I have been growing giant pumpkins for awhile now and after my first year I was hooked I had an amazing time growing them and they made an awesome addition to my Halloween décor for many reasons. First of all it’s just incredible that something can get that big. I am just amazed you can grow a 500 pound pumpkin from a relatively small seed. Secondly I can pretty much guarantee that no one else in your neighborhood will have anything close. I don’t think we had one trick or treater not make a comment or take a picture. Also it gives you some insurance against would be pumpkin smashers cause they are impossible to lift on your own. Lastly the sheer size of the Jack o Lantern when you carve it allows you to do some cool things, more on that later. So put in a little work this summer and you will have the biggest jack-o-lantern on the block.
Now you can get really crazy with this or keep it very simple. My first year I did not use all the different fertilizers i will talk about here and I grew a nice 275 pound pumpkin. After that I started doing more research found a fertilizer program i liked and the following year I grew a 520 pounder and I am no where near as involved as some people. So it’s up to you but in this instructable I will show you what I have done to consistently grow 400-600 pound pumpkins.
There are a lot of places online to get supplies, I have been using www.hollandsgiants.com and they have been great. You can get everything you need there and much of the fertilizer program that I use is taken from the one that they have designed and have available on their site.
Step 1: Early Spring: Prepare the Patch
Early Spring - Prepare the patch
What you will need:
* Garden plot
* A good digging shovel
* Composted Manure
* Fertilizer (see below)
Pick a spot for your pumpkin patch that gets as much sun as possible pumpkins love full sun. As soon as the weather permits (ground thaws) you want to till the pumpkin patch. Ideally you want a space about 20 x 20 per plant but if you don’t have it you can just let the vines grow out of the patch. Mine is 20 x 40 and allows me to grow two plants.
After you till the patch grab a soil test kit from the garden center and see what you soil levels are, you are looking for a PH of 6-7. If you are outside the range the kit should also provide info on how to amend your soil accordingly.
Next, at the end of the patch, where the seedling will be planted dig a hole about 4 feet wide and 3 feet deep. We are going to pack this hole full of nutrients for your pumpkin. I add composted manure, and a Mycorrhizal Fungi (*see below) to the soil I dug from the hole, I mix it up and then fill the hole back in. Make sure to mark the center of the hole after you fill it back in so you know where to plant your seedlings when the time comes.
*Mycorrhizal Fungi is a fungi that bonds to the roots of the pumpkin plant and in exchange for sugars from the plant sends out tiny hair like roots of its own much smaller than any roots on the pumpkin plant alone. The hair like roots make the plant way more efficient at pulling nutrients from the soil.
The last step in preparing the patch is to work some fertilizer in a 8-10 foot circle around the planting site. You can use a basic 10-10-10 fertilizer from the local store and still grow really big pumpkins but to really maximize growth you want to change the fertilizer as the plants hit different stages. In the plant growth stage, they like a lot of nitrogen so you want to look for a fertilizer that focuses on the first number in that sequence. As I said I get my supplies from www.hollandsgiants.com because they specialize in giant pumpkin growing. I use Pumpkin Power 9-3-4 and Spring wake up to prepare my patch.