When do pumpkins bloom?

From Seed to Harvest: The Growth Stages of a Pumpkin

It Starts With a Seed

Like most plants, pumpkins start out as nothing more than a seed. Roughly triangular, the pale yellow seed contains everything needed to grow a mature plant.

Once you plant the seeds in warm, moist soil, you only have to wait approximately a week for the first two leaves to appear.

From Seed to Sprout

Once germination has occurred, two small green leaves will break through the earth. These two leaves are not actually “true” leaves, but are instead known as the sprout.

Many people actually grow these pumpkin sprouts to eat, especially during the winter months when fresh greens are not readily available. These small plants will eventually turn into pumpkin plants.

True Pumpkin Leaves

About a week after the sprout has emerged from the ground, you will see the first leaves appear. You can differentiate between true leaves and sprouts by paying attention to the following:

  • Sprout leaves are small and round.
  • True leaves grow from the center of the plant between the sprout leaves.
  • The leaves are dark green.
  • The leaves have jagged edges.

Within a few more weeks, the leaves will continue to develop. Once these three leaves form, the rest of the plant begins to proliferate.

Formation and Growth of Pumpkin Vines

Once the leaves are established, you can almost see the pumpkin plant begin to grow. Almost daily, you can see the vines grow longer and spread out away from the base of the plant. Under the right weather and water conditions, pumpkin vines can increase by as much as six inches (15 centimeters) each day!

Midway through the growing season, the pumpkin vines will suddenly be covered with bright yellow flowers. The first flowers to bloom are the male flowers. They stand erect and have a stamen in the center that is covered with pollen.

The female pumpkin flowers appear about ten days after the male blossoms.

Tip: Be sure to leave male flowers on the vines until after the females have closed up. Pollination cannot occur without both male and female flowers.

Fruits Begin to Form

Once the female blossoms have closed, you will see small green fruits appear at the base of the flower. These little orbs are infant pumpkins, so when you see them, you can be sure pollination was successful.

Over the next weeks, the baby pumpkins increase in size. Within a few weeks, you can definitely tell it is a pumpkin, albeit a green one!

The Last Few Weeks of the Growing Season

The last few weeks of the pumpkin growth stage, the green fruits reach their final size and begin to turn their trademark orange color. Be sure to turn the pumpkins occasionally so the sun can reach all sides; otherwise, you will end up with green streaks on the pumpkin!

Tip: Keep in mind that not all pumpkins types are orange. The color depends on the variety you planted.

The Final Harvest

At the end of the pumpkin growing seasons, the pumpkin vines will begin to turn brown and wither. At this time, you can harvest the pumpkins and enjoy the final stage of their growth-eating them!

The pumpkin that grew itself

(Editor’s Note: This article was originally published on November 23, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)

Weeds are volunteers. So are the flowers that so delightfully self-seed in the garden and do not have to be replanted year after year. There are always tomato plants popping up around the area where I had my tomato containers the year before. They come from whatever tomatoes fell and did not get cleaned up. Every so often, there is something unaccounted for, a plant with totally unknown origins. Maybe the wind brought the seed or it was delivered by a bird (a nice way of saying it was in bird droppings). Perhaps it was even planted by one of the fairies that dwell in our Fairy Garden. Do not confuse these plants with the different type of volunteer you see in the photo at left. That is one of our granddaughters, a volunteer; i.e. a young person who works in our garden in exchange for hugs and kisses.

My husband and I had one such plant in our rose garden this year. Never was a seed planted so out-of-place. Or with such serendipity. I first noticed it growing in a spot near the edge of the garden where a rose had died the previous year and had not been replaced. Not sure exactly what it was, but fairly certain it was not just a weed, I let it grow. And grow it did! It took off like a shot.

When we had narrowed the identification down to some kind of squash, we decided it could stay. After all, the missing rose had left a kind of forlorn empty space. My husband was rooting for pumpkin. We had never grown any. Not that we didn’t want to, but space is limited and pumpkins need room to roam. I thought zucchini would be nice. It has been a while since I made Double Chocolate Zucchini Cake. Our son has even offered to buy zucchini if I would make the cake. Any winter squash would have been welcome as they generally store well.

There was room for the main vine along the slate path. All I had to do was train it around the outer stone wall for a bit and then turn it down the pathway. It was just a matter of placing stones at strategic spots. My garden cart would no longer fit along that section, but that was not a big inconvenience. When a secondary vine started, I let it run straight through that section of the garden, right between the rose bushes.

As our volunteer plant began to flower, it gave me a chance to give a little lesson in Plant Biology 101. Husband expected every flower to become a fruit. I explained that the ones with the long stems were male flowers and are usually the first to bloom. Then come the female blossoms, identified by a swelling at their base which will develop into a fruit if the flower is pollinated.

Finally, in the middle of August, a female flower was pollinated and began to grow. It was the sole fruit on that vine. There was one on the secondary vine that started to develop but dried up and dropped off. Within a week, the little fruit started to look like a pumpkin, although it was somewhat long and skinny. So there it was, our first and only pumpkin. I did spray it once with some VeggiePharm® when I was spraying our patio vegetables . That was the total extent of my involvement in the small miracle of this pumpkin. You would think that a seasoned gardener might take this happening with a grain of salt, but I was fascinated. I guess you can tell by the number of photographs that were available when I decided to write this article.

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It was easy to check on our pumpkin’s progress, because I rarely miss a daily walk through my rose garden. Would it make a full foot tall? It topped out at 11¼ inches, but with the stem it is 13½. The day it started to color up, I had to stop what I was doing to go back to the house and make a report. That is, after I took a picture. Our family thinks we’re nuts, but they chalk it up to old age and medication. Looking back, I guess we were behaving like we had a world record cucurbit (the latin name for a member of the gourd family). In our defense, it is a record for our garden.

We began to agonize over when to harvest our precious pumpkin. Since Dave’s Garden is built on top of a mountain of gardening information, I went to a DG friend in Maine for advice. Photos of her beautiful squash harvest (at right) are credentials enough for me. ‘I don’t pick my pumpkins until the vine looks dead,’ she said. ‘I try not to pick them until Oct. 1, in hope they will last until Halloween. Doesn’t always work.’ So that is exactly what I did. After the vines died, on October 5, I cut it off and brought it in to grace our dining room table. You can see the result in the opening thumbnail.

Dear pumpkin had a hole in its backside (now, now, people, I just mean the side that faced the ground) that made us speculate about its keeping power. However, Halloween approached and it showed no signs of softening. It was so pretty on the table, we considered trying to keep it for Thanksgiving. The threat of rot and the urge to carve overcame that pretty quickly. There are so many more creative things to do with a Halloween pumpkin than the traditional Jack-o’-lantern. I knew I had seen some great ideas in a magazine but, of course, could not locate it in the organized clutter I call my home. It was October 30th, so I turned to the web and went to Better Homes & Gardens and found just what I looking for. Something tall and narrow to fit the shape…a haunted house painted black with cutouts for the windows and a large moon. When it was cut open, the walls proved to be very thick and the hole-in-the-bottom didn’t even go all the way though to the inside. The carving was easy…windows are mostly straight lines. It’s a good thing, too, because I never got to the carving until October 31. There were a lot of compliments from trick-or-treaters, mostly moms or older kids. The little ones just want their candy.

This pumpkin really was a gift, one of the surprises that truly makes gardening a joy. We hope fun and interesting volunteer plants will continue to bless our garden in the future. If it was a fairy pumpkin and we treat our fairies right, maybe they will plant something new for us… next year.

Please take a look at Sally Miller’s wonderful article tomorrow, Beginner Pumpkins. It will be a great help to you in case you are not blessed with a volunteer.

In case you missed the other great Pumpkin Week articles that ran earlier here are links:

What looks like a Shmoo and is edible? A Cushaw! by Darius Van d’Rhys (Tuesday, 11/18/08)

Miniature Pumpkins: Big Reasons to Grow This Tiny Beauty by Jeannette Adams (Wednesday, 11/19/08)

Fresh Pumpkin, Perfect for Pie! by Diana Wind (Thursday, 11/20/08)

Pumpkin for Pets by Geoff Stein (Friday, 11/21/08)

Many thanks to pixie62560 for the use of her terrific squash harvest photograph. All other photographs are ©grampapa and may not be reproduced without the express permission of the author.

Please see my previous article, I Never Promised You a Rose Garden, for more about my Rose Garden.

I prefer organic solutions when possible. VeggiePharm® is an organic fungicide/pesticide. I have no other interest in Pharm Solutions, Inc., the manufacturer of this product.

Please see my previous article, My patio farm diary, the back forty square feet, for more about my patio vegetables.

Pumpkin Plant Not Producing: Why A Pumpkin Plant Flowers But No Fruit

A common problem when growing pumpkins is…no pumpkins. It’s not all that unusual and there are several reasons for a pumpkin plant that is not producing. The primary reason for healthy, glorious pumpkin vines but no pumpkins is lack of pollination. So how can you tell if your pumpkin got pollinated?

How Can You Tell if Your Pumpkin Got Pollinated?

Chances are good that if the vines have been completely devoid of fruit, the culprit is likely pollination or rather lack of it. If you did see some small fruit, they may have aborted due to a stressor such as hot, humid weather, lack of water, or some critter decided to munch on them.

Pumpkins are members of the Cucurbit family, which includes squash, cantaloupe, watermelon and cucumbers. All of these members rely on bees for pollination. They produce both male and female flowers. Male flowers appear first, so if you see the pumpkin vine flowering but no fruit and it’s early in the season, don’t panic. It just may be a matter of waiting for the female flowers. Female flowers appear further down the vine and may not show for up to two weeks after the appearance of the males.

It’s easy to tell the difference between the male and female blossoms. Male flowers are borne straight off the vine while females have a small fruit swelling at the base near the stem. Males are produced first to entice bees into programming them into their pollen route.

If the weather is overly hot and humid early in the season, some plants delay the production of female flowers. If the pumpkin delays female blossoming, late sets often do not have time to develop before the days shorten and colder weather sets in. Also, too much nitrogen in the soil can result in the production of primarily male pumpkin vine flowering or even lush, healthy pumpkin vines but no flowers or pumpkins.

If, however, you’ve checked and have both male and female flowers and it’s late in the season, there was probably an issue with pollination.

Additional Reasons Why a Pumpkin Plant Flowers but Sets No Fruit

As mentioned, weather may be why a pumpkin plant flowers but sets no fruit. Not only heat, but drought stress often causes the pumpkin to develop more male flowers and delay females. Flooded soil will also damage root systems, causing wilting and flower or fruit abortion.

Planting too close together increases shade, which will affect how and when the pumpkin flowers. Close competition also makes it difficult for bees to get to the blossoms. The shaded areas may also be under pollinated because it is cooler. Bees get lazy when it’s below 60 degrees F. (15 C.) and temps in shaded areas may be too cool to entice them.

Pumpkin flowers are only open for about 6 hours beginning at sun up. Bees only have this window of time to move the pollen from male to female blossoms and several visits to the female need to occur for successful pollination (one visit every 15 minutes!). Windy, stormy weather also keeps the bees in bed, so reduced fruit sets occur.

To increase the likelihood of successful pollination, you can try your hand at it, literally. Hand pollination may be the way to go. Hand pollinate before 10 a.m. on a day when a female flower is about to open. You may need to keep an eye on them for a few days. Select a male flower and touch the stamen with your finger to see if the pollen comes off. If it does, the pollen is ready. You can use a soft brush or cotton swab or remove the entire male flower to transfer the pollen from the stamen of the male to the stigma of the female.

If all goes well, meaning the weather cooperates, the plant gets 6-8 hours of sun and consistent water, hand pollination is a fairly sure way to correct a pumpkin plant that is not producing.

How to Grow Huge Pumpkins

Most champion pumpkin growers have their own methods and secrets for producing the gigantic pumpkins that win pumpkin contests every year. Of course, it is necessary to start with the right kind of pumpkin seed, one that is selectively bred to produce the really big pumpkins such as “Prizewinner Hybrid” which, with the proper growing methods, can produce pumpkins in the 300-pound range.

Pumpkin Culture

Pumpkin plants need a lot of sun. Choose the sunniest place you have; remember that pumpkins are sensitive and will need shelter from wind and frost. Try to protect pumpkins from the worst of the elements by covering them during heavy rains, or putting up some kind of barrier to protect the vines from high winds or using shade tents during summer’s hottest days.

Pumpkins like and need a lot of water, but don’t plant pumpkins in wet or dense soil. They need good, well-drained soil. You can dig it up by hand. Don’t use a tractor, pumpkin roots don’t go down very far. Prepare the soil in early spring, as soon as the ground is warm. Fertilize the patch with a good four inches of rotting cow manure. Pumpkins do best in soil that is slightly acid or nearly neutral.

If you live in a part of the country where there is still danger of frost in late April or early May, start pumpkin seeds indoors about two weeks before planting. Sow one seed for every four-inch peat pot filled with grow mix. Keep the pots watered, never let them dry out.

How to Plant Pumpkins

When seedlings have the fourth or fifth leaf, set them outdoors in hills about the size of a pitcher s mound, one plant to a hill. Protect pumpkin seedlings the first few weeks with plastic-covered frames. Space each hill at least 20 feet apart.

Growing Fall Pumpkins and Gourds

How to Fertilize Pumpkin Plants

Pumpkin plants have two kinds of flowers, male and female, which appear in early July. The male flowers show up first, followed by the females. Look out for the first female flowers. Look for vines to be strong and well-established before letting a female flower set fruit. It might help to break off the first female on each vine and wait for the second or third, when the vines are at least ten feet long. A female is easy to recognize: she has a baby pumpkin at the base of each flower.

You need a big vine to produce a big pumpkin, so in a sense you’re choosing the vine before the pumpkin. When you find a vine that’s strong enough and a female flower on the verge of opening, put a bag of cheesecloth over it for the night to keep the insects out. The next morning pick a fresh male bloom, trim off the corolla or outer petals, and rub the pollen-laden stamen in around the center of the newly opened female bloom.

How to Grow Pumpkins

This is just the beginning of a summer of long but rewarding work. What you have started is actually a pumpkin-producing factory. Remember that there are 100 or more leaves to each vine and if you are trying to grow a 300-pound pumpkin, each leaf is responsible for up to four pounds of weight in your pumpkin. Every leaf, every stem, every hair roots is now receiving sunlight, absorbing water, and blending nutrients. All are traveling down the all-important stem to your prize pumpkin.

Giant pumpkins balloon out from the vine and if precautions are not taken, they will tear away and lose touch with their all-important stem. Since vines put out roots at every leaf, tear out the roots of the vine where it is close to the pumpkin. This will give it free room to grow without damage to the vine. Gently train vines away from the pumpkin to prevent it from crushing them, try giving them a nudge in the right direction every day.

When two or three fruits on each plant reach the size of softballs, remove all but the most promising one and start to prune the pumpkin plants. After the primary vine has reached 20 feet, pinch off the tips and the side shoots so the vines won’t divert resource from the fruit. Break off all the other female flowers A potential prizewinner is forming. The work of the plant now must go entirely toward nurturing this fruit alone.

It is important to remember that the only thing that will increase the size of the fruit comes out of the vines and the vines must get support from the natural root. For growing really big pumpkins, the most important things to remember are seeds, soil, sunshine, and water.

By mid-August the plants are pulling in water and nutrients at a great rate. Nighttime is when pumpkins do their growing, most expand two inches in circumference every night.

If it’s a dry season, give each plant 15 to 20 gallons of water twice a week. Water in the evening, and water only the base of the plant to keep the leaves dry, which reduces the risk of disease.

Female pumpkin flowers dying before opening

Someone else had the same problem… Here’s what the North Dakota Agricultural Extension had to say about it:

“The female flowers were tightly closed up with no access to the lobes that I’m supposed to transfer the pollen to. Any ideas? (E-mail reference, San Jose, N.M.)

A: I don’t know why the female flowers are not opening. Where did you get the seed? It could be a variety (cultivar) problem where your day-length, temperature extremes, or sunlight intensity is not conducive for reproductive activity. It may also be a fertility problem: pumpkins are greedy feeders of nutrients, but an imbalance of too much nitrogen could cause problems as well. Or, since reproduction requires an outlay of energy, perhaps the female flowers are not opening or aborting because they are grown in partial shade and simply have not accumulated enough carbohydrate reserves to develop pumpkin fruit. I would suggest getting the soil tested for nitrogen, phosphorus, potassium, soluble salt levels, pH, and organic matter content. Also, check to see what the amount of direct sunlight contact with the vines are. They need full sunlight to be productive.”

Forum on female flowers drying up before getting a chance to pollinate:

The female flowers open early in the morning, & you can check the night before to detect which ones should be opening the next morning:

“The female flowers open very early in the morning, perhaps about sunrise. If you look closely, you can tell when a female flower will be opening the next morning because the normally green petals will develop a yellowish tinge in the evening, around supper time. The yellowish ones will open tomorrow morning, the green petaled ones will open some other, later day. Same thing with the males- when the petals get yellowish in the evening, you know they will open the next morning….”

When you do find an open female flower to pollinate it should be pollinated before 10 a.m. …because pollination carried out at the end of the morning during warm weather has very little chance of success because the pollen will have heated up and fermented and will no longer be viable. Also, it will be more successful if several male flowers are used to pollinate one female flower. Pollination needs to be made to all segments of the female flower. Here’s a picture & more instructions:

Good luck!!! Hope this is helpful.

What to do when flowering squash fails to produce

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Q: My squash plants flower, but the flowers are not opening fully and fall off without developing squash. Can you tell me what is happening to my plants?

A: There could be a couple of reasons why you are not getting fruit. And they are both related to the pollination process that allows squash to produce. A single squash plant has both male and female flowers blossoms. The male blossoms are small and on a slender stalk. The female blossoms are generally larger and have visible fruit below the blossom.

A common problem in squash and pumpkins is that flowers appear early in the season but fruits fail to set, but that’s because usually the early flowers are males. Until the female flowers develop, somewhat later, pollination can’t occur, and the small fruit will abort. However In hybrid varieties of summer squash, the first flowers are usually females; but they too will fail to develop if male squash flowers aren’t present.

Squash flower pollen is heavy and sticky, so it requires bees or other insects to transfer it from male to female flowers. Wind won’t suffice. Lacking insect pollinators, you can become the pollinator for squashes and pumpkins. Using a soft brush, Q-tip or a feather, gently brush the yellow pollen from freshly opened male flowers (the ones with the long stem) on to the female flowers (with a short stem and miniature fruit at the base of flower). Do this early in morning while the blossoms are open. Blossoms are only viable for one day. The trick is to be able to differentiate between male and female flowers.

But given that it is later in the season and we have had a very hot summer, the most likely reason is that with our prolonged hot weather the pollen may not be viable, this would also explain the flower not opening fully. Under very warm or damp conditions, the entire set up for squash pollination can fail because of the premature death of pollen grains or slow growth of pollen tubes.

The situation can be further aggravated if you are watering overhead because moisture-loving bacteria and fungi like to grow on the failing flower and shriveling fruit.

To confirm this diagnosis, look your plants over carefully. Make sure there are some male flowers among the females, because some hybrid varieties produce almost all female flowers. Also check that you have buzzing bees early in the day when temperatures are cooler. If both types of flowers are present and you have pollinators buzzing around, then as temperatures dip down into the 90s you should start to see baby squash forming.

Also, it is important to pick the shriveled flowers off the plants and compost as they can cause fungi or bacteria to grow that may further hinder squash production.

The Shasta Master Gardeners Program can be reached by phone at 530-242-2219 or email [email protected] The gardener office is staffed by volunteers trained by the University of California to answer gardeners’ questions using information based on scientific research.

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