures ranging several degrees below their freezing point. Under
certain conditions when harvested in warm weather some of these
products are precooled—that is, rapidly cooled to a refrigerating
temperature, either immediately before or directly after they are
placed in the car for shipment, in order to delay maturity and conse-
quent deterioration. Where precooling is practiced, it is, of course,
essential to know the temperatures to which the product can be
lowered with absolute safety.

1 This circular is a revision of and supersedes Department Bulletin 1133, The Freezing Temperatures of
Some Fruits, Vegetables, and Cut Flowers.

1221°—37 1

9 CIRCULAR 447, U. S. DEPARTMENT OF AGRICULTURE

It is of great importance to the commercial cold-storage man to
know the exact freezing points of the fruits and vegetables which he
handles. In some instances established commercial-storage practices
have been changed after the exact freezing points of certain products
have been ascertained. In most cases fruits and vegetables, other
than dried or prepared products, when placed in cold storage are
alive, and the problem is to keep them alive and healthy throughout
their storage period. Since various fruits and vegetables freeze at
different temperatures, there is more or less doubt in the minds of
those interested as to the proper and safe temperatures at which to
hold them in storage. One of the problems in the storage of many
products is to hold them at a temperature low enough to slow down
the life processes in order to prolong their storage life and yet not allow
them to be damaged by actual freezing, which of course is likely to
injure their keeping qualities or market value. With many products
this storage temperature is only 1° or 2° above the actual freezing
point. Of course some products, such as cherries, strawberries, peas,
and lima beans. may be purposely kept in a frozen condition below
freezing temperature, but this subject comes under the head of freezing
storage and will not be discussed here.

It should be borne in mind, however. that freezing or freezing injury
does not always occur when fruit or vegetable products are exposed to
temperatures at or below their true freezing points. This is shown
in the studies on potatoes reported in a previous publication,? where
tubers were cooled as much as 10° F beiow their freezing points
without actually having become frozen and were again warmed up
without apparent injury. The commonly known fact that some
kinds of products may be actually frozen and then thawed out under
certain conditions with no apparent injurious effects constitutes fur-
ther evidence on this point. On the other band, certain commodities
such as tomatoes, bananas, and cucumbers are definitelv injured if
stored at temperatures many degrees above their actual freezing
points. This is usually termed chilling injury. It is evident. there-
fore. that temperatures just above the freezing point cannot be
regarded as safe for all types or varieties of fruits and vegetables.
It is also noticeable that there are variations in the freezing points of
fruits and vegetables of the same variety and from the same lot, as is
shown in the tables that follow. Furthermore, it is quite probable
that different individuals of the same variety and strain when grown
under different conditions will have somewhat different average
freezing points. Attention is therefore called to the fact that the
freezing points given in the following tables should be considered as
danger points; that i is, at or near these temperatures, either above or
below them. there is ‘danger of injury by freezing if exposed for a
sufficient length of time.

It has been found in some cases, as has been pointed out, that the
freezing points of some varieties are liable to slight variations. These
variations, however, are probably of more importance in the study of
the exact causes and results of freezing injury than from the point of
viev of the commercial cold-storage and produce man, for the varia-
tion of a fraction of a degree hardly warrants any change in the treat-
rient of the product.

Wricut, R. C., and TayLtor, G. F. FREEZING INJURY TO POTATOES WHEN UNDERCOOLED. U. S.
Dept. Agr. Bull. 916. 15 pp., illus. 1921.

FREEZING TEMPERATURES 3

The determinations of the freezing points of most of the commercial
varieties of fruits, vegetables, and other plant materials have been
made by the Bureau of Plant Industry in connection with its cold-
storage investigations. ‘This work is being continued.

Except where noted, the products reported upon were American
erown and harvested at the usual state of maturity for commercial
marketing. The method of determining freezing points has been
described elsewhere.’

FREEZING POINTS OF FRUITS

Where several varieties of one kind of fruit were investigated the
results are given separately to allow comparisions between varieties.
The results are given in table 1. In table 2 these are summarized,
and in addition there are listed the results of freezing-point determina-
tions on a number of other fruits where only one representative variety

of a kind was studied.
APPLES

Freezing-point determinations were made on a number of varieties
of summer or early apples and of fall and winter varieties, most of the
eastern-grown varieties being produced on the Arlington Experiment
Farm, Arlington, Va. The tabulated results by varieties (table 1)
show considerable varietal differences among both summer and
winter apples. The average of all summer varieties is practically the
same as that of winter varieties, the former being 28.4° while the latter
is 28.5° F. There is very little difference shown between the freezing
points of eastern-grown and western-grown fruit.

TABLE 1.—Average and extreme freezing points of different varieties of certain frurts

| |
Extremes | Extremes
Kind, variety, state of matu- |Aver-|———_————_ Kind variety, state of matu- | Aver- 7 |e
rity, and place where grown age iy pee MES rity, and place where grown age | ini-|Maxi-
mum| mum mum |mum
Apples, summer varieties, east- Apples, fall and winter varie- |
er-grown: ET eS PS 1G tee De ties, western-grown: SDE Orde eh OR
Yellow Transparent__--_-_ 27.7 Hit lee Oe Deliciouset8 2 28.4 | 28.0 | 28.9
Red Astrachan___-_._-____ 28502) 2852 |) 26 Gano tae eee ee 28.5 | 28.3 | 29.0
HM ATVOR IPS ss =e 29, 2}. 28.81) 29:5 Grimes-Golden=_2__-_-- 28.3 | 29.0
28a PASE T sy = Oe ee 29.6 | 29.3] 29.7 JONAEAAN See 28.3 | 28.0] 28.7
SCHWelLZer=ae weee t De a: |e Dino) acted: HOMOrBeaUiya--o- a eeee 28.9 | 28.7 | 29.4
shoemaker se 3 as 28.5 | 27.9 | 28.0 Esopus Spitzenburg--.--__- 28.7 | 28.3 | 29.0
IBenOniee ee 28.8 | 28.5 29.0 WiineSapiose sees eres nae 2852 |) ote 9 23.3
Early Joe-------.---------- 27.8 | 27.6 | 28.5 FR Se nnn 98.5 | 28.2| 28.9
pples, crab: ——— _——————
Average_----------------- | 28.4 | 28.1 | 28.6 Marthaioe._-.\ 22da02 .(at 26.7 | 26.6} 26.8
Apples, fall and winter varie- | Transcendent-_------------ 27.5 27.2 28. 2
ties, eastern-grown: ARV CT: AD Ot Te Fn Lane ee QTL 26393|- 2755
Bela wine Sets 29.0 | 28.8 | 29.4 || Blackberries: ——
3G Dany ke eee 29.6 | 28.2] 29.0 Harlystarvest: _--2=2--2- = 28a p2eioa|| o 2850
Dealicigns’s fe 2. ae 28.5 | 28.2! 29.1 Juiihost tnd eecans tak | 59.1 | 28.7] 29.3
Grimes Golden___-.-----__ 29.0 | 28.8! 29.0 Mldorados 52) 2. |B 29N eoeesal “2005
Jonathan ase! ee ZONE ote Onlleeone: Crystalwiite! == eae 28.4 | 28.1 28.6
AZ AT AU OMe eae ee EE a 28.5 | 28.4:] 28.5 Logan (loganberry) -------_- 29.5 | 29.3 | 29.7
HATO es eee ss tera ee 28.5 | 28.3 | 28.9 || Cherries, sour, mature, eastern-
Stayman Winesap-_----_-__ 28.5 | 28.0] 28.9 grown:
VV STAC AyD Be bo he = alee: 28.2 | 27.9 | 28.7 Early Richmond_-_-_-__------ 2AO | 28: hk 28.3
Yellow Newtown_-_--_------ 28.0 | 27.8] 28.2 Montmorency...-.------_- 28.1 | 27.8 | : 28.6
Work Imperial. = 2-2: s.—- 2 28.3 | 28.1] 28.5 Stpiviedardas2= 2s See 28.1 | 27.6 | 28.6
AL CT AOR E ws = Boe ke a 28.5 | 28.2] 28.8 ALVOLAG i528 2 te a See pr 28.0 | 27.7) 28.3
Se

i
i

3 TAYLOR, G. F. SOME IMPROVEMENTS ON THE NEEDLE TYPE THERMOCOUPLE FOR LOW-TEMPERATURE
WORK. Jour. Indus. and Engin. Chem. 12 797-798, illus. 1920.

WRIGHT, R. C., and HaRVEY, R.B. THE FREEZING POINT OF POTATOES AS DETERMINED BY THE THERMO-
ELECTRICMETHOD. U.S. Dept. Agr. Bull. 895, 7pp.,illus. 1921.

WRIGHT, R.C.,and Taylor, G. F. See footnote 2.

CIRCULAR 447, U. S. DEPARTMENT OF AGRICULTURE

TasBLeE 1.—Average and exireme freezing points of different varieties of ceriain

jruits—Continued
| | |
| | Extremes || |
Kind, variety, state of matu- | Aver-| ; | Kind, variety, state of matu- | Aver-
ity, and place where grown | age | Tone Roe || ity, and place where grown age
} num) mum
Cherries, sweet, mature, east- | fennel European or vinifera
ern-cTrown: SR | oR [oR type—Continued. oR.
Core ye = a 24.9 | 23.9 25.8 || Henab Turki, South Africa_| 26.1
Mary fall 222s 2 24.5 | 24.5} 24.6 || Rasin Blane, South Africa, 24.9
| | Prune de Cazouls, South |
PA worse ous 353 2 2s | 24.7 | 242] 25.2 || Afloat tn Sa Bg | 26.4
i Barlinka, South Africa_____| 25.6
Cherries, sweet, California: | \] Waltham Cross, South Af- |
Black Tartarian, mature___| 24.2 | 23.5 | 25.1 || Ls oo eee | 25.5
Black Tartarian ,immature_| 25.8 | 25.4} 26.6 ||
Bing, mature____--.....__- 24.1 | 23-4) 24:3 ]i Average, Mature:
Bing, immature____________} 25.3 | 24.6} 26.4 || alifornia__________ 24.8
Sypeanni S85) ee ee | 25.6
Average, Mature_________ |} 242) 23.5) 247 Argentmsa-- ______ 23. 2
Average, immature______ | 25.6 | 25.0} 26.5 || South Africa_______ 25.8
Cranberries:! || Oranges:
Searl, Wisconsin__________- 28.2 | 27.9| 24 Washington Navel, Cali- | | |
Gebhart Beauty, Wisconsin_ 26.3 | 26.0] 26.9 ornia:
Mammoth, Wisconsin_____ | 26.7 | 26.4) 269 A Ej "oh WEES AS Reet he Shs Te } 28.4 |
Metallic Bell, Wisconsin___| 25.6 | 2£8) 25.8 | Ring #22 ti a sa Ee | 27.4
Chipman, Massachusetts__| 26.9 | 26.0! 27.4 1] Valencia, California, flesh_| 27.0
Perry Red, Massachusetts_| 27.9 | 26.61 28.0 || Pineapple, Florida, flesh___| 27.7
Early Black, Massachw- | {| Seedling, Florida, flesh____ | 28.2
oi 3 16e $15 Sys aes Seas Oe | 28.1} 27.6) 287 || Temple, Florida, flesh_____ | 28.6 |
McFarlin, Massachusetts__| 29.0 | 28.4| 29.4 | Valencia, Florida: |
Shaw Success, Massachu- 1] ‘Blesh <2) 2
Setts 2/6 27 fe SR OO 25.0 | 246| 25.7 Binder, eis ene TEE 27.4 |
Howes, Massachusetts__.__| 28.2 | 27.5 | 28.4
Pride, Massachusetts______ 27.0 | 26.6 | 27.7 Average:
Wales Henry, Massachu- Blesly yest 2eee 23.0 |
oo Se ee ae 23.7 | 27.9) 23.0 }| 133717) ba a aes | 27.4 |
| | 1
A Verano 27.3 | 26.7} 27.6 || Peaches, hard ripe |
I} A | acta ete eS ARE rer 29.8 |
Grapes: American or euviiis || Pineria Oe eee 227 |
type: Stevens < 2020 0) 4 Sees | 28.6
Bol Concord |} 28.4] 27.9] 287] mdvemant. 2.) 2 NoLe | 29.4 |
PMO is ae eee } 28.2} 27.8} 28.6 || A211 1 1 ee ee ree 29.6 |
Dracut Amber_____._-.-__- | 27.9 | 27.8} 28.1 | Bilyen 2... aa ee 28.9
Moore ‘Early -=>__ = 28.3 | 28.1} 23.6 |) pe) 11 i, he ae a aes = 29.3
@Ripenwaiie 2 bs | 27.9 | 27.1}; 220} alweye 2. 2862 ae | 29.6
Campbell Early___________ | 28.0 | 27.8 | 28.0) lay +S. nee | 30.0
IMerieadelas fee a | 28.5 | 28.4) 28.5] Carmmank 3 Sip tee See 29. 6
Crea =F acu = Caeee “aaa | 27.3 | 27.2} 27.4 | Champion_-- - ee | 29.1 |
Cainwha22 2a este } 26.7 | 26.2) 27.7 | Bart Hosels= 2s ae 28.5
Coneurd 9 22 8S 8 AEDES eo dE bale 2 eee 29.6
Delhnwaree 2 2£6 | 24.2) 25.4
a IAVERAGO eh 28 ee 29.4 |
LQG a: Se ee 27.5 | 27-2) 27.8 |
Pears:
fae European or vinifera | Bartlett, hard ripe________- | 28.5 }
3 Bartlett, soft ripe__________ | 27.8
— (Almeria), mature, | Beurre Bose, hard ripe_____ 27.8
Calilgenige: 320222 ee | 25.6 | 25.2} 26.1 Anjou, hard ripe___________ 26.9
Ohanez (Almeria), mature, | | Anjou, soft ripe____________ 27-2)
Spano ee | 25.6 | 24.6) 26.7 Kieffer, hard ripe__________ | 27.9 |
Ohanez ee imma- | | Kieffer, soft ripe. .________- 28.1 |
hires Spain} 2s ee. 25) SR a7 2 Winter Nelis, hard ripe____| 27.2 |
Ohanez “(aimeris), mature, | Winter Nelis, soft ripe_____ | 27.5 }
V5 i353 1) 311) Se ee ene) Oe Ae (id aN) a ;
Ohanez (Almeria), Mature, | Average, hard ripe_______ 20.7 |
South Ames. 2 25.8) 253) 26.4 Average, soft ripe________| 27.7
Emperor, California__...._} 24.6 | 241} 248 :
Emperor, Argentina_______ 23.7 | 23.0} 24.0 || Plums:
Emperor, South Africa_____ 26.1 | 25.4] 26.8 || Damson, eastern grown____| 25.9
Mines $2 See | 246/246} 248 Burbank, California_______ 29.3
Mises ) Se ee | 25.2 | 24.5) 25.7 Wickson, California______-- 29.5
Olivette Blanche (Lady | | | Tragedy, California________ 27.2
[Ringe 8m ea |} 25.0} 245} 25.8 Red June, eastern-grown___| 28.1
ihe woes sae 24.8 | 23.7 | 25.7 |
Sultanina (Thompson | } 1| PAV CRAGC. 2 eo |} 28.0
Seed less pene 23.6 ° 22.95 24.7 ij ——F

Extremes

op | oF
25.9 26.5
24.2 25.8
25. 6 21-2
24.4 26.8
25.2| 25.8
24.2| 25.4
24.6| 26.7
22.4 24.4
25.1) 26.5
|

28.3} 287
26.9 | 28.4
26.9 | 27.6
27.6) 27-8
28.1 28.4
3) 238
27.9] 28.9
26. 9 28.1
27.8 28.4
26.9 | 28.2
29.5! 303
29.4 | 30.0
23.2| 289
29.3} 29.5
29.1} 30.0
28.3 29.0
29.0} 29.6
29.1 29.83
29.9} 30.2
29.3 29.9
237) 29.9
23.2} 287
29.1} 30.1
as ol

29.0| 29.7

RV RT
27.2} 28.0
26.9 | 28.7
26.4} 27.1
6.7) 27.9
WSi we
27.6} 238
27.1 | 27.5
7.1} Ri
7.2} 23.0
27.1 | 23.2
25.6} 26.3
29.0! 29.8
29.2| 29.7
26.8! 27.4
27.8 | 23.4
27.7} 23.3

1 This product is liable to be injured if stored at temperatures somewhat above its actual ee peint.

For a discussion of the proper storage temperature see the following
THE COMMERCIAL STORAGE OF FRUITS, Se AND Aue STOCKS.

R. C., and WHITEMAN, = M.

U. S. Dept. Agr. Cire. 278, 40 pp. 1933.

publications: ROsE,

H., WRIGHT,

FREEZING TEMPERATURES 5

TABLE 1.—Average and extreme freezing points of different varieties of certain
fruits—Continued

Extremes Extremes
Kind, variety, state of matu- |Aver-|-"——~———_||_ Kind, variety, state of matu- |Aver-
tity, and place where grown age’ | wrini-| Maxi- rity, and place where grown } age | jqini-| Maxi-
mum | mum mum | mum
Raspberries: SNe. a! “Caer Strawberries—Continued. ote Weedon |) ais
Ranere (St. Regis)_..--_-__ 30.4 | 30.1 | 30.5 Dorsett=. 5 eee ae 29.8 | 29.5 | 30.1
athamkaes . See se eee yess 29.8 | 29.7 | 29.8 DAN ap ee oe ee ee 29.8 | 29.2] 30.0
Cid iis ae ee 30.0 | 29.0} 30.1 AD ei Gt) de eee 29.9 | 29.3 30. 0
Potomac! a= ee 30.7 | 30.6 | 30.9 Gandy= = oes. eee 29.2 | 28.8 | 29.5
Columbians =22 28.8 | 28.2] 28.8 Glenh?Maryer. 22222 30.1 | 29.5 | 30.2
—- = Howard 17 (Premier) --___-- 30.2 | 29.6] 30.4
AV erage ue Sees she eee 29.9 | 29.5 | 30.1 Klondike s sich). seeturts | 29.6 | 29.3 | 29.9
_—S St Kellogg (Kellogg’s Pride) __| 30.1 | 29.8 | 30.5
Strawberries: upton sss aera 28.8 | 28.8 | 29.1
IBigp Wate == = ae ee = 30.0 | 29.2 | 30.0 Redheant st 2. eles 30.3 | 29.6 | 30.7
Joe: (Bigeoe) =a 30.0 | 29.8} 30.0 SPY 6) Resa a Sa eee 30.4 | 29.6 | 30.5
Blakemore=2->- 2258 29.9 | 29.7 | 30.5
Brandywine. =--2--s-)—--—= 30.0 | 29.8 30. 4 AV CT AGO Saas ok eee 29.9 | 29.5 30. 1
Chesapeake: =223. 2222-225 30.3 | 29.9 | 30.3

TABLE 2.—Summary of average and extreme freezing points of fruits

Extremes Extremes

Kind, variety, ete. A # S i Kind, variety, ete. vad 3 ;
8¢ | Mini-| Maxi- 8¢ | Mini-|Maxi-
mum} mum mum} mum
TPA TOS RCI, Oo FE | ie Eire | ce

Avocados,! Collinson___...-..- TGS OZ EW 7.4 || Citrus—Continued. :

Apples: ? Tangerine, flesh___...____-- 29.2 | 28.8 | 29.4
Summer varieties____.----- 28.4 | 28.1 | 28.6 Satsuma, Owari, flesh_____- 28.2} 27.9 | 28.7
Halland winter-=--.--=.=- = 28.5 | 28.2 | 28.8 || Coconuts: !

(Op Dae She TE pe epee ©) Oe 27.1 | 26.9 27.5 Mesh 302255 Ee ober he Ae = 25s Dy |2oro 27.0

Bananas: ! IVE soe bs ee ey eh BOR4e eee. eevee
Peel, immature__..-.------ 295.8) (2948) | 829"9)1|4Cranberries 2-2 2222 2s se PASI Pye |) PFAW
Pulp, immature 30525 230s le ee SOsOn| | Currantsess =a nose = eee 30.2 | 30.2 | 30.2
Peel, mature_____....------ 29.4 | 29.1] 29.5 || Figs, Mission, fresh, California_| 27.1 | 26.3 | 27.6
Bulpematunress=ss=— = o—- 26.0 | 25.4 | 26.5 || Gooseberries__..............._- QBAO28H7/ | 2942

Blackberries: 2 Grapes: 2
Black varieties= =. -2 52-222 28.9 | 28.6 | 29.2 American type_------------ Pa fstab Pla eH (oe
Wihitewariebye = 5-2-2222 28.4 | 28.1 | 28.6 European type__----_------ 24.9 | 24.3 | 25.5
Logan (loganberry) -------- 29.5 | 29.3 | 29.7 || Mango, Faizanson !____._..---- 29.8 | 29.7 | 30.0

Blueberry, Rubel__....-------- 27.4 | 26.9 | 27.9 || Olives, fresh,! green.....__.--__ 28.5 | 27.7} 29.4

Cherries: 2 Leth Oe hE ee eee 30.1 | 29.9 | 30.4

Sour mature, eastern-grown-_-_| 28.0 | 27.7 | 28.5 || Peaches, hard ripe__..-_._---__ 29.4 | 29.0] 29.7
Sweet mature, eastern-grown_| 24.7 | 24.2 | 25.2 || Pears,? hard ripe__-_.___-_.--_- Diels Wea) | eeonO
Sweet mature, California_.__| 24.2 | 23.5 | 24.7 || Pears,? soft ripe_______-_-----__ PAG UN PAs |W) 2233, 94
Sweet immature, California__| 25.6 | 25.0 | 26.5 || Persimmon, Tanenashi_-_-_-_---_- 28.3 | 28.1 | 28.6

Citrus: 2 Pineapples, immature__-_--_-- 29.1 | 28.7] 29.8

a Grapefruit, flesh 1_..._.___- 28.4 | 28.0 | 29.0 || Pineapples, eating ripe__.__.-_- 29.9 | 29.6} 30.2
Grapefruit, rind__.._------ PS VG FAS Dab Paya haelhboarcye Lee es ee ee 28.0 27Ee tk 23:3
WGI 61a tases oe ZBSO LE AIAOL reno MQ UINCRL as nanan ee ae ee 28.1 | 28.0; 28.4
Lemon, flesh,! California. -| 28.1 | 27.9 | 28.5 || Raspberries 2___........-_---__ 29.9 | 29.5) 30.1
Lemon, rind, California____| 28.2 | 27.9 | 28.4 || Strawberries ?._...........--__- 29.9 | 29.5 | 30.1
ime, Persian t-___....--.- 295 Se 2Osl e295) || 1 bestnuts italys22----- 2 sa2 =) 23.8 | 23.0 | 24.2
Orange, hesh ls sos ss 28.0 | 27.8 | 28.4 || Pecans, Schley_.......-_..._-_- | 19.6 | 19.2] 19.9
Orangenrind== 5525-2212. 27.4 | 26.9 | 28.2 || Walnuts, Persian ere | 20.0} 19.0} 22.1

1 See footnote 1, table 1.
2 See table 1 for freezing points of different varieties.

CHERRIES

Freezing-point determinations were made on three sour and two
sweet varieties of cherries grown on the Arlington Experiment Farm
and two varieties of sweet cherries from California. Special interest
is attached to the freezing points of the sweet varieties (table 1).
Determinations were made on both fully mature black fruit of the
two California varieties and on bright-red fruit which, although
immature, is often shipped to eastern markets. The immature bright-
red cherries were quite sour, whereas the mature dark-red to black
fruit was sweet and of good eating quality.

6 CIRCULAR 47, U. 8S. DEPARTMENT OF AGRICULTURE
GRAPES

Results were obtained from 11 varieties of American grapes, iabrusca
type, and 7 varieties of Kuropean grapes, vinifera type, all American
srown. While the average freezing point of the American grapes
crown at Arlington Farm or at the Nationai Agricultural Research
Center, Beltsville, Md., was 27.5° F., it will be noted (table 1) that
the freezing point of the Delaware ‘variety, 24.6°, is considerably
below that of the other varieties of both American and European types
due probably to the greater sugar content. In addition. there were
studied two varieties of vinifera-type grapes grown in Argentina and
South Africa to compare with the same varieties grown in California,
and also five other commercial varieties from South Africa. It will
be noted that the American and South African grown Almeria grapes
had about the same freezing point, while the same variety from Argen-
tina froze at several degrees lower. On the other hand. the Emperor
variety from South Africa froze at higher temperatures than those
from either California or Argentina. The lowest freezing point was
22.7° in the Almeria from Argentina.

All the vinifera grapes studied came from commercial shipments on
the market and were all American grown and mature except where
noted. ,

ORANGES
The average freezing points of oranges grown both in California and

Florida were determined.
PEACHES

Freezing-point determinations were made on 13 varieties of peaches
commercially grown in nearby Virginia or Maryland. Peaches in the
hard-ripe stage were utilized for these tests.

PEARS

Studies were made on five commercial varieties of pears, all Cali-
fornia grown except the Kieffer variety. They were tested both in the
hard-ripe or shipping-ripe stage of maturity and in the soft-ripe or
eating-ripe stage.

PLUMS

Freezing points were obtained for three varieties of plums grown in
California and purchased on the market and for two varieties grown
at Arlington Farm. The variety with the lowest freezing point is

Damson.
STRAWBERRIES

Freezing-point determinations were obtained for 16 varieties of
strawberries grown at the Maryland Agricultural Experiment Station
and at the National Agricultural Research Center. The greatest
difference was found between Lupton, which froze at 28.8° F., and
Redheart, which froze at 30.3°.

BLACKBERRIES, RASPBERRIES. AND CRANBERRIES

Four varieties of blackberries, one of Logan blackberries (eastern
grown), and five of raspberries were studied. Four of the varieties of
cranberries frozen were grown in Wisconsin and eight in Massachusetts.
Considerable differences were found in the freezing points of some of
these varieties. While the McFarlin variety, for instance, froze at
29°, Shaw’s Success froze at 25°.

FREEZING TEMPERATURES

MISCELLANEOUS FRUITS

|

A number of other fruits and berries were investigated, but only one
variety was available in each case. The results are included in table
2, covering the average freezing points of all the fruits studied. Three
kinds of nuts were frozen, viz, Italian chestnuts, Persian (English)

walnuts, and pecans.

FREEZING POINTS OF VEGETABLES

Although several different kinds of vegetables have been used in
the freezing-point determinations, those on which the most extensive
varietal studies have been centered are potatoes, sweetpotatoes, and

tomatoes.

These results are found in table 3.

TABLE 3.—Average and extreme freezing points of several different varieties of
potatoes, sweetpotatoes, tomatoes, and certain other vegetables

Extremes

mum; mum
oF | °F.
28.2 | 29.7
7.9 29.6
98.7 | 29.4
28.2 | 28.8
98.4| 29.5
28.0 | 29.2
99.4| 29.7
29.4 | 29.7
29.4 29.7
28.8 | 29.4
28.6 | 29.4
97.9 | 28.2
29.2} 29.8
28.6 | 29.2
30.4 | 30.6
31.2] 318
31.4] 31.8
30.8 | 31.4
31.0] 31.4
29.6 | 30.2
29.7 | 30.4
29.7 | 30.1
98.3 | 29.2
30.7 | 31.0
30.0] 30.6
29.7 | 30.2
29.0] 29.3
29.6 | 29.7
29. 2 29.3
28. 4 28.5
98. 4 |/5 98.7
98.5 | 28.7
DRS t Ish
29.1 | 29.1
28.6 28.8
29.2| 29.3
28.0] 28.3
99.5 | 29.7
29.0 | 29.6
28. 8 29.0
Deaey 28. 7
27.9 | 28.9
28. 2 28. 6

Kind, state of maturity, Aver-
and variety g
Cantaloups, eating ripe: SE:
Rocky Ford, flesh___-----_- 29. 1
Rocky, Hords rind=-=-—- == 4 28.6
ipehops flesh= at | 29.0
Lip EOD rind 0] ee 28. 3
Average, flesh___________- | 29.0
Average, rind=222-.=--2—— 28.4
Carrots:
WDANVETS! =e 2 ae ohn ee es 29.6
@hiantenayistes- as 29.5
IAVEIASE Ss sae eee 29. 6
Corn, sweet, milk stage:
Grospyze sit tee ri est | 29.1
Country Gentleman__-____- 29.1
Howhnreviobt-<2— = | 28.0
Golden Bantam _-_...------ | 29.6
PAV CRASS = ee eR 28.9
Lettuce:
May: Queen-2444 2! 2492-2 30.5
WavyepAheadre =e 31.5
Prize Hi cadse == 31.6
NV GODET nn ern eee = 31.2
IAVETAL CS Se see oe 31.2
Onions:
Mellow.banvers=_ sa 30. 1
WihitesGlope? 22213 482i 2 30. 2
‘Texas Bermuda == >= = = 30. 0
Peas:
Early Alaska_. 2 --.--.-=--- 28.9
Horsford Market Garden__} 30.9
axtonianee a2 fen ee 30. 2
PSV ORAZGs SA eae st = FS 30.0
Potatoes: ! |
IM AVOEOC) 0) 1 tay te ee ie | 29.2
irishscopbler-——— | 29.7
Spaulding No. 4__._------- 29.3
Green Mountain___.--____- 28.5
@old:@ein 22) 42-5 | 28.6
Rural New Yorker No. 2__; 28.7
RUSSOL ural 2 ee 28.3
Wp-to-Dahe see ees ae ew! | 29.1
Oregon White Rose-_-_---_- | 28.7
British Queen .-.----------} 29.3
Garnetae hii 2. ee | 28.2
American Giant_.________- | 29.6
Katahdin 239" see Sse | 29.2
VETaCe pane ee eee eb | 28.9 |
Sweetpotatoes: !
BicpieMm- A - ee | 28. 0
Wooleyets see Gol oF: | 28.5
Goldeokin—=. <5 "22k | 28.5

Kind, state of maturity,
and variety

Sweetpotatoes—Continued.
Improved Big Stem_-____-_-__|

Nancy: aliases
Mullihan--__-

SRACTSO Nene eee ee
ROLLO PICO msn aoe conse ee |

PEM Pp kite ea. 282 Ee

Red. Jersey: aes sei A
Southern Queen.-_-__------_-
Avotviriy see See ees
Yellow Belmont-_-_-_-_-------
Wellowaersey— =o
Yellow Strasburg__-.-.-___

Average = i975 Fos 2

Tomatoes, ripe: !
Bonny, Best=— =
Barlianas82- 2 342 Se

Delaware Beauty-_---------
Livingston Globe__--.-_-__-
Marcio hezsess 222 ae
Livingston Acme__-_...___-
Greenhouse varieties:
Carter Sunrise_---_-
Stirling Castle_____

Average.....-___

Tomatoes, green: !

Marslobe 24322 ss 2i0 fF
Greenhouse varieties:

Carter Sunrise_____

Stirling Castle____-

Watermelons: !
Dixie Belle, flesh___________
Dixie Belle, rind_.-_.._____
Trish Grey, flesh= = = =
~*-JrishiGrey, rind ==. =. +

Average, flesh______-__-___
Averages Ting 2 2302 ok

Aver-
age

by

STOOD EH DON BOW NID 00°"

BRBBENBE

8 §5 $0 18 $B

Hl

Ww tw Ww OD
SSossss

3
om SIND OWAWOMNOO HD OUD

Ww Oo 09 Ww OD Cw OD
SPP SEES SeSee

ww

Extremes
Mini-|Maxi-
mum |mum

Sie) sels

28.3 | 29.0

27.65 28.3

(Del) PED

28.0 | 28.7
27.9 28.7
Dee Ne B20 a:
28.3 | 28.6
28.0 | 28.6
28.3 | 23.8
28.2 | 28.8
28.3 | 28.7
28.5 | 28.8
28.3 | 29.0
28.3 29.0
2854 e285 7
SOLD OOndE
30.4 | 30.8
30.2! 30.9
30.3 | 30.7
29.9} 30.4
ZOE OF ro0s5
30.5 | 30.6
29.6 30.4
30. 1 30. 6
30.2 | 30.8
30.3 | 30.8
29.9 |} 30.3
30.3 | 30.9
30.7 | 30.8
30.4 | 30.7
30.1} 30.8
30.4 | 30.6
30.2 | 30.7
30.4] 20.8
29.8 | 30.6
30.5 | 30.6
30.3 | 30.7
30.1} 30.4
30.5 | 30.8
30.2} 30.6
29.9} 30.1
30.2 | 30.6
28.9 | 29.1
28.6 | 28.9
29.0} 29.8
28.5 | 29.1
28.9} 29.4
| 28.5 29.0

1 This product is liable to be injured if stored at temperatures somewhat above its actual freezing point.
For a discussion of the proper storage temperature see publication cited in footnote to table 1.

8 CIRCULAR 447, U. S. DEPARTMENT OF AGRICULTURE

POTATOES

Freezing-poimt determinations were made on 13 different com-—
mercial varieties of potatoes.

SWEETPOTATOES

The results of freezing 17 more or less common varieties of sweet-
potatoes are presented in table 3. The variety with the lowest
freezing point was Mullihan, one of the less known varieties, which
froze at 27.6° F. The highest freezing points were found with
Pumpkin and Yellow Jersey varieties, both of which froze at 29.0°.

TOMATOES

The freezing-point temperatures of 17 commercially grown varieties
of tomatoes are presented in table 3. These tomatoes were all
grown under the same conditions at Arlington Farm. Determina-
tions were made on both field-ripened and mature-green tomatoes
such as are usually shipped to distant markets. The lowest freezing
point (29.8° F.) of ripe tomatoes was found in the New Glory variety.
The Marglobe and Livingston Acme varieties both froze at 30.7°, the
highest freezing point in any of the varieties studied. There was no
difference in the average freezing points of ripe and mature green
tomatoes.

SWEET CORN

Four varieties of sweet corn were studied, all in the milk stage.
The freezing point varied considerably with the age of the product,
and there was also considerable variation among varieties (table 3).

MISCELLANEOUS VEGETABLES

The freezing points of three varieties of onions, four of lettuce, two
of carrots, two of cantaloups, two of watermelons, and three of peas
are also given in table 3. The freezing points of several other kinds of
vegetables where only one variety of each was studied are given in
table 4, together with the average freezing point of all of the vegetables
listed by varieties in table 3.

FREEZING POINTS OF FLORISTS’ STOCKS

The freezing points of cut flowers, plants, bulbs, corms, and tubers
that are commonly held in cold storage or shipped in quantities were
similarly determined. ‘The determinations made for 15 kinds of cut
flowers, S of bulbs, corms, and tubers, and 10 of plants are presented
in table 5. The freezing points of cut flowers were determined on
petals alone, and of plants on leaves alone. The freezing points of the
petals of cut flowers varied from 27.5° i’. in Easter lilies to 30.8° in the
orchid. The leaves of rose and peony plants froze at lower tempera-
tures than petals borne on the same stems, whereas leaves of Kaster
lilies froze at a higher temperature than the petals. The fronds of
dagger ferns, which are commonly shipped in large quantities and
stored during the winter, froze at the relatively low temperature of
23.6°. Holly leaves such as are used in large quantities in sprays or
wreaths for Christmas decoration froze at 26.3°. The foliage of
neither holly nor dagger fern was apparently injured by freezing, as is
often the case with less hardy plant material. Asparagus plumosus
foliage, which is shipped in considerable quantities, also froze at a
relatively low temperature, 24.2°. The leaves of sansevieria plants,
which are frequently shipped in large quantities for potting as orna-
mentals froze at the relatively high temperature of 31.0°. Among the

FREEZING TEMPERATURES

9

bulbs studied, tulips froze at 25.4°, and Paper White narcissus froze

at close to 29°.

TaBLe 4.—Summary of average and extreme freezing points of different vegetables

Kind and variety Aver-

age

Artichoke: oF.
Globes. 22 2a fae 29.1
JeCHUSsOM ees ees en 27.5

IA SPAR Ao Use 2 eee a ee 29.8

Beans:

Snapior ereens- 222522222 29.7
Snap: pods )a22 280 fear 30. 2
ima Dig mae teh opel pestis 30. 1
ima. POdse es ee 30. 8

1 300 ae oe eae a es 26. 9
iBrocoli, htaliant<*2. 235 2 2222 2_ 29. 2

Chicory, curled ===
Corn, sweet, milk stage________
Cucumpber3.- Se ee
Dandelion greens__________-_--
ip eoplang see See Ses 52 - ee
Indie curlede see
Endive, Belgian, imported_____
Escarole, broad-leaved endive__
Fennel, Florence__.-._______--

anoro Dw OCP PO OUI O H 00 O10 SIO SIE OD

Garlichs sae one nae ons = 25.
Horseradish 2 susees Fale a 26.
CONRAD eee ee as 30.
Oe Ses eee RE Pee EN 29.
OEE COs ses ec pe ee 31.
Muskmelons, eating ripe: ! 2
Cantaloup, flesh.________-_- 29.
Cantaloupiy rind 3322222. = 28.
Honey Dew, flesh_________ 29.
Honey Dew, rind_______-_- 28.

1 See table 3 for freezing points of different varieties.

2See footnote 1, table 1.

Extremes

| Mini-| Maxi-

mum; mum

Be) ae Send des
29.1} 29.1
PLEIAN SPL 5Y)
29.4) 30.1
29.6 | 30.1
29.9} 30.4
29.8) 30.3
30.7] 31.0
26.7 | 27.2
28.7-| 29.4
31.1] 31.3
29.4 | 29.7
29.9 | 30.1
29.7 | 30.0 |
29.7 | 30.4
30.5 | 31.0
28.6 | 29.2
30.3 | 30.6
29.5} 30.1
30.2] 30.7
30.5! 31.3
30.5; 30.9
30.0 | 30.7
28.5 | 29.7
24.6 | «35.7
25.2} 27.6
29.7} 30.2
28.5 | 29.8
31.0] 31.4
28.4 | 29.5
28.0 | 29.8
28.7 | 29.3
28.3 | 29.8

Kind and variety

oF
Mushroom, cultivated__..--_-- 30. 2 '
ORAS See S27 Bete ee eee 30. 1
Onionss nid eee ee 30. 0
Onions4strong ise 30. 1
Onion sets, Yellow Strassburg_}| 29.5
IParsnip. 2522" 2ub2en: Seas eee 29.9
iPeasereen lf eee 30. 0
Peas; podses i tac Sess eae eae 30. 0
IPEPDPeLrss green! 2s ee 30. 1
Potatoes !2_____ Sse phat tan WE, 28.9
Pumpkin, Connecticut Pie ?___} 30.1
Radish, French Breakfast___--_| 27.3
UR BDArD2 isos 2) Soe e Feee 28. 4
Romamess leet) Ate eS 30. 5
Rutabaga, American Purple
‘Roptsiae yer ers Pee 29.5

Salsifiys-2< 2 SPs sie ea 28. 4
Spinachs =. 57 Seite oe es 30. 3
Squash: ?

Summer (cymling)__-_____ 29.3

Winter; Hubbard 22224255 29.3

Italian, Cocazelle_.....-.-- 30.9
Sugar beet: 3. 335. Se 28.5
Sweetpotatoes ! ?_____.._.____-_- 28.5
Tomatoes, ripe! 2 == 30. 4
Tomatoes, mature-green !23___| 30.4
Turnips, Purple Top White

(Cio ee ee 30. 5

Watermelon, flesh___-._______- 29. 2
Watermelon, rind_..-.._-_-_-- 28.8

3 This same group of varieties when vine ripened averaged 30.5° F.

TABLE 5.—Average freezing points of certain cut flowers, bulbs, corms, tubers, and

: Aver-
Kinds age
Cut flowers (petals): C7 DE
IATIOMMON Gs sae ee 28. 1
Carnatione es 28. 4
Chrysanthemum_-_-_-_______ 28. 4
@Gardenigas ee es ee (09853
Gladiglus=s22esrs2 es 28. 7
Heath (heather) ______-____ 28. 7
Ey acinthe =e ee 28. 7
ily aWasteres— oe 2 27.5
Narcissus, Sir Watkin_-____ 30. 1
Orchid (Cattleya) _________- 30. 8
IRCOn yA tee ene ee 29.0
IROInSe Eta ee A 29. 2
VATE CUS ese 28. 6
FROSG2 sme ee ae 30. 4
surlip=eaeeee as 28. 0
Bulbs, corms, and tubers:
TT ee es a 28. 3
Giadiolus™s- see 2 SS 26. 8
(Ey ACI E he eee 28. 7

plants
Extremes
: Aver-
Kinds
Mini-| Maxi- Bee
mum] mum
She SE. Bulbs, corms, and tubers—Con.| °F.
28.0 | 28.2 Wily alla sano ae 27.5
27.9 | 28.7 Wily Recalee ae Zi
28.0 | 28.7 Narcissus, Paper White:
28.3 28. 3 | ID ORMAN tise 28.9
28.7 | 28.7 SDLOUtINg = ae ee 29. 4
28.7 | 28.7 Narcissus, Sir Watkin_____| 26.1
28.5 | 29.0 eR ipy ee See ee D4.
Be de 2iflee tle | Plants (leaves):
30.0} 30.9 || Asparagus plumosus nanus_| 24. 2
Bos |) sit @arnation sete ates ee | 27.4
a ees eee Chrysanthemum__________| 28.7
29.0} 29.5 Fern, Oregon Dagger______- 23.6
28.2! 28.9 Giadiolus= =e 26. 8
a eee Ne Holly, eastern grown__-____| 26.3
PA tt \\ Phyo Selly master see ae eee 29. 2
CODE ape ene ES es 28. 4
28.0 28. 7 TEV OS Cee eae ard AE 28. 3
2655)|) 270 Sansevieria laurentia_____-- 31.0
28.5 29. 2
]

30.1

29.

DONOR oOIwore Ne >
oy; Ont TIN wae ono COWDWOWKD WOO

SSE SSRBESS SRB S

% &
ow bo

CO bo bdo lO bo bo WwW bo
¢ SRS s SRSSSRSSSSS
Kon oomownonotIrP On-10 0°

Extreines

Mini-|Maxi-
mum | mum

CT | OF
27.5 |, 2785
27.0 | 27.8
28.2 | 29.3
29.1 | 29.9
25.8 | 26.3
24.9 | 25.4
23.5 | 24.8
DIAN NOTEA
28.7 | 28.7
23.6 | 23.6
26.8 | 26.8
23.9| 27.0

“31.0 | 31.0

10 CIRCULAR 447, U. S. DEPARTMENT OF AGRICULTURE
SUMMARY

Freezing or freezing injury does not always occur when fruit or
vegetable products are exposed to temperatures at or below their
actual freezing points. Under certain conditions many of these prod-
ucts can be undercooled; that is, cooled to a point below the true
freezing temperature of each and again warmed up without freezing
and without apparent injury. Certain products under certain condi-
tions may be actually frozen and afterwards thawed out without
apparent injury, while, on the other hand, some products are injured
by chilling if stored at temperatures well above their actual freezing
points. Evidence seems to show that different individuals of the same
‘variety and strain when grown under different conditions will have
somewhat different freezing points, and that there are also some vari-
ations in the freezing points of products of the same variety and from
the same lot. Sometimes this is due to different degrees of maturity.

In view of these facts; the freezing points given in this circular should
be considered only as danger points at or near which, either above or
below, there is a possibility of freezing injury if exposed for a sufficient
leneth of time. The temperatures given are those at which it is unsafe
to hold produce because of the danger of freezing.

The freezing points of 34 commercial kinds of fruits, 45 of vege-
tabies, 15 of cut flowers, 8 of bulbs, corms, or tubers, and 10 of plants
or florists’ greens are given. Additional data are also civen for a
number of different varieties of these kinds.

ORGANIZATION OF THE UNITED STATES DEPARTMENT OF AGRICULTURE
WHEN THIS PUBLICATION WAS LAST PRINTED

Seererary of Agricultune..- __ 5: eee Henry A. WALLACE.
WnderoSecretary= 22S. ee ee M. L. Wison.

PASSUSTAN EL SCCTELOY = 2 = ee Harry L. Brown.

Directorio; extension Works. =. 222 C. W. WARBURTON.

Directornof Fanancees. 2s Se eee ee W. A. Jump.

Director of Information. — ==. 3 ee M. S. E1sENHOWER.

Director of Personnel. __..---------------- W. W. StrocKBERGER.

Der Clr OfmeSCOnehe a ee JAMES T. JARDINE.

AAAS a NS ek ORR ne ay age a ere ea Mastin G. WHITE.

Agricultural Adjustment Administration _ = ___ H. R. Toutey, Adminisirator.
Bureau of Agricultural Economics _-_-_-_-_----- A. G. Buack, Chief.

Bureau of Agricultural Engineering___------ S. H. McCrory. Chief.
Buncawoj- Animal Industrye 2 a JoHN R. Mouter, Chief.
Bureau of Biological Survey l= === ae = Ira N. GABRIELSON. Chief.
Bureau of Chemistry and Sotls____--------- Henry G. Knieut, Chief.
Commodity Exchange Administration.s___-~-- J. W. T. Dove, Chief.

BUreduc oj Vain I naustiyne 2s ie ae O. EH. Resp, Chief.

Bureau of Entomology and Plant Quarantine__ Lez A. Strone, Chief.

Ofjiceof Papeniment, Stavions=__ = 2 = JAMES T, JARDINE. Chief.

Farm Security Administration. __...------- W. W. ALEXANDER, Administrator.
Food and Drug Administration__.---------- WALTER G. CAMPBELL. Chief.
Forest Service____----- ne eS a FERDINAND A. Sricox, Chief.
Bureainof-llome ECONOMIES 22 n= = a Lowvise STANLEY, Chief.

J GR ORS PLY 2 Se» eae a te a a ae ee eS CLARIBEL R. BARNETT, Librarian.
Bureqgucof ianteindustry 2 = 22 tS ee Fr»eperick D. Ricuny, Chief.
EULCOUAGi ee UUlee OOdS=2 2 | ee Tuomas H. MacDona.tp, Chief.
Sot) ;Consenvatvon-Seruice=— =. a H. H. Bennett, Chief.

WAC Riera Uned a ae oS Pe Wiuuis R. Greae, Chief.

This circular is a contribution from

BURCAUcOj MON TNOustry 22 3 ee FREDERICK D. Ricury, Chief.
Division of Fruit and Vegetable Crops E.C. Aucutsr, Principal Horticul-
and Diseases. turist, 7n Charge.
11

U.S. GOVERNMENT PRINTING CFFICE: 1937

¥or sale by the Superintendent of Documents. Washington,D.C. - - - - Price 5 cents