I needed space for my tomatoes, aliums, and other cucurbits, so I scoured the internet. Somewhere, I found a picture a guy had of a forest somewhere--with pumpkins growing in a tree. The vine had apparently climbed the tree, and set fruit high up in a tree. There's also this news article about the Greenfield, Iowa couple who found a pumpkin growing in their pear tree.
So I thought to myself, if they can grow in trees, why not up and onto the roof of our garden shed?
Step 1: Have the Right Pumpkins, Soil, and Time
it will be much more difficult to train without risking breaking it.
Additionally your choice of pumpkin should be vining, and of a small or medium variety. While growing a record breaking pumpkin
on your roof may sound like a neat idea, it could cause water to pool on your roof, causing damage to shingles. The other reason you need to keep the pumpkin size down is that you have to get it down some day.
A good rule of thumb is this: Grow pumpkins no larger than the heaviest thing you can carry up and down a ladder, without assistance. A record-breaking pumpkin could break you.
I selected Connecticut Field Pumpkin, which is the classic "Jack-O-Lantern" pumpkin, and of a medium weight (25-50 lbs). Being medium sized pumpkins with long, vigorous vines, they're well suited to this sort of trellis.
Additionally, you may wish to use landscaping fabric and mulch around the base of your pumpkins--all the way up to the side of your structure. This prevents grass and weeds from growing in between your plants and the building, and controls insects
Step 2: Effect Necessary Repairs
Pictured is a female flower. You don't want to lose these girls, because they get big, orange, and delicious in pie. The leaf next to it was broken off accidentally. Breaking leaves and stems is something that should be avoided at all costs. Hence most of your construction should take place while the vines are young.
Step 3: Tools and Materials
- Hammer, Saw, general carpentry tools
- A staple gun, such as that used for insulation
- A ladder of sufficient height or a ladder of nearly-sufficient height, and an assistant
You will need to beg, borrow, steal, or recycle the following
-Wire fencing material
-2 1/2" galvanized nails
-Jute Twine or similar
Step 4: Constructing the Trellis
I used bent over nails to fasten the wire to the trim, and 1x2s as my staple gun is only fit for insulation installation and not the sort of thing that can nail fencing material to posts. A helper is handy at this point.
Step 5: Training Your Vines -- Part I: Up the Trellis
Try not to break stems. They tend to be brittle in older plants. If all the leaves aren't facing towards the sun, don't worry. Phototropism will fix that in a few days. Maturing fruit will need additional support if it develops on the trellis. Fortunately since I have an existing structure behind my trellis--I can easily attach slings to support fruit. If it develops on the roof, you win!
Step 6: Training Your Vines -- Part II: Beware the Eaves of May
Pumpkin vines cannot grow to space, unless you own a rocket company so I had to correct this matter. Their stems are strong, yet brittle, and will collapse if left unsupported by things like the ground. Therefore one must gently bend the spaceward-stems, and anchor them to the roof of the victim building.
The part of the vine unsupported, and growing upwards, needs to be around a foot long, so that you can gently bend it towards the roof. Any shorter and you risk breaking the vine. Any longer, and the vine might break itself for you. Pumpkin vines grow very, very fast, and so you have to be quick here--even if it means going up on a roof at night with twine & stapler in you hands, and scissors clenched in your teeth like a really weird pirate.
Step 7: Training Your Vines Part III: Anchoring, and Maintenance Pruning
I used the same staple-and-loop system that is shown in the previous step. A short length of twine is securely stapled to the shingles, and then loosely tied around the vines it needs to anchor in place. So far my vines have survived 40 MPH winds without any trouble whatsoever. You'll probably need to get up on the roof again.
For general maintenance pruning, try and keep your vines on the trellis and roof. Clip off any growth tips that are going where you don't want them to go. This should be done when the errant tips are young, to save the plant's energy. Thanks to their double-vascular system, pumpkin vines are extremely vigorous, and we want pumpkins on the roof--not on the ground!
When you add more anchors, try and guide your vines towards the crown of the roof, keeping them away from the edges.
Step 8: Go on a Panty Raid, and Help Flowers Make Sweet Love
On my vines, most of the male flowers developed at a lower level than the female flowers. Thus I very carefully clipped the pollen laden anthers out of the male flowers (I have heard you can eat the blossoms, if you fry them), and gently rubbed them onto the anthers of the female flowers.
Male pumpkin anthers look a bit like those miniature corn things you get in stir fry bags at the supermarket. Don't be afraid to clip off female fruits that would have developed in an inconvenient location.
Does hand pollination work? Look at the picture. The pumpkin hanging in the generously "donated" hosiery is only about two weeks old. That is your supermarket-sized apple, for comparison's sake. I suspect this pumpkin will need additional support soon.
Step 9: Admire Your Use of Previously Unusable Space, Brag to Friends and Neighbors
So what was it that the Mythbusters say? Ah yes. Myth Confirmed!