Pushing the Patio Envelope - Watermelon in Containers
(Editor's Note: This article was originally published on February 20, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
There are plenty of the refrigerator-sized, seedless watermelons on the market today. We knew we could find seeds for one that size. These melons weigh in at an average of 12- to 15-pounds, which is probably more than our patio setup can accommodate. What we were looking for was a personal-sized watermelon. If not personal-sized, then maybe couple-sized would do.
Internet searches did not turn up the vast number of choices I was hoping for. The industry considers personal-sized to be in the 3 to 7 pound range. I did find a news release announcing 'PureHeart', the "first and only personal-sized watermelon"  from 2002. So I knew this was a fairly recent development.
Although not the only one on the market in 2008, I purchased 'Petite Treat' from Territorial Seed. What I did not realize when I ordered the seeds is that this variety is not self-fertile. That is, it does not set fruit unless it has a pollinator. Inside the seed packet, there was a small envelope with 5 seeds of a different variety that needed to be planted with the 'Petite Treat'. So I dutifully planted seeds of both indoors under lights 4 weeks before our expected last frost date. They were placed on a heat mat because watermelons like warmth. In my zone 6b garden in Western New York, traditional planting time is Memorial Day weekend, so the seeds were planted the last week of April.
The pollinator came up just fine but the seeds for my main pick never germinated inside. When the time came to put plants outside, on June 2, I planted the pollinator plant and the remaining 5 seeds of 'Petite Treat'. Again the seeds did not germinate. The stem split on the one and only remaining plant, so I buried it in soil. Lo and behold, it recovered! In fact, it grew and flourished. You can see it at left on August 5, about 9 weeks after planting out. It is planted in a raised, self-watering container with a cage for the vines to grow on.
The plant bloomed and began to develop little tiny watermelons. Most of them dried up and fell off before they got very big. Usually, female flowers are the first to appear, and without the male counterparts for pollination, they just wither. One melon started to grow and didn't drop off. As it rapidly got larger and heavier, I was fearful that the weight of it would break the vine, so I made a sling out of an old t-shirt and tied it to the top of the cage (see picture at right).
Just as I was beginning to wonder if the melon would be ripe soon, a wind storm tore it off the vine in spite of the sling. Determining if a watermelon is ripe sounds dicey at best. One way is to look at the spot on the bottom and see if it has turned from white to creamy yellow. A second is to check the tendril closest to the melon and see if it has dried up. The third method which I think will take some practice; thump the melon. If it sounds dull and low it may be ripe.
It probably would have been a little sweeter or maybe a little redder if it had stayed on for a few more days. Happily, the fruit was not wasted. It was sweet enough and we enjoyed every bit of it. It was not seedless, but had fewer seeds than a regular watermelon. Since I had no idea what the pollinator fruit would be like, it was a happy surprise.
This was enough of a success, and fun, that we will do it again this year. We have not yet chosen the variety, but it will not be 'Petite Treat' because of the lack of germination. Stay tuned in the fall for more reports on my Patio Farm.
For more about watermelon, big and small, see this article by Diana Wind:
 If you would like to know more about my patio farm, clicking on this title will take you to my article,
 SeedQuest®, Company news release 4774; Boise, Idaho; August 22, 2002
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