Pumpkins (or winter squashes) are members of the Cucurbita genus. Popular species of the Cucurbita genus include: C. Pepo, C. Maxima and the C. Moschata species. To determine proper times for harvesting pumpkins and winter squashes one must consider the species and variety.
Members of the C. Pepo species include miniature sized orange pumpkin varieties, such as the Jack Be Little that can be less than a pound or larger varieties like large field pumpkins such as the Connecticut Field or Gold Rush variety pumpkins. Suprisingly some large field pumpkin varieties can be grown to as much as 100 lbs or more. On the lower end, smaller members of the C. Pepo species can harvest from seed to maturity in as little as 75 days. On the upper range, larger varieties will harvest in as much as 115 days or more. For the orange, field pumpkins of the C. Pepo species, try to obtain as much of the deep orange color as possible on the vine (the fruit when immature will be green and transition to orange as it becomes mature) prior to cutting. If for whatever reason you must harvest when the pumpkin is green (yet matured) you can let it sit in sunlight for a few days and it will develop its nature orange color, you should however monitor it during this time as critters or insect pest may find it if it is still close enough to the garden.
C. Maxima species members include smaller pumpkin varieties such as the Lumina which is white in color and might average around 8 to 10 lbs in weight while harvesting in about 105 days. The largest C. Maxima variety is the Atlantic Giant of which the current world record and is over 2,000 lbs. For these large Atlantic Giants you can expect the fruit to mature for harvest in 150 or more days. For C. Maxima species members, just like for C. Pepo’s look for a full development of color in the fruit and for very large fruits netting of fruit surface such as with a cantaloupe can occur.
Pumpkin varieties belonging to the C. Moschata species include the Fairytale and Long Island Cheese varieties. While these varieties have a sweet flesh great for baking, they do harvest in a longer period of time. In general, these varieties will harvest in no less than 120 days for smaller fruits and as much as 140 days for larger varieties. These fruits will range in weight from 6 to 30+ lbs and at maturity should have a deep tan color, sometimes spotted with green or can have a very light purple color. At fruit maturity, the plant vines and stems will dry out and become wood like in color and texture.
These time frames for harvest dates should be considered as approximate and as a minimum for when fruits will become mature and be ready for picking. For this reason be sure to record and take note of when pumpkin seeds or transplants are planted in the ground. You will expect in general that upon maturity the fruitskin will become very hard such that it could not be easily punctured. Also as fruit matures, vines and leaves will begin to become dry and begin to die off as the plant is nearing the end of its life cycle. As the time frame for harvesting approaches, watch the fruits periodically so that when ready, pumpkins are removed from the vines and not left in the field or garden longer than is necessary. In late summer and early autumn, there are many harmful insect pests and diseases present in your garden usually in great numbers that will target the pumpkins and could potentially ruin them before you can harvest them.
When cutting pumpkins from the vine, try to leave as much stem on the pumpkin as possible as this will help the pumpkin to last longer and provide a physcial barrier to prevent disease from getting to the pumpkin at the stem location. C. Maxima varieties are sometimes referred to as soft stem varieties and sometimes (especially if the plant was less healthy and/or diseased) the pumpkin stems will begin to prematurely decay starting at the stem tip working its way to the pumpkin. Once the stem has rotted away all the way to the pumpkin surface, fruit rot at that location in the pumpkin will soon follow. Sometimes cutting a long stem will buy you more time in a manner of speaking.
Plan on harvesting pumpkins before the first frost of the season. Not only will pumpkin plants not last a frost but neither will pumpkins. Pumpkins exposed to below freezing conditions will begin to decay quickly.
RESOURCES / REFERENCES:
Ron Wolford, Unit Educator, Urban Horticulture and Environment; Drusilla Banks
Extension Specialist, Food Science and Nutrition Programming
Watch Your Garden Grow, Pumpkin; University of Illinois Extension
Retrieved from: http://urbanext.illinois.edu/veggies/pumpkin.cfm
B. Rosie Lerner and Michael N. Dana, Originally authored by Juliann Chamberlain
Growing Cucumbers, Melons, Squash, Pumpkins and Gourds; Department of Horticulture, Purdue University Cooperative Extension Service
Retrieved from: http://www.hort.purdue.edu/ext/HO-8.pdf
Ontario Ministry of Agriculture, Food and Rural Affairs, Pumpkin and Squash Production Fact sheet (March 2000); ISSN 1198-712X; Agdex #: 256; Prepared by OMAFRA staff
Retrieved from: http://www.omafra.gov.on.ca/english/crops/facts/00-031.htm