Introduction: Grow a Square Watermelon

Picture of Grow a Square Watermelon

This is really, really easy to do. (Note: you may be able to use this technique to grow other stuff in the form of a square ( actually in the form of a cube) and apply the general idea to other shapes.)

Step 1: Materials and Tools

Picture of Materials and Tools

You need 6, 8" square, 3/8" thick (or thicker) sheets of polycarbonate plastic. (Lexan)

You will need 4 gate hinges and 2 hinged clasps with flat head machine screws and hex nuts plus at least 8 or more 1" to 1-1/2" long, thin wood screws and possibly a 36" length of angle iron or aluminum angle (cut to 8" lengths to yield four pieces) if you have thinner polycarbonate, a power drill and hole saw, and a hand saw or power saw such as a jig saw.

Step 2: Cut the Stem Pass Through

Picture of Cut the Stem Pass Through

In the first sheet drill a 1" diameter hole in the center with the drill and hole saw. Then, using a hand or power saw, cut 2 parallel lines from the hole perpendicular to one edge of the sheet and remove the material between.

Step 3: Add First Set of Hinges

Picture of Add First Set of Hinges

Use a box to rest the left side sheet, place the top sheet left edge over the left side sheet edge and fasten the sheets together as shown in the diagram with 2 hinges.

Step 4: Trim the Inset Sides

Picture of Trim the Inset Sides

Measure the width of the sheets and trim each side of the the inset sides by this width.

Step 5: Fasten Sides

Picture of Fasten Sides

The edges of the inset sides will have to be trimmed the thickness of the poly you use so they can be inset and still keep the box square. Trimming these edges is probably the hardest step.

Drill pilot holes through edge of the left and right sheets into side sheets between them to accept the wood screws. Use 2 or more screws per joined edge. A piece of angle iron or aluminum can be used to beef up the corners if the polycarbonate you have is too thin. (If the poly is too thin, however, it may bulge.)

Step 6: Do the Bottom

Picture of Do the Bottom

Place the box on its top, add the last sheet for the bottom and secure with hinges as you did the top.

Step 7: Add the Clasps

Picture of Add the Clasps

Clasps go opposite the hinges on the top and bottom sheets.

Step 8: Usage

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Plant watermelons. As soon they begin to grow large enough to place them in the box with the stem through the slit and hole, do so. Remove when ripe.

Step 9: Addendum: How to Grow a Watermelon

Picture of Addendum: How to Grow a Watermelon

How to plant your watermelon

Watermelons come in about 1,200 varieties worldwide, divided according to season and seed production. China is by far the worlds largest grower of watermelon. Growing time is from 70 to 85 days for all varieties and growing season begins when all danger of frost has past. Watermelons can be grown indoors anytime of year but require extra amounts of space and constant temperature between 80 and 85 deg. F.

Seeds for seedlings to be transplanted outdoors may be started indoors 3 weeks before transplanting outdoors. Seeds are planted one inch deep in groups of 3 and seedlings thinned to the best 1 or 2 for planting. You can use this method with peat or potting soil to start seeds indoors. Seedless varieties must be planted alongside seed producing varieties in order to pollinate and set the fruit.

Hills for single transplants are spaced 2 to 3 feet apart while double transplants are spaced 4 to 5 feet apart. Rows are spaced 7 to 10 feet apart.

How to tell when your watermelon is ripe

Use black plastic to cover the hills and rows and plant through the plastic. Drip irrigation is sometimes used sparingly in cooler climates.

Use a combination of the following indicators to determine when your watermelons are ripe:

1. light green, curly tendrils on the stem near the point of attachment of the melon usually turn brown and dry;
2. the surface color of the fruit turns dull;
3. the skin becomes resistant to penetration by the thumbnail and is rough to the touch; and
4. the bottom of the melon (where it lies on the soil) turns from light green to a yellowish color.

Many watermelons do not emit the proverbial "dull thud"when ripe. For these, the dull thud may indicate an over-ripe, mushy melon. The above indicators for choosing a ripe watermelon are therefore much more reliable than "thumping" the melon with a knuckle.

Source: University of Illinois Extension Service


jeffcole (author)2015-04-17

They look like minecraft fruit :)

Goomy bear (author)jeffcole2016-10-31

Thought the same thing! xD

JackF40 (author)jeffcole2016-05-18

Thought the same thing! xD

kcls (author)2010-06-09

I can see it now- instead of a watermelon, grow a pumpkin in a cube shape. Then, carve a Domo-Kun face on it. Voila! Domo-Kun Jack-O-Lantern.

I've got dibs on the 'ible.

omnibot (author)kcls2010-06-09

Do it!

kcls (author)omnibot2010-06-09

Gotta wait until I have a garden to grow it in! Living on a boat and all, I don't have a very big yard :D

Hiroak (author)kcls2010-06-09

I'm on a boat Motherfu Ha ha very orginal I know I lived on a boat, the sail type for 2 years and build floating garden boxes out of blue foam board. I had a slip larger than my boat so I just attached them to the dock. Then I got a bigger boat and build two above ground planter boxes on the deck. I even tried to grow an orange tree, to combat the scurvy but I live in Alaska.

JackF40 (author)Hiroak2016-05-18

OK, I know this is off-topic, but wow. That is an interesting life. xD

emma.bigknife (author)kcls2014-10-17

You just have to be imaginitive about where to grow. I have seen people grow things on walls and roofs. Doing this also cuts cooling and heating costs.

ant not aunt (author)kcls2012-08-04

you don't need a garden i grew a pumpkin in a large pot and trained the vine to a railing. when fruit formed i used pantyhose to support the weight.

corey_caffeine (author)kcls2010-06-09

you do, it's just REALLY flooded

xenor (author)corey_caffeine2010-06-09

So... rice?

aseaheru (author)xenor2011-01-02

salt water.......o_0

corey_caffeine (author)xenor2010-06-10


aseaheru (author)corey_caffeine2011-01-02

put it on the mast head. o_0

DarmaL (author)2016-04-29

Oh, they sell square watermelon seeds in Aliexpress ... ha ha ha

austinwebdesign (author)2016-04-27

no way. this is crazy.I wish I liked watermelon

obsidianjaguar (author)2016-01-05

I saw a you tube from a russian show about the japanese square watermellon .. in that one the mellons were over a hundered bucks each , but were inedible and not good inside ( yellowish flesh) hy?

davidbarcomb (author)2014-11-26

I saw this in a Japanese show and it was really nice. Great instructable

scott.gosa (author)2014-07-27

$80 for materials? Geez!

fashboy (author)2014-01-20

'This is really, really easy to do.' OMFG SO EASY

Not4Guy (author)2013-09-22

I wonder if this could be doing to shape a pumpkin into a skull for witches hat?

sinnae (author)2013-09-03

I feel like this would introduce a ton of moisture-induced rot unless plenty of ventilation is drilled into each panel.

elkrivermr (author)2013-06-09

how do you deal with rain and condensation?

porcupinemamma (author)2013-06-06

Would a box work? I do not have the ability to make your cool invention

ant not aunt (author)2012-08-04

i bet you don't need all the hardware. you can probably use big rubber bands to hold the form in place.

Nukeman (author)2012-07-10

The Lexan to build this costs about $80. Will plywood work?

GreenMeUpScotty (author)2012-06-04

Does the Box have to clear and made out of plastic?

myakka (author)2012-05-26

How about triangular( pyramid) shaped ones. Or dodecahedrons!

myakka (author)myakka2012-05-25

Or how about make the entire alphabet

kjohnson40 (author)2011-10-15

we grew a square honeydew (by accident) it was in a cement block we used to "fence" the garden with.

tinker234 (author)2011-06-19

wow i love this

moonchylde (author)2011-06-18

I wonder if this would work with tomatoes, or if the boxes would be too heavy for the vine to support. Another thought I had was two-liter pop bottles (watermelons with feet; they'd also be good for watermelon spikes :P), though I'm not sure if the fruit wouldn't split the plastic. I might experiment with this.

geoslim13 (author)2011-03-17

to quote Eurotrip "Gotta love that exchange rate!"

yiumanwan (author)2008-06-07

does it taste diffrent like sweetness

aseaheru (author)yiumanwan2011-01-02

soil might change the taste, also chemicals, water, but thats all that might change the taste

nope exactly the same exept shape

ReCreate (author)yiumanwan2009-10-07

Wow how did you make large text??

Derin (author)ReCreate2009-11-01

<h1>like this i guess</h1>

axlrose (author)2008-02-22

That is so awesome how you can grow square watermelon and sell them for $82.00

bFusion (author)axlrose2010-06-10

Yeah, but you have to live in Japan for that to happen. Everything, large fruit especially, is expensive over there.

aseaheru (author)bFusion2011-01-02

1st of season/perfect are more expencive

awesomeman2468 (author)2010-12-26

in a historical note I believe this was started in china and in most recently the chinese made melons with the mascots from\for the bejing olimpics

indestructibleguy (author)2010-06-09

would it work with apples? then you would cut a small cube from inside an fill it with caramel and chocolate syrup... hmmm....

I think if you made this box and put a pipe on the middle,you'd have a holed fruit of which you can stuff.

will the fruit grow around it?

It should.I've seen Mickey shaped ones in Disneyland too.

natalie0031 (author)paperclip322010-11-14

I think those are regular apples with marshmallows for ears.

paperclip32 (author)natalie00312010-11-15

I said that further down.

hawkfrost64 (author)2010-07-22

you can use a cinderblock.

About This Instructable




Bio: I'm an Emu. As a young chick my parents use to feed me watermelon and I loved it so much everyone nick named me ... More »
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