Please note all times mentioned are just a general guide to a giant pumpkins growth. There will be slight differences due to seed, location and growing conditions.
How Long Does it take to Grow a Giant Pumpkin?
This can vary a little depending on location, starting date, environmental factors. For most places and growers from seed starting right through to harvesting you will be looking at around 150 – 170 days on total. Refer to the Giant Pumpkin Planning calculator and the Life Cycle of a Giant Pumpkin below for more information.
Time from Seed Starting to Pollination of your Giant Pumpkin
From starting your giant pumpkin seed to when you pollinate your female flower you will be looking at around 60 – 70 days on average.
How long it takes for the Giant Pumpkin to Grow
On average you will be looking at around 90 – 110 days from pollination to reach maturity. Top growers want to get as many days of growth as possible out of their giant pumpkins.
Planning when to start to maximise the amount of growth before the harvest date is critical if you want the biggest pumpkin.
New Zealand Giant Pumpkin Starting Dates
For most New Zealand growers you will be looking at early to mid October to start your seeds. Colder parts of the country might start a bit later. Or they may need to look at having good early protection for the seedlings. Starting around this time will give you a harvest date of around mid to late March to early April.
Northern Hemisphere Growers
This can vary from location to location. But for a majority of growers you will be looking at starting around mid April to early May. With a harvest time of mid to late September to early October.
Check with Local Growers for the Best Times
Every location can be different and have it’s own unique environments to grow in. It pays to talk to experienced local growers to get their advice on the best times to start. They will have detailed notes of what has worked for them in the past.
Giant Pumpkin Planning Calculator
The Lifecycle of a Giant Pumpkin
For most places in New Zealand seed starting will occur during the month of October. Helping the giant pumpkin seed so it can easily germinate is recommended.
Learn about seed starting here.
Days 5 – 10
Seeds Should Start Germinating
Your seeds should germinate around this timeframe.
If using the plastic bag method mentioned on the seed starting page, place your germinated seeds into seed raising mix in a pot.
First True Leaf Appears
This is the the middle leaf found between the 2 cotyledon “leaves” which are the ones contained within the seed and aren’t classed as true leaves.
Once this middle leaf has grown you can now see which way the vine will grow. It will grow opposite this first true leaf.
Days 14 – 20
Transplant to Patch
Around this time is a bit of a balancing act. You want your seedling out growing as soon as possible, but you don’t want it to be affected by harsh conditions outside.
Make sure to harden off your seedlings.
You may need to wait a little longer until conditions improve. Early season protection is advisable.
Early Season Protection
This early protection will help your plant deal with the wind and cold overnight temperatures.
More info on early season protection can be found here.
Days 60 – 70
Around this time is when pollination of your female flowers should occur. Pollinating by hand gives you the best options and best results.
Find out more about pollinating your giant pumpkin here.
DAP (Days After Pollination) Explained
The main measurement term giant pumpkins growers use for time is DAP. Which means days after pollination.
This means no matter how many days it took to get to pollination all growers are talking about days after pollination.
This helps keep things easy to compare and keep track of.
For the rest of this timeline we will use DAP as the measurement of time.
30 – 55 DAP
Lots of Growth
During this time your giant pumpkin will grow the most.
You want to make sure you have good watering and your pumpkin has enough nutrients to grow as big as it can.
85 – 95 DAP
Your pumpkins growth will slow down a lot. It will be putting on small gains and growers will want to be doing everything that to get the most out of the plant and pumpkin.
Top growers are trying to get 100 – 110 days worth of growth out of their pumpkin if they can.
Anytime from around here will be when you will be harvesting your giant pumpkin.
Think about how you are going to lift and move it to get it weighed.