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Pumpkin and Winter Squash

Cucurbita, several species, and ornamental, wax, sponge gourd, etc.

Last revised August 6, 2004

Cucurbita Species o Seeding o Fertilizers o Harvesting, Handling, Storage o Pest Control: Cucurbit and Vine Crop Weed Control, Insects, Diseases


(See also the separate file Zucchini and Summer Squash)

Many excellent varieties exist. Only a selected few are listed below. See also the section "Harvesting, Handling, and Storage" for expected yields and size descriptions. For decorative purposes and Halloween, pumpkins from 8 to 18 lb are preferred. Larger pumpkins are valued for individual display purposes, and smaller ones are usually used in ornamental arrangements.

Production in eastern Oregon and in the Columbia Basin may be limited by curly top and other viruses. Select sites that are surrounded by crops where insects are controlled, and which are distant from open range, as this will minimize exposure to leafhopper vectors. Since vine crops are also sensitive to damage from wind, select protected sites and use windbreaks (see WINDBREAKS section below).

There is much confusion with regard to the use of the words "pumpkin" and "squash". The words have been used indiscriminately by growers, consumers and the seed industry. These words refer to culinary traits rather than taxonomic classifications.

Pumpkins are considered to be drier, coarser, and strong-flavored compared to squash and are therefore used differently in cooking. "Pumpkin" should be used to define edible fruit of any species of Cucurbita utilized when ripe in pies, and not generally served as a baked vegetable. The term "pumpkin" is also associated with the Halloween Jack-O-Lantern, and refers to fruit of any Cucurbita species (usually orange-skinned) used for that purpose.

Squash is usually divided into two categories:

"Summer squash" should be used to refer to the edible fruit of any Cucurbita species (commonly C. pepo) used when immature as a table vegetable.

"Winter squash" should refer to the edible fruit of any species of Cucurbita, utilized when ripe, as a table vegetable or in pies, the flesh of which is fine grained, mild flavored, and suitable for baking. "Winter squash" is also the term used to refer to Cucurbita fruit that is stored into the late fall or winter months. Examples would be all baking varieties of C. maxima, and the cushaw forms of C. moschata which are used when mature, and for certain varieties of C. pepo used when mature (e.g. Acorn, Table Queen) and of C. moschata (e.g. Butternut).

For other characteristics that are used to differentiate Cucurbita species, see the appropriate section below. See also Cucurbits Genetics Cooperative Home Page--a service for those interested in the genetics and breeding of cucurbits.


PUMPKIN VARIETIES

Varieties of pumpkins are listed from smallest to largest fruit. Approximate days to harvest are given for the Willamette Valley; for warmer areas, subtract 10-15 days.

Miniature, decorative pumpkins, less than 1-lb fruit, (approximately 95 days). Although used primarily for ornamental purposes, these are also suited for baking:

Sweetie Pie, and Jack Be Little 3x2 inches; also Small Sugar and Mini Jack Munchkin, 3X4 inches. White-skinned miniature: Baby Boo 3x2 inches.

Small, decorative specialty varieties (1-5 lb; approximately 105 days):

Baby Bear (6x4 in. and 1.5 to 2.5 lb), Mini-Jack (both hulless or naked-seeded); Oz, Spooktacular (both 5 inch round, uniform); Spookie, Baby Pam (both about 5X6 inches); Little Lantern (early, about 5X4 inches)

Small to medium (5-10 lb; approximately 110 days):

Triple Treat (hulless seed, fine-textured, orange-flesh, Jack O' Lantern-type fruit, concentrated maturity); Spirit (early, semi-bush hybrid, medium fruit); Jack O'Lantern (open pollinated, medium fruit); Spookie; Autumn Gold (early coloring, 7 to 10-lb, golden-yellow when immature, turning to glossy orange at maturity).

Medium to large (10-25 lb; approximately 120 days):

Howden and Kentucky Field (the classic pumpkin varieties, medium to large fruit. Howden has attractive deep orange skin and dark green stem); Jack Pot, Wizzard, and Oz (three compact-vine hybrids - medium large fruit); Connecticut Field, Happy Jack, Jumpin Jack, Pankow's Field (large stems), Big Autumn, Aspen, Buckskin (especially for processing, earlier than Kentucky Field). For trial: Bushkin (a compact bush), Howden Biggie. White pumpkin: Lumina

When pumpkins or winter squash are grown for processing for pie filling or baby food, etc., the processor specifies varieties. Proprietary varieties developed by the processor are similar to Dickenson pumpkin (C. moschata, which tends to be too late for western Oregon production), or Golden Delicious squash (C. maxima). Others may use seed blends of Golden Delicious and Boston Marrow, usually in 60:40 ratio, to plant fields for processing.

When pumpkin or squash is grown for confectionery seed, the seed processor determines the variety to be used. The most commonly used is 'Golden Delicious' squash and proprietary selections of that type. Plant spacings are reduced and plant populations are increased to produce more seed per acre. Fruit size becomes a secondary concern.

Mammoth varieties (100 + lb) "pumpkins": Big Max, Big Moon, Prizewinner Hybrid, and Atlantic Giant (patented by Howard Dill).

Note: A number of Giant Pumpkin "clubs" exist across the U.S.A. Members engage in exchange of seeds of hybrids they make. The Associations award prizes for the largest pumpkins grown regionally. For $10.00 you can join the Pacific Northwest Pumpkin Growers Assoc. Write c/o Tallina George, 15790 S.E. Hwy. 224, Clackamas, OR 97015. The 1993 Oregon record was 727 lbs. grown by Kirk Mombert of Harrisburg, OR. Also, the World Pumpkin Confederation, 14050 Gowanda Road, Collins, N.Y. 14034, holds annual weigh-off contests in the U.S. and Canada and awards cash prizes for the largest, pumpkin, watermelon and squash. For $15.00, you can join and receive their quarterly newsletter. The 1993 record was 884 lb. In 1994, a number of entries exceeded 900 lb with at least one over 990 lb. The longstanding prize of $10,000 for the person that grows the first pumpkin over 1,000 lb was officially given on October 5, 1996, for a 1061-lb pumpkin produced by Paula and Nathan Zehr of Lowville, N.Y. A pumpkin grown in Canada also broke the 1,000 mark at 1,006 lb. Both were of the Atlantic Giant variety. See also the World Class Giant Pumpkins and Giant Gourd Growing Contest.

Naked-seeded or hulless varieties (approximately 110 days). Seed is used for roasting:

Trick or Treat; Triple Treat (round, 10-inch diam., may be used for Halloween pumpkin, seed roasting, and pumpkin pie); Lady Godiva (grown only for its seed), both compact and indeterminate vine types are available.

WINTER SQUASH VARIETIES:

Among winter squash varieties, only Butternut and Golden Delicious are used for processing. Fruit quality is related to increased days to harvest provided vines are healthy and fruit is not subjected to extended cold or freezing temperatures.

Varieties are listed by type. Approximate days to harvest, for good quality, are given for the Willamette Valley; for warmer areas, subtract 10-15 days. Fruit quality is related with increased days to harvest provided vines are healthy and fruit is not subjected to extended cold or freezing temperatures.

Acorn (approximately 110 days): Green: Table Ace, Table Queen. For trial: Tay Belle, Royal Acorn, Unicorn.
Yellow: Table Gold.

Banana (approximately 120 days): Pink Banana, Pink Banana Jumbo. For trial: Blue Banana.

Butternut (approximately 120 days): Butternut Supreme, Early Butternut, Waltham Butternut. For trial: Butter Bush, Hercules, Ultra Butternut (a very large butternut suitable for processing), Nicklow's Delight ZYMV (ZYMV and CMV resistant, semi-bush hybrid), Ponka, Neck Pumpkin (long neck).

Buttercup (approximately 115 days): Sweet Mama, Buttercup Burgess Strain.
Orange-skinned buttercup type: Gold Nuggett. For trial: All Seasons F1(orange); Butter Boy (red-orange);

Kabocha: Kabocha is the generic Japanese word for squash, but refers most commonly to a squash of the buttercup type: Delica (also known as Ebisu in Japan, is one of the most common varieties), Kurinishiki F1, Honey Delight, Sweet Mama. For trial: First Taste, Home Delite, Imperial Delite, Supreme Delite, Sweet Meat.

Delicata (or sweet potato squash; approximately 110 days): Sugar Loaf, Honey Boat, Delicata.

Delicious (approximately 115 days): Golden Delicious, N.K. 530, N.K. 580 (all having the red-orange, tender, rind required in processing squash and thick orange-yellow flesh; N.K. 580 is the largest). Green Delicious (green rind).

Hubbard (approximately 120 days): True Hubbard, Blue Hubbard, Golden Hubbard, Baby Hubbard, Warted Hubbard, Red Kuri (also called Baby Red Hubbard or Orange Hokkaido), Uchiki Kuri (orange-red).

Spaghetti (C. pepo; approximately 100 days): Vegetable Spaghetti, Pasta F1, Tivoli F1 (bush spaghetti), Orangetti (orange rind and flesh, higher in vitamin A than Vegetable Spaghetti). These are used as spaghetti substitute. These have become popular and much more common in the marketplace recently.


ORIENTAL VINE CROPS:

Vegetable Sponge, Dish-cloth gourd, Sponge gourd (Luffa sp.; approximately 120 days). These may be used for cooking when immature, or allowed to mature for the fibrous spongy tissue: Angular types (Luffa acutangula): San-C, Ping-Ann. Cylindrical types (Luffa aegyptica): Cylinder, Seven Star, Seven Beauty. These produce higher quality sponge fiber.

For more information on Luffa, see the North Carolina State University file Commercial Luffa Sponge Gourd Production.

Wax gourd (Benincasa hispida; approximately 125 days): Green Tiger, Cheerer. Both are late, needing a long season and hot temperatures.

Bitter melon or Balsam Pear, Bitter cucumber, Bitter gourd (Momordica charantia) see Oriental seed catalogs for variety availability under one or more of the above names.

American Indian pumpkins and squash:

An unusual collection of varieties of C. maxima, C. mixta, C. moschata and C. pepo is offered by Gleckler's Seedmen, a company that deals with unusual seed specialties (see address below). Seeds of Hopi, Shawnee, Omaha, Pueblo, Cochiti and other American Indian as well as Mexican Zapotec and Calabaza varieties are listed. These would be best suited in the warmer, longer season areas of the Snake and Columbia River valleys.

Calabaza (Cuban pumpkin C. moschata; approximately 130 days): A subtropical (but may mature in the warmer areas of Oregon). Fruit is of high quality, 5-7 pounds, slightly flattened at top and bottom, mottled green or yellow and tan. Flesh light yellow. Long vining plant. Leaves are mottled, gray-green. Used primarily by Hispanics: La Primera, Marian Van Atta's.


ORNAMENTAL SQUASH AND GOURDS:

Turban C. maxima (approximately 115 days): Turk's Turban, Tiny Turk.

Gourds (ornamental, yellow-flowered C. pepo; approximately 100 days): Bi-Colored Pear, Apple, Nest Egg, Crown of Thorns, Yellow Warted, Small Orange, Flat Striped, Miniature Stripe, Pear Stripe.

Bottle, Dipper etc., Lagenaria species (approximately 125 days), white-flowered: Bird House, Bottle, Calabash, Cave Man's Club, Dipper; Italian Edible (also called Cucuzzi, may be eaten when immature, makes a nice rattle when mature and dried, resembles a bowling pin but rounded at the bottom). Trichosanthes anguina Snake gourd. These are all quite late. Note: Some varieties of "gourds" are not palatable when mature.

Note: For more information on gourds, contact the American Gourd Society, POB 274, Mt. Gilead OH 43338


CHARACTERISTICS DIFFERENTIATING SOME COMMON CULTIVATED CUCURBITA SPECIES

Species               Foliage     Stems         Fruit stalk   Seed margin

C. pepo             Spiculate   Hard angular   Hard, angular  Smooth
(zucchini and all    (spiney)                    ridged
summer squash; acorn;
small,colored gourds;
spaghetti squash;
Connecticut Field;
Jackolantern; ridged
orange skin).

C. maxima           Moderately   Soft, round    Soft, round,  Smooth
(Hubbard, Banana,     spiculate                 enlarged by
Delicious                                       cork tissue

C. moschata         Non -       Moderately    Hard, smoothly  Scalloped
(butternut, Ken-    spiculate      hard,          angular,
tucky Field, Dic-                 smoothly        flared
kenson; smooth orange-            angled
brown skin), Calabaza
Note: Vine crops of many other genera and species of the family Cucurbitaceae exist and are grown commercially, but to a lesser extent than those described above.


SEED AND SEED TREATMENT

In western Oregon, pumpkins and winter squash are planted from early to mid May. Some early varieties and acorn squash may be planted to mid June.

Pumpkins and squash in the species C. pepo have seed numbering approximately 100-300 per ounce. Those in C. moschata and C. maxima have seeds numbering approximately 200-400 per ounce. Use fungicide-treated seed. Pumpkin and Squash seedlings are susceptible to damping-off and decay when soils are cool and wet.


SOILS AND SITE SELECTION

Choose light, well-drained soils for earliest crops and reduced risk of stand establishment problems. Avoid using fields in your rotation in which muskmelons, watermelons, pumpkins, squash, cucumbers or other cucurbits have been planted.

Squash and pumpkins grow best on fertile, well-drained soil supplied with organic matter. The ideal pH for pumpkin and squash growth is between 6.0 to 7.5, but they will grow on soils with a pH of up to 8.0. Consult a soil test for fertilizer and liming recommendations.

Winter squash and pumpkin root to a depth of 48 inches or more. Maintain soil moisture above 60% of the soil water holding capacity. It is important to regulate irrigations properly to avoid excessive moisture or water stress.

For Kabocha squash, use well drained soils to minimize occurrence of ground spot (light green or yellow spot). Clay soils should be avoided as should any locations that may increase the probability of fruit surface scarring.

The minimum soil temperature required for germination of these crops is 60 F, with the optimum range between 70 and 95 F.


WINDBREAKS

Use windbreaks as necessary especially in eastern Oregon. Grain windbreaks have been found effective when grain rows are used for each crop row. Winter wheat varieties, rye, or oats can be used. Spring barley may be used for February plantings. Seed grain thickly, 2-3 seeds per inch. This requires about 10 lb of barley, 9 lb of wheat, or 8 lb of rye to seed grain rows 12 feet apart.

Crop rows and windbreaks should be cultivated after they are well established. Windbreaks may be cut off or rotary tilled around June 25 before vines develop long runners that may be damaged by tractor tires.


SEEDING

Pumpkins and squash are usually direct-seeded when all danger of frost has passed. Transplants may also be used.

Final spacings depend on vine size and intended use. When growing pumpkins or winter squash for processing, narrow spacings are used. Use spacings of 3 to 4 feet between rows and 1.5 to 2.5 feet between plants within the row.

Plantings intended for fresh market are usually planted at wider spacings:

 Vine Type                    Between Rows     Within Rows
Bush or short vine varieties:    3 to 5'         2 to 3'
Small-fruited large vines:       6 to 8          3 to 4
Large-fruited large vines:       6 to 8          4 to 5
A common spacing of 3' x 5' would produce 2,900 plants/acre and up to 4,000 10 to 15-lb pumpkins, for a yield of about 20-30 tons/acre.

While wide spacings (8 x 3 feet) are generally recommended for Kabocha types for optimum skin color and reduced disease incidence, yield at this wide spacing would be low (about 5-6 tons per acre). A spacing of 6 feet between rows and 1 to 1 1/2 feet between plants in the row has been used successfully in New Zealand, and to a limited extent in Oregon, and should be tried. This should result in yields of approximately 8-10 tons per acre.

For confectionery seed production, spacings of 3 feet by 3 feet are commonly used. At these populations ground cover is dense and flowers are quickly hidden under the canopy. For good set, high bee populations (2-3 hives/acre) and prompt hive placement (soon after the first female flowers open) are important for good pollination and seed set.


FERTILIZER

Good management practices are essential if optimum fertilizer responses are to be realized. These practices include use of recommended varieties, selection of adapted soils, weed control, disease and insect control, good seed bed preparation, proper seeding methods, and timely harvest.

Because of the influence of soil type, climatic conditions, and other cultural practices, crop response from fertilizer may not always be accurately predicted. Soil test results, field experience, and knowledge of specific crop requirements help determine the nutrients needed and the rate of application.

The fertilizer program should insure adequate levels of all nutrients. Optimum fertilization is essential for top quality, yields, and returns.

Recommended soil sampling procedures should be followed in order to estimate fertilizer needs. The OSU Extension Service agent in your county can provide you with soil sampling instructions and soil sample bags and information sheets.

Recommendations are based on a row spacing of 60 inches. With decreased row spacings fertilizer rates should be increased.

Western Oregon soils:

Adjust pH to 6.0 or above.

Nitrogen (N)

Rates of 80 to 150 lb N/A are suggested with the lower rates of N being applied when legumes were grown the preceding year or a green manure crop is incorporated into the soil prior to planting. Apply one-half the nitrogen at or just prior to planting and the rest when vines begin to "run".

If the application of N plus potash (K2O) exceeds 50 lb/A, there is danger of seedling injury from the concentration of salt when fertilizer is banded at planting time.

There is less danger if the band application is split into two bands. The danger is aggravated as the band comes closer to the seed. The danger is greater with sandy than with finer textured soil. Immediate irrigation at the first sign of burn should reduce further injury. There is more possibility of damage to seedlings on acid soils where the pH is below 5.5.

Phosphorus (P)

Phosphorus fertilizer should be banded at planting for vigorous early seedling growth. Bands should be located 2" to the side and 2" below the seed.

         If the soil test*     Apply this amount of
        for P reads (ppm):    phosphate (P2O5) (lb/A):
              0 to 15                 120-150
             l5 to 60                  90-120
              over 60                  60- 90
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.

Potassium (K)

Potassium should be applied before planting or banded at planting time. Amounts above 40 lb K2O/A should be broadcast and worked into the seedbed. See statements on fertilizer banding under "Nitrogen".

          If the soil test*      Apply this amount of
         for K reads (ppm):       potash K2O (lb/A):
              0 to  75                100-150
             75 to 150                 60-100
            150 to 200                 40- 60
              over 200                  None
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.

Sulfur (S)

Include 20-30 lb S/A in the annual fertilizer program for vine crops. Use the higher rate on sandy soils. S is sometimes contained in fertilizers used to supply other nutrients such as N, P, and K but may not be present in sufficient quantity.

Plants absorb S in the form of sulfate. Fertilizer materials supply sulfur in the form of sulfate and elemental S. Elemental S must convert to sulfate in the soil before the S becomes avail able to plants. The conversion of elemental S to sulfate is usually rapid for fine ground (less than 40 mesh) material in warm moist soil.

Sulfur in the sulfate form can be applied at planting time. Some S fertilizer materials such as elemental S and ammonium sulfate have an acidifying effect on soil.

Magnesium (Mg)

When the soil test value is below 1.5 meq Mg/100g of soil or when calcium (Ca) is ten times more than the Mg, apply 10-15 lb Mg/A banded at planting. If Mg deficiency symptoms appear, spray with 10 lb Epsom salts in 100 gal water/A.

Magnesium can also be supplied in dolomite, which is a liming material and will reduce soil acidity. Dolomite should be incorporated into the seedbed at the rate of 1-1 T/A.

Boron (B)

In general, boron deficiencies are uncommon. If the soil test value for B is less than 1 ppm, an application of 3 lb B/A is suggested. Boron should be applied uniformly to the field as a spray or broadcast. Never band B fertilizer.

Zinc (Zn)

Zinc deficiencies are uncommon in Willamette Valley soils. When the soil test is below 1 ppm Zn, a response to Zn is expected and 4 lb Zn/A should be included in the fertilizer band.

Lime

Experimental work has shown that vine crops will produce good yields over a fairly wide range of soil acidity. Lime applications are suggested when the soil pH is 5.6 or below, or when calcium (Ca) levels are below 5 meq Ca/100g of soil.

The rate of lime application can be estimated from the following SMP buffer table:

              If the SMP buffer*     Apply this amount of
             test for lime reads:         lime (T/A):
                  Below 5.2                   4-5
                  5.2 - 5.6                   3-4
                  5.6 - 5.9                   2-3
                  5.9 - 6.2                   1-2
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science. The liming rate is based on 100-score lime.

Lime should be mixed into the soil at least several weeks before planting. A lime application is effective over several years.

Some soils may have a fairly high SMP buffer value (over 6.5) and a low pH (below 5.5). This condition can be caused by the application of acidifying fertilizer. In this case the low pH value is temporary and the pH of the soil will increase as the fertilizer completes its reaction with the soil. This temporary "active" acidity from fertilizer is encountered following recent applications of most N fertilizer materials. Acidifying fertilizers also have a "long term" acidifying effect on soil that is cumulative and leads to lower SMP buffer readings.

Sandy soils to which fertilizers have not been recently applied sometimes record low pH and high SMP buffer values. In such cases, a light application of 1-2 T/A of lime should suffice to neutralize soil acidity.

For acid soils low in Mg (less than 0.8 meq Mg/100g of soil), 1 T/A of dolomite lime can be used as a Mg source. Dolomite and ground lime stone have about the same ability to neutralize soil acidity.

The possibility of seedling injury from the band application of fertilizer is less when the soil pH is 5.6 or above. Some Willamette Valley experiments have shown decreased uptake of phosphorus from band applications of P when the pH approaches 5.5.

Lime applications should be broadcast, preferably in the fall, and incorporated into the seedbed. Do not plow lime down leaving the surface soil unlimed.

Fertilizer Guide #3, "Liming Materials for Oregon", which is available from your local OSU Extension Office, provides additional information on lime.

These fertilizer recommendations are based on research conducted by OSU Horticulture and Crop and Soil Science faculty, and are quoted from OSU Fertilizer Guide FG 68.

Eastern Oregon soils:

Nitrogen: 40-60 (N) lb/acre (banded at time of planting).

Just before the vines begin to spread, side-dress with another 25-50 lb N/acre. Where mulching and trickle irrigation is used, nitrogen can be fed through the trickle irrigation at 15-25 lb/acre when the vines begin to spread. To prevent clogging or plugging from occurring use soluble forms of nitrogen (Urea or Ammonium nitrate) and chlorinate the system once a month with a l0-50 ppm chlorine solution. Chlorinate more frequently if the flow rate decreases.

Phosphate: 115-125 (P2O5) lb/acre (banded at time of planting).

Potassium: 50-100 lb/acre as indicated by soil test. If any K is needed, broadcast and disk-in prior to planting.


POLLINATION

It is recommended that one honey bee hive should be introduced for every 1 to 2 acres during the blooming period since naturally occurring bee populations may not be adequate, or their activity may not coincide properly with the bloom period.

Pumpkins and winter squash bear separate male and female flowers on the same plant (monoecious). Bees transfer pollen from male to female flowers making fruit set possible. Information from Michigan and New York indicates that pumpkin flowers need 8-10 visits per female flower for adequate pollination and that each female flower is only receptive for about 24 hours. Research at OSU supports this finding. Multiple pollinator visits are needed, with the number dependent on crop, bee species, time of day, temperature, and other factors.

Although a pumpkin plant will continue to form female flowers over a period of several weeks, delayed pollination may also results in an undesired delayed maturity. Pumpkins produce from 25-35 female flowers per plant and many male flowers. In large-fruited pumpkins about 5% of the flowers need to be set to produce an economical yield. In small-fruited varieties, as many as 40% of the female flowers may need to be set for an economical yield. For more information on beehive quality and pollination, see the OSU Publication PNW-245 Evaluating Honey Bee Colonies for Pollination, A Guide for Growers and Beekeepers.


STIGMA DEATH

In addition to pollination, development of female flowers may be affected by temperature. Recent experience in the Middle Atlantic states and in New England indicates that high night temperatures (above 65 F) are associated with failure of female flowers to open and develop properly. The ovaries turn yellow and then shrivel and the stigma of the unopened flower exhibits black streaks into the ovary. 'Howden' is particularly susceptible.


IRRIGATION

Pumpkins and winter squash require uniform irrigation for optimum growth and yield. Reduce irrigations as fruit reach harvest stage. A total of 12-15 inches of water may be needed in western Oregon and 20-25 inches in eastern Oregon, depending on seasonal variation, area and variety. Approximate summer irrigation needs for the Hermiston area have been found to be: 3.5 inches in May, 5.0 in June, 7.5 in July, and 7.0 in August.

See also the OSU Irrigation Guide for this crop.


HARVESTING, HANDLING, AND STORAGE

In the Willamette Valley, Golden Delicious squash are harvested for processing from September 15 to October 31 from mid-May plantings. The prime harvest period is from September 15 to October 15.

Processing squash: Mechanical aids (tractor mounted V-shaped sweeps) are used to windrow Golden Delicious squash for mechanized pick up and loading into trucks for fruit intended for processing. A mechanical butternut squash harvester was developed by Gerald Malburg, a Michigan grower, in 1993. It is reported capable of harvesting 20-25 tons per hour.

Fresh market squash: All fresh market pumpkin and squash is harvested by hand. Pumpkins can be harvested anytime after their rinds are hard and their skins have turned orange, and the ground side has developed a yellow color. Harvest before they are injured by freezing or too much rain. Extended exposure (1-2 weeks) of pumpkins and winter squash to temperatures below 50 F. can result in chilling injury, and excessive decay in storage. Cut pumpkins from the vines, leave 3-4 inches of stem attached to the fruit since pumpkins without stems do not store well. Do not handle pumpkins by their stem since they may easily break off.

Good yields of small varieties range from 5 to 7 tons or 2000 to 4000 fruit per acre. Large pumpkins may yield 10 to 20 tons or 1,000 to 2,000 fruit per acre.

Yields of specific varieties of pumpkins and winter squash obtained from multiple year data from the Dixon Springs Agricultural Research Center in Illinois:

                                         Average yield   Fruit Size
      Variety           Number/acre          tons/A         (lb)   
      Howden Field        2,400               22.9           19
      Connecticut Field   1,300               11.7           18
      Thomas Halloween    1,250                8.8           14
      Jackpot             2,250               14.6           13
      Trick or Treat      2,300               13.6           12
      Spirit              3,600               19.8           11
      Pankow's Field      2,200               12.1           11
      Autumn Gold         5,150               23.2            9
      Little Boo (white)  1,600                3.2            4
      Spookie             5,800               10.2            4
      Baby Pam            2,550                2.6            2
      Mini Jack           5,200                3.9            1

Information from Michigan indicates that in general, good to excellent yields of Halloween pumpkins are generally 15 to 20 tons per acre.

Yield of seed from hulless or naked-seeded pumpkins should range from 800 to 1500 pounds per acre.

Winter squash should be harvested only when fully mature. Indications of maturity are a hard rind and a solid exterior color. The acorn types are harvested when a yellow-orange color has developed on the fruit where it is in contact with the soil. To harvest, remove the stem completely from the fruit, and allow the stem scar to dry before storing.

Yields of Hubbard, Marrow and other large squash, pie pumpkins, acorn, butternut and summer squashes would be 15-20 tons/A; gourds 4-5 tons/A; and buttercup squash are 10-15 tons/A.

Due to the wider spacings needed for Kabocha squash, gross yields of this type of buttercup squash would more likely be 5 to 10 tons/A of well colored fruit (see other comments about yield in the section on SEEDING above). Data from the OSU experiment station in Medford in 1988 obtained the following marketable yields of three types of "Kabocha":

      Variety         tons/acre   lb per fruit   Culls tons/acre
      Sweet Mama        16.0          4.42            9.1
      Honey Delight     19.3          4.36            3.6
      Kuryjiman         15.3          3.27            3.8

Kabocha squash is harvested by cutting the stem and leaving 1 to 2 inches. Ideal fruit size is 3 to 6 lb.

Research (with muskmelons) suggests that pumpkins and winter squash may benefit from being dipped in 135-140 F water for 3 minutes, and dried quickly before storage. Warm, wet fruit are subject to invasion by micro-organisms, therefore drying and cooling to the storage temperature should be done immediately following this treatment. This hot water treatment surface sterilizes the fruit. No benefit has been found from chlorination of the hot water, but gently wiping the surface clean with 1 part household bleach in 10 parts of water may be helpful.

STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)

Store at 50 to 55 F and 50 to 70 % relative humidity. Pumpkins and winter squashes are placed on racks, in bulk bins, or baskets and are held in ventilated or common storage in production areas. Most cultivars of pumpkins do not keep as well as hard-shelled winter squashes; both types of vegetables are subject to chilling injury at low temperatures. Such cultivars of pumpkins as Connecticut Field and Cushaw cannot be expected to hold in good condition more than 2 to 3 months at 50 to 55 F.

All winter squashes should be well matured, carefully handled, and free from injury or decay when stored. They should be kept dry, and storage rooms should have good air circulation. Relative humidities of 50 to 70 % (60 % may be optimum) are recommended for pumpkins and winter squashes, which are lower than those recommended for most vegetables. Higher humidities promote decay and lower humidities cause excess weight loss and texture deterioration.

Acorn-type squashes, such as Table Queen, should keep 5 to 8 weeks at 50 F. At higher temperatures 60 to 70 F, Table Queen will lose greenness, become undesirably yellow, and acquire a stringiness of the flesh in 5 weeks. At 32 to 40 F yellowing does not occur but chilling does. Alternaria rot develops on chilled squashes after their removal from storage.

The popular Butternut squash should keep at least 2 to 3 months at 50 F. Often it is stored for longer periods, but spoilage and shrinkage increase. Weight loss should be kept below 15% to minimize development of hollow neck, and a relative humidity of 50% is recommended.

Kabocha, Turban and Buttercup squashes should keep at least 3 months under good conditions. Since kabocha squash intended for export must meet stringent skin color and other quality standards, kabocha intended for export should be handled as per the export company specifications.

Hubbard squash, if in good condition initially, can be successfully stored 6 months at 50 to 55 F with 70% relative humidity. A 15% loss in weight from shrinkage for 6 months storage would be average.

A 10 to 20 day curing period at 75 to 80 F before storage is sometimes recommended for pumpkins and winter squashes. However, experiments in New York showed that a preliminary curing for 3 weeks at 80 F before storage to heal mechanical injuries and to ripen immature specimens was unnecessary. Curing Butternut, Hubbard, and Quality squashes was of no value but not harmful, whereas curing Table Queen was detrimental to skin color, texture, and taste. Cured Table Queen also decayed more rapidly than uncured fruit.

Less rot will develop in the Hubbard squash if stems are completely removed before storage. Hubbard squash and other dark-green-skinned squashes should not be stored near apples, as the ethylene from apples may cause the skin to turn orange-yellow. Black rot, dry rot, and bacterial soft rot are the principal causes of spoilage of winter squashes in storage.


PACKAGING

Winter Squash - hard types: 42-lb (l-l/9 bushel) crates; 800 to 900-lb bulk bin cartons, collapsible and reusable; 900 to 2000-lb various bulk bins.

Pumpkins: commonly packaged in various size crates and weights or shipped in bulk truck loads.


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