How to Grow big watermelons in your Northern vegetable garden

How to grow big watermelons

I love melons-especially the fresh ones. To be honest I never liked cantaloupes when I was younger. They never seemed to have any flavor. Then I grew my own. They were great! You just cant beat the flavor of vine ripened.
The first thing is you have to realize you can grow the bigger watermelon varieties in Northern Gardens. Most vegetable gardeners in the North don’t try it because they think it can’t be done. In a good season this method will produce some 20 to 30 lb melons. I have not tested this with the seedless water melons but I think the results still should be very good.
I was first introduced to this system when I was working for Michigan Farmer here in Upper Michigan. They were conducting an experimental program in the Chassell Michigan area. This experiment was targeted toward commercial production so I made some small changes to adapt it to my home vegetable garden.
I have grown Crimson Sweet, Charleston Grey, and Dixie water melons very successfully. With some of the melons hitting the 30 pound range.

For soil- sand is the best. They like and need water but you don’t want them sitting in it. Some of the largest and best tasting melons I have grown were in sugar sand.

Watermelons do not transplant well. Start with Jiffy 7’s about two weeks before you plan on planting them. At planting time you want the first set of leaves open there is no need for them to be any farther along then that. The roots are very young and they will transplant well.

Well you are waiting for your plants to get started you can get ready to plant.

You can plant in raised hills, or in raised rows. I have used both-it is a mater of preference and how you have your garden structured. The idea here is to raise the soil temperature. If you are planting in heavier soil it will also help with the drainage. Rake the top of the hill or bed smooth for planting. Then water it very thoroughly.

For the next step you will need a row of clear plastic. 2 feet wide/4 to 6 mill. The heavier is better. ( DO NOT USE BLACK you will not get the results you need I tried it) The clear plastic raises the soil temperature significantly. You will get some weed growth but it will be very limited.
Run the plastic the length of your row or hill. Cover the edges with soil to hold it down and keep the air out.

Ok, you have your planting area all prepared. The plastics has been covering the ground for probably a few days and has made the soil nice and warm just like a blanket. Your plants are up with their 1st leaves open and you are ready to plant. If you are planting in hills-plant 3 plants per hill. In rows -space them 1 ft apart. Use a box cutter and cut holes in the plastic about 3 x 3 inches to plant your plant growing in the Jiffy 7. Space them equally apart in the hill or down the center of the row. After planting water each plant with a gallon of water. I water them once a week unless we are getting a lot of rain.

The final item you will need for this system are standard Hot Caps. Place the Hot Caps over your plants and cut a slit in the top for air and to water. As the plants grow you will see the leaves start to push against the inside of the caps. At this point peal them back to let the plants out so they can start to run. At this time it is a good idea to fertilize the plant while you can still get at it. I use one tablespoon triple 10 per plant or an organic equivalent. That’s about it! With a little luck and some good weather you should start to see small watermelons forming on some of the plants around the 4th of July and some ready to eat the 1st week in August.

6 Comments so far

  1. Bernard Chavers on June 19th, 2009

    This great info- thank you.

  2. elizabeth schram on July 16th, 2011

    Thorough lessons. We’ll try it next year.

  3. ANDREW OKOTH on April 13th, 2013

    What makes the fruits to grow big which nutrient as we are ad viced not to use nitrogenous fertilizes.which fertilizer should we use and at what stage of growth?.Kindly advice

  4. admin on April 25th, 2013

    I use 10-10-10 on mine and works real well.

  5. Dirk (Zone 6b Philadelphia) on March 18th, 2018

    Thank you so much for this valuable information. I live at them Philadelphia region, slightly warmer, but your method will still be of great help to me. I just have a few questions for you: (1) how large the hill should be? (2) Did you mean “7-inch diameter peat pots” by Jiffy 7? (3) Can this method be extended to winter squash, sweet melons, and cucumbers?

  6. admin on March 18th, 2018

    About 2 x 2 feet and about 6 inches high or you can run a row 2 feet wide. For the jiffy sevens use the discs that expand in water. I think the plants would be too large to use this as a season extender.
    Aalso the daylight hours would be a problem.

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