When you look around and see those hefty, festive pumpkins all over in autumn, it’s almost hard to believe that they all started with just a small seed. But it’s true!
Pumpkin growing stages happen over 3 to 4 months in 8 distinct steps:
- Planting the seed
- Germination occurs
- True leaves appear
- Vines start to grow
- Flowers develop
- Pollination occurs
- Fruits form
- Ready for harvest
In this article, you’ll learn the details of each stage in the growth of a pumpkin and why it’s critical for pumpkin production. We’ll also look at how to harvest your pumpkins correctly and how to preserve them for long-term use.
Let’s get started!
Pumpkin Growing Stages: Overview
Note about pumpkin fertilizing: Pumpkins are heavy feeders, meaning that they need lots of nutrients from the soil to produce healthy fruits. And which fertilizer is best depends on the growing stage:
- Nitrogen for early plant growth, or germination to just before flowering. This corresponds to stages 1-4 on our list. Blood meal, like this organic formula from Burpee, is a great option during this time.
- Phosphorus supports abundant pumpkin blossoms, and therefore the chances for more fruit. Give your pumpkins extra phosphorous during stages 5 and 6 from this list. Bone meal, also available as an organic formula from Burpee, is a fantastic source of phosphorus.
- For maximum fruit production, which occurs during stages 7 and 8, your pumpkins need both phosphorous and potassium. Vegetable Food fertilizer from Master Nursery has a good balance of the major nutrients.
Stage 1: Plant the Seed
The best start for pumpkin plants is healthy seeds. They’re shaped a little like a triangle and pale yellow when you get them out of another pumpkin or a seed packet.
These are average days to maturity for some favorite pumpkin varieties:
- Mini pumpkins like Munchkin and Baby Boo average 90-100 days and are good for decorating.
- Small pumpkins like Baby Bear and Cinderella average 100-115 days and are perfect for pies.
- Medium pumpkins like Magician and Magic Lantern average 98-100 days and are good for jack-o-lanterns.
- Large pumpkins like Gladiator and Kratos take up to 120 days to ripen.
- Giant pumpkins like Atlantic Giant can take up to 160 days to reach full maturity.
The best time to plant pumpkin seeds is once all frost danger has passed and the soil is consistently 65 degrees Fahrenheit. If soil temperatures are below 60 degrees F, start your pumpkin seeds indoors about 2-3 weeks before your last expected regional frost date.
Place 3-4 seeds pointy end down under 1 inch of soil. Give water often enough to keep the soil moist but not wet. After that, it’s time to wait just a bit for the next stage to appear.
Stage 2: Germination Occurs
Germination refers to the new plant breaking through the soil surface. In general, germination for pumpkin seeds takes about a week up to 10 days, though that depends on the specific variety and environmental conditions.
Once your pumpkin germinates, you’ll see the first two leaves, which are small and green. These are referred to as the cotyledons, or embryonic leaves, and are actually not true pumpkin plant leaves. Cotyledons contain nutrients and can perform limited photosynthesis to support and nourish the young plant.
These seedlings will continue to need moist, well-draining soil and bright light for 6 hours or more each day.
Stage 3: True Leaves Appear
After germination and the first leaves appear, the next phase in the growth stages of a pumpkin is when the true leaves start to appear.
These leaves are a darker green with jagged edges, and they grow out of the center of the pumpkin plant and between the cotyledons. And this is just the beginning of what a pumpkin plant looks like. True pumpkin leaves indicate a healthy seedling and potential for awesome pumpkins!
If you started your pumpkins seedlings indoors, they’re ready to transplant outside once they have at least one full set of true leaves and the outdoor soil temperatures are consistently 60 degrees F or higher.
Stage 4: Vines Start to Grow
Once the first true leaves have grown and developed, the pumpkin vines will start growing rather rapidly under the right conditions. According to Penn State Extension, pumpkin vines need the following for optimal growth:
- Six or more hours of direct sunlight daily. Pumpkins are sun-lovers, and they’ll happily take all the hours of sunlight they can get!
- A spot in the garden with well-draining soil
- Plenty of water on the roots, but not the foliage (a soaker hose is ideal here!)
- A thick layer of mulch helps keep the soil comfortably moist
- Temperatures between 65 and 95 degrees F
If you can maintain these conditions for your pumpkin vines, you can expect to see them grow up to 6 inches per day! For miniature or small pumpkins, training the vines to grow on trellises helps support the vines and saves you some garden space.
Stage 5: Flowers Develop
After about a month of growing, it’ll seem like the vines are just covered with yellow flowers. The first flowers to develop are the male flowers (they’ve got a central stamen covered in pollen).
About 7-10 days after the male flowers bloom, the female flowers (which look like they have a tiny pumpkin at the bottom of the blossom) will open up.
Healthy flowers are critical to pumpkin production- it’s time for pollination!!
Stage 6: Pollination Occurs
Pollination is where pollen from the male flowers gets transferred into the female flowers, allowing them to develop their immature fruits into full-grown pumpkins. Pumpkin plants only produce flowers for a short window of time, and if those flowers don’t get pollinated, there will be no pumpkins.
Penn State Extension tells us pollination by the intensive activity of insects (like bees, butterflies, etc) is essential for the production of pumpkins. So one of the best ways to get lots of pumpkins is to encourage healthy bee activity. Companion planting native blooming plant species near your pumpkins is a great way to provide a consistent food source all season long, drawing those busy bees in.
You can also hand-pollinate your pumpkin flowers with a finger, a cotton swab or a small paintbrush. Collect pollen from the center anther in the male flower (it will look fuzzy due to the pollen). Then touch the female pistil located in the center of the female flower to distribute the pollen.
Stage 7: Fruits Form
At this stage, you’re literally seeing the fruits of your labors.
When there’s successful pollination, you’ll see the blooms shrivel up, die and fall off. What’s left behind from the female flowers are tiny green pumpkins that begin growing. Once you’ve hit this stage, your pumpkins should be ready for harvesting in about 5 to 8 weeks. Smaller varieties usually reach maturity faster, and the larger ones take more time.
Especially with the mid to large-sized varieties, turn the pumpkin every few days to help the fruit develop a nice rounded shape. Some growers also find that placing a piece of cardboard or wood underneath the pumpkin helps prevent rot by keeping it away from direct contact with the soil.
You can also trim vines that don’t have any pumpkin growing on them. This helps you save garden space and encourages your pumpkin plant to channel all its energy into the growing fruits.
Stage 8: Ready for Harvesting
It’s almost fall, your pumpkin vines are starting to die away and your pumpkin fruits are a lovely orange, white or any other color their variety is supposed to be. Is it time to harvest? Here are some signs your pumpkin is ripe:
- It’s covered in waxy, dull skin that can’t be punctured with a fingernail.
- The pumpkin sounds hollow when you thump it with your hand.
- The appropriate color for the variety you planted is fully developed on the entire fruit.
- The stem feels dry and similar to a cork.
But don’t try to harvest all of your pumpkins at once- individual fruits can ripen at a different pace, so check each one before you harvest it.
Use a sharp knife or pruning scissors to cut the pumpkin off the vine, leaving 3-4 inches of stem to protect the fruit from rot and also to look decorative. Be sure your pumpkins are dry when you harvest them to help them store longer.
Preserving Pumpkins After Harvest
To help your pumpkins last longer in storage, set them out in a dry and sunny spot for 2 weeks or more. This is called curing, and it allows your pumpkins to develop a hardened rind that slows down the decaying process. Curing enables your pumpkins to last for several months, which means you can make pumpkin pie for Christmas too!
After curing, pumpkins should be stored in a cool, dry place. A root cellar is ideal, but a basement shelf or cardboard box in the garage should suffice as well.
Frequently Asked Questions about Pumpkin Growing Stages
Pumpkins come in so many delightful and colorful varieties! It’s so fun to watch them grow and develop on the vine, and with distinct growing stages, it’s pretty easy to see where your plants are in the life cycle.
So keep an eye on what your plants are up to currently, and you’ll have a pretty good idea of when you can expect to harvest those fall pumpkins!
Do you have any other questions about the growth of a pumpkin? Or maybe you’ve successfully grown pumpkins before and have some tips to share. Either way, we’d love to hear your thoughts in the comments!