Watermelon Failures

My attempt to grow Sugar Baby watermelons in a container was nowhere near as successful as the experience I had with Early Moonbeams. Since I seemed to start a little too early on the previous attempt, I started from seed indoors later with this one than I normally would, about 2 weeks before what is said to be the last frost date for my area. The seedlings were slow to start and did not grow as fast as I hoped they would. When one got to about a foot long, I decided it was time to transplant it outside.

It took a long time for this vine to grow past this length. It was a good month before I had to trellis it.

The container I choose was a self made self watering beast constructed from a pair of 18 gallon Rubbermaid totes. This gave me about 10 gallons of soil with a 6 or 7 gallon water reservoir which I rarely had to fill. Especially when the plant was small. After transplanting, growth appeared to slow and I blame that partly on my soil mix. I was reusing the previous years potting soil which was mostly peat and to it I added some vermiculite and pearllite and a large portion of store bought compost. What seemed like a good idea, probably led to failure number one: compacted soil. I used too much compost which led to a very heavy potting mix. The compost was likely of very poor quality. That's the problem with buying it in bags - you never really know what you're getting. I should have added much more vermiculite.

A few good bamboo polls and some cable ties are all that's need to make a sturdy trellis.

We had a particularly cool spring also. It was never frosty but consistently cool. There were a few nights where strong winds forced me to bring everything indoors. It was a good month before my watermelon vine appeared to make any progress and I was starting to get concerned that the plant just wasn't going to produce.

This is a week after pollinating by hand. Sometimes they get to this stage and die off but typically, when the stem grows long and down, they're turning into watermelons.

But eventually it started to spread. The single vine branched a few times and by mid season I was getting a number of female flowers. These I had pollinated with what at first appeared to be promising results. Three hand pollinated female flowers of six formed melons. There were more female flowers but I figured three was enough. I noticed that once the third started growing, the second seemed to stop growing so I snipped off the third melon, deciding I'd rather have two decent melons rather than three that sucked.

It was around that time that I started to notice some of the lower leaves on the plant turning yellow from the inside out. I couldn't see it easily at first but under really close observation I could see a number of very tiny insects covering some of the lower leaves. Some internet research revealed my problem: spider mites. And they were slowing moving their way along the vines, sucking the life out of the plant as the went. The leaves on which they settled would turn yellow then brown. They would have a rough stippled texture before becoming brittle and dry. The backs of the dead leaves were covered with a very fine webbing. And it was spreading practically before my eyes.

To combat the problem I started spraying the backs of the leave with water using a spray bottle. It only took a few minutes and about half a gallon of water every other morning . I was able to slow the spread of the mites but it was not a permanent solution. I was not able to completely eradicate them, only slow them down temporarily.

This is a week after pollinating by hand. Sometimes they get to this stage and die off but typically, when the stem grows long and down, they're turning into watermelons.

By this time my vines had grown to a good length and the two melons were growing well also. In the past I had used bamboo sticks lashed together with string as support for my plants. Every season I plan to construct elaborate trellis systems with platforms on wheels. But I always revert to a 'cheaper is better' and 'whatever works' approach. I used my bamboo sticks again this year but this time I used plastic cable ties to hold everything together. Bamboo sticks are tapered and the long poles I use for vertical uprights were tapered enough that with the big end in the soil, a tight cable tie just got tighter as it slide down the pole. So using the cable ties made for a very solid bamboo trellis. I also inserted the two poles into the soil at the very edge of the container and drilled a pair of holes through the container on either side of each pole. I then passed a single cable tie through the holes and tightened it around the pole, anchoring it to the sides of the container. This helped prevent a lot of trellis movement.

This was about as big as my sugar baby watermelons got. About the size of a grapefruit. This is a month and a week after pollination.

The trellis worked out really well this season but the vines did not grow as long as I hoped they would. The leaves got big and dense but the plant just didn't want to grow. As the melons grew, they quickly went from light green with stripes to an overall very dark green colour, just like you'd expect from a sugar baby melon. But once they reached large apple size I noticed they were both lopsided with the distance from top stem to bottom dimple being shorted on one side. A likely cause: inconsistent pollination. Pollination isn't just about getting male pollen somewhere in the female flower. It's about getting the pollen spread consistently across all areas of the female stigma. If the flower is inadequately pollinated, you end up with lopsided fruit growth.

This was about as big as my sugar baby watermelons got. About the size of a grapefruit. This is a month and a week after pollination.

We were away for a couple of weeks in the middle of August and even though I had someone come by to water the plants, I didn't have them spray off the spider mites. I felt that was asking a bit too much. I had a pretty good feeling that this would mean the end for my sugar baby melons and it almost was. The mites flourished while I was away and turned over half the leaves yellow. But the melons continued to grow to about the size of grapefruit. I returned to my regular spraying of the leaves but the mites had spread too much. I'd spray them down one morning and the next they'd be back in full force so I gave up. It was almost September and I didn't think there was anyway my lopsided melons were going to reach a mature size before the spider mites killed the plant completely.

My vine didn't grow much more than this. The trellis was more than tall enough at 4 feet high and about 4 feet wide.

The melons pretty much stopped growing at that point. The ends of the vines dried up and stopped growing. I left the melons on the vines for a few weeks to at least give them a chance to mature. They barely weighted half a pound. I cut one open to see how mature they had gotten. They were mostly white inside with lots of immature seeds. I scoped out some of the red flesh and it certainly tasted like watermelon. I learned quite a bit from the experience and if and when I grow watermelons in containers again, I will use the self-watering container, start them earlier, be more thorough with the pollination and inspect the leave more often for pests. I've also got to be more careful about what goes into my potting mix. Some things are beyond your control but if you carefully manage the things that are, you'll have less problems to slow you down when you need to deal with the more difficult problems.