If you are planning on growing pumpkins in your garden this year, you might be wondering how big the plants and fruit will get. That way, you can plan the number of plants and the amount of space you will need for your crop of pumpkins.
So, how big do pumpkins grow? Pumpkins grow 10 to 30 inches (25 to 76 centimeters) tall, 4 to 16 feet (1.2 to 4.9 meters) wide, and produce fruit that weighs between 4 ounces and 200 pounds!
Of course, the quality of your fruit (if you get any at all!) depends on the care that you give your pumpkin plants. Let’s take a closer look at pumpkins, including size, growing conditions, and time to maturity.
How Big Do Pumpkins Grow?
Pumpkin plants generally grow to a height of 10 to 30 inches (25 to 76 meters), with a width (spread) of 4 to 16 feet (1.2 to 4.9 meters). This means that pumpkins will take up a lot of ground space in your garden.
Miniature pumpkin varieties, such as the Mini Harvest Hybrid Pumpkin Blend from Burpee, can produce fruit as small as 4 ounces.
On the other hand, some larger pumpkin varieties, such as the Atlantic Giant Pumpkin from Burpee, can produce fruit that weighs 200 pounds or more.
How Long Does It Take Pumpkins to Grow and Ripen?
Pumpkins can take between 70 and 120 to days to mature, depending on the variety. According to the University of Maryland, most pumpkins take 100 days or more to ripen.
Pumpkin seeds usually germinate in 7 to 10 days. It is preferable to sow your pumpkin seeds directly into the soil where the plants will grow. However, you can start seeds indoors 3 weeks before transplant to avoid late spring frosts.
What Do Pumpkins Look Like?
Pumpkins are oval or round, and they start off with a green color. Most pumpkins become orange when they are ripe, although some can be white, yellow, red, or other colors.
Are Pumpkins Hard to Grow?
Pumpkin plants like full sun and warmer temperatures, so they can be difficult to grow in colder, northern regions with short growing seasons.
One way to offset this problem is to start seeds indoors and then transplant the established pumpkin plants outdoors in the spring, after the last danger of frost has passed and soil temperatures are a bit warmer.
Temperature for Pumpkins
The minimum temperature for pumpkin seed germination is 60 degrees Fahrenheit (15.6 degrees Celsius). If the soil is any colder than this, you will see low germination rates – that is, if you can get any seeds at all to germinate!
This is nature’s way of protecting pumpkin seeds from sprouting at a time when they will be unable to survive. This is why it is suggested that you start pumpkin seeds indoors to avoid cold soil temperatures in early spring.
The maximum temperature for pumpkin seed germination is 105 degrees Fahrenheit (40.6 degrees Celsius). If the soil is any warmer than this, germination rates will decrease.
Combined with high humidity, high temperatures can encourage the growth of mold, which is another threat to your plants. So, don’t wait too long to plant your pumpkin seeds and transplant your established plants outside!
The Old Farmer’s Almanac suggests starting pumpkin seeds indoors 2 to 4 weeks before the last spring frost date, and waiting until the soil temperature is at least 70 degrees Fahrenheit (21.1 degrees Celsius) before transplanting outdoors.
The ideal (optimal) temperature for pumpkin seed germination is between 85 degrees Fahrenheit (29.4 degrees Celsius) and 95 degrees Fahrenheit (35 degrees Celsius).
Keep in mind that these temperatures refer to soil temperature, not air temperature. If you want to find out the soil temperature, use a probe-type thermometer to check.
If the thermometer reads a temperature that is too low, then you have some options. One option is to wait until the sun warms up the soil.
To speed up this process, clear away any debris, such as leaves or grass clippings, from the soil surface. Also make sure to choose a location for planting that gets plenty of sun, so that it can warm up the soil faster.
If you are worried about a short growing season, you can also use a cloche (a plastic or glass cover) to trap some heat and warm up the air and soil near your pumpkin seeds.
A cloche can be made from a plastic water bottle to retain warmth and humidity in the soil for seeds or seedlings as they grow.
For more information, check out the table below, and check out this article from the University of California on ideal seed germination temperatures.
|Ideal||85 to 95||29.4 to 35|
Watering for Pumpkins
Pumpkins need lots of water, so water deeply at the base of the vine (try to keep the leaves and the fruit itself from getting wet, especially on the bottom). If you find that you have a problem with dry soil, check out my article on how to treat dry soil.
On the other hand, over watering your pumpkin plants (or any plants for that matter) can lead to root rot and eventual death. The best way to decide when to water is to feel the soil with your fingers.
If the soil feels dry 2 or 3 inches below the surface, then go ahead and water. For more information, check out my article on over watering your plants.
Try to water early in the morning, rather than at night, to allow water to soak into the soil. Avoid getting the leaves wet to prevent rot, mold, and diseases.
Also, avoid getting the pumpkin fruit itself wet, especially on the bottom. In damp weather, it may help to put a thin piece of wood underneath the pumpkin fruit so that it is not in contact with the soil.
Fertilizing for Pumpkins
Use a balanced fertilizer (such as 10-10-10) early in the pumpkin plant’s growth, to encourage vine and leaf growth. Avoid excessive nitrogen, since this can burn plants or encourage too much green growth at the expense of flowers and fruit.
For more information, check out my article on over fertilizing your plants.
Switch to a high-phosphorus fertilizer just before the flowers bloom. For more information, check out my article on high-phosphorus fertilizers.
For more information on fertilizing, check out this article on pumpkins from the Old Farmer’s Almanac.
Spacing for Pumpkins
Pumpkins extend their vines in all directions, and take up lots of ground space in your garden. You might need 50 to 100 square feet per hill (pumpkins are normally grown in small mounds of soil called hills).
Sow your pumpkin seeds 1 inch deep in the soil, planting 5 seeds per hill. Leave 5 feet between hills, and leave 10 feet between rows if you have multiple rows.
After the pumpkin seeds germinate and begin to grow, thin the seedlings to leave the best 2 plants per hill.
For more information, check out my article on thinning seedlings.
Spacing requirements may vary depending on the pumpkin variety: there are vining, semi-bush, miniature, and bush varieties to consider. For more information, check out this article on pumpkins from the University of Illinois Extension.
How to Grow Big Pumpkins
If you want to grow really big pumpkins, there are a few extra steps to take.
First, wait until your pumpkins reach the size of a softball (a diameter of 3.5 to 4 inches or 8.9 to 10.2 centimeters).
Then, remove all but the best pumpkin fruit on each plant. That way, each plant will concentrate all of its energy on this one fruit, leading to a bigger pumpkin.
Also, be sure to keep the area around the pumpkin and its vines free from all weeds and other plants. This prevents competition with other plants for sunlight or for water and nutrients in the soil.
Finally, water your plants from below, and avoid getting the vines and leaves wet to avoid rot. Each leaf will absorb more sunlight, create more energy, and add to the size of the pumpkin!
By now, you have a much better idea of how big pumpkins grow, in terms of both the fruit on the vine and the plant itself. You also know a bit more about the care that is necessary to ensure a healthy crop of pumpkins in this year’s garden.
I hope you found this article helpful – if so, please share it with someone else who can use the information. If you have any questions or advice about pumpkins, please leave a comment below.