How Much Sun Do Pumpkins Need [The Answer May Surprise You]
Do Pumpkins Need Full Sun
While pumpkins will grow without full sun, it is not ideal. Full sun is required for the pumpkin plants to thrive. Pumpkins grown in full sun will live longer, produce more pumpkins, and grow bigger, better pumpkins.
What Is Full Sun
The definition of full sun is 6 or more hours of direct, unfiltered sunlight each day. This is the minimum amount of sunlight your pumpkin plants should receive each day.
Why Sunlight is Important for Pumpkins
Sunlight is important for several reasons.
First, your pumpkin leaves, stems, and vines all contain chlorophyll. This is what absorbs energy from the sun and creates sugars that feed the plant during photosynthesis. This plant food is then moved through the vines to the pumpkin fruits. This is why more sun yields bigger and more pumpkins because there is more food for the pumpkins to feed on.
Second, sunlight keeps the leaves dry which prevents mosaic viruses and fungal diseases from spreading as rapidly.
Sunlight also helps keep soil temperatures warm. Pumpkins thrive in soil temperatures between 65 and 95 degrees Fahrenheit. Warm days and cool nights are perfect growing conditions and the soil will not stay warm without direct sunlight to heat it up.
How Much Sun Do Pumpkin Plants Need
I always say that pumpkins are like Superman. They are charged by the sun. Without it they grow weak.
At a minimum, pumpkins should have 6 hours of direct sunlight. Eight to ten hours is better though. This is why planning where to plant your pumpkins is so important.
For a complete guide on planning and planting pumpkins, read the article Planting Pumpkins: The Definitive Guide.
Which Direction Should Pumpkin Vines Grow for Most Sun
It doesn’t matter which direction your vines run as long as they have full sun. For most of us in the northern hemisphere, it’s best to plant your pumpkins on the south side of any structure. This will ensure those leaves get morning and afternoon sun and maximize your sunlight exposure.
Will Pumpkins Grow in the Shade
Yes, pumpkins will and can grow in the shade but your plants will most likely stop producing early. If you grow pumpkins in the shade, plan to harvest them early. Pumpkins also grow much more slowly in the shade.
One year I experimented with this and grew some pumpkins under a shade net. I had way fewer pumpkins and my plants started to die off after about 2 months. I did have some pumpkins grow, but most of them were much smaller in size.
Image: Experiment growing pumpkins in shade.
Furthermore, shade makes your pumpkins more susceptible to pests and diseases. You may have to deal with more aphids and mosaic viruses when you grow in the shade (University of Illinois).
It’s best to expose your pumpkin leaves and vines to as much sunlight as possible.
Can Pumpkins Grow Without Direct Sunlight
Pumpkins will grow in indirect sunlight and tolerate some shade, but it is not ideal. Shaded vines grow more slowly and produce fewer flowers if there is not enough direct sunlight.
Plants also may be weaker and have a higher risk of insect damage because of it.
How to Know if Pumpkins Are Not Getting Enough Sun
If you’ve already planted your pumpkins and you’re not sure if they’re getting enough sun, here are a few indicators (besides watching the sun and timing it on your stopwatch all day).
If your vines look long, tall and thin with very few leaves and flowers, you most likely have a sun deficiency.
You may be able to correct it by (very carefully) moving the vines in a different direction so they are not under whatever is shading them. This may not be possible if shade is coming from a large structure such as your house. But if a tree or a small fence is shading them, you may be able to gently turn the vines in a different direction.
Other than that, you could always knock down whatever is shading them, but that’s probably not practical.
You can also check your soil temperature. Sunlight not only is required for the plant to feed itself but it also is required to warm the soil. If you don’t have a soil thermometer, you can buy one cheap from Botanical Interests. That’s where I got mine and it works great.
If you already have a thermometer, put it in the ground near your plant and check the temperature. If it’s below 65 degrees Fahrenheit, you may have a sunlight issue.
You can always check your soil by hand, although it’s much less accurate. Simply stick your hand in the ground (not too close to the pumpkin roots so you don’t damage them) and if the earth feels warm after a few minutes, your temperature is probably fine - no issues.
Can Pumpkins Get Too Much Sun
Not really. Pumpkins love warmth and sunlight. When people talk about pumpkins getting too much sun, what they really mean is that the plant is experiencing too much heat. That can be a problem because it will dry out your soil rapidly and if your pumpkin plant doesn’t stay hydrated, it will become stressed.
Too much sunlight could also mean the soil has heated up too much which will also stress your plants. If the soil temperature exceeds 100 degrees Fahrenheit for too long your pumpkin plants will stop growing.
So again, the issue isn’t too much sunlight, but rather water deficiency and hot soil temperatures.
How to Prevent Heat and Dehydration in Pumpkins
If you experience a heat wave there are a couple of things you can do.
First, if the temperature exceeds 85 degrees, increase your watering. I use ollas in my garden, but on heat waves, I will give my pumpkins an extra drink from the hose. They need to stay hydrated or the leaves will start to droop and turn yellow.
Second, I have utilized shade tents over my pumpkins when concerned about the soil temperature heating up. I don’t like to use them for extended times because the pumpkins also don’t like shade. But when deciding between the lesser of two evils, I’ll choose the shade for a few days vs. my pumpkins not growing.
You can get quality 40% and 50% shade nets at Gardener’s Supply Company at an affordable price below. I always keep several of these on hand for my entire garden because I live in Southern California and heat waves are all too common. And lately, they’ve seemed to last longer and longer during the summer months.
Lastly, stop fertilizing during heat waves. Fertilizers including blood meal and bone meal (commonly used with pumpkins) contain salts which can dry out your soil more.
For more information on pumpkin fertilizers and when to use them, read the guide on Pumpkin Fertilizers.
How Much Sun Do Pumpkins Need Conclusion
Pumpkins need a minimum of 6 hours of direct, unfiltered sunlight. They will perform better with 8 to 10 hours, however.
Pumpkins will grow in the shade, but their growth will be stunted and their growing season will be shortened.
If your pumpkin vines are long, tall, and thin you may have a sunlight deficiency. Try and gently relocate your vines in a direction with less shade.
It is rare for pumpkins to get too much sun, but they can suffer from dehydration and hot soil temperatures.