Timer not working? Or on too long too often? Tho I thought watermelon liked hot, dry summers? Double check that .35 rain claim? Roots found a well? I give.

Splitting is caused by internal pressure and only 2 things that I know of can increase that internal pressure to the point of splitting. 1. gas build up from internal disease infection and 2. water. And water is hands down the most common cause.

"My garden waters itself, thanks to soaker hoses that run on a timer."

So the plants are getting watered whether they need it or not? So all the plants are getting the same amount of water even if a particular plant needs more or less? How long and how often do your hoses run?

Sorry but gardens can't water themselves. ;-) Soaker hose can spring leaks, get kinks, timers need frequent changes, plants need different amounts of water as they mature - sometimes more, sometimes as with melons much less. Plants tell you not the timer when they need water and when they are drowning (see the yellow leaves in the photo).

How often do you stick your hand deep into the soil to check out wet it is or isn't?

If there are no signs of internal disease in the split melons then I'm sorry but the odds are they have been exposed to much more water than they could handle and so exploded.

Dave

I'm concerned about my melons. So far, so good, but we had 1" of rain the weekend of the 21st, and 5" this past weekend.

Digdirt2 - A few answers: the timer is set to start watering the zones every day at 8:00 in the morning. I have 6 zones. On each one I have connected a soaker hose. There are 2 zones that water the melons - cantaloupe and watermelon. One of them was set to run for 5 minutes, the other for 6.

I ran each of these 2 zones manually for a minute this morning so I could detect any leaks. None.

I have been fighting spider mites like crazy in my garden. Tomato plants, beans, and watermelon seem to be hit the hardest. They don't seem to bother the cantaloupe much, even though the melons are side by side and by this time of the summer, the vines intertwine. Cucumber beetles have also been a common visitor lately. I have used Murphys Oil Soap and Horticultural Oil Spray for the mites and Carbaryl once for the beetles.

I took a couple more pictures of the vines this morning.

The good news is that in a day or two the first and biggest will be ripe.

The cantaloupe vines still look lush and green.

the timer is set to start watering the zones every day at 8:00 in the morning. . One of them was set to run for 5 minutes, the other for 6...

I use soaker hoses on my melons too but use them only during a dry spell and never if it rains. When I do use it I'll turn it on for about 90 minutes to allow for a deep watering. Your daily use could be the answer to your splitting problem but 5 minutes seems hardly enough to get the surface of the ground damp.

Agree that the time you are running them and the frequency is way off.

First daily watering is never recommended for in ground plants as it only creates totally water dependent plants with shallow root systems. Those plants are very prone to many issues, including pests, nutrient issues since the roots seldom go deep enough, disease, and splitting. Since the surface dries out so quickly and there is no deep water for them to rely on. So the plants are stressed between overly dry soil follow by a influx of mositure that they suck up far too quickly. Plus you say you have 2 lines feeding the melons.

Second, as vgkg said soaker hose are normally run for hours at a time not just a couple of minutes. They are a trickle water delivery method and can require up to 1 hour or more when tested to deliver 1" of water depending on your water pressure. My average run time with my soil is at least 90 minutes and in some areas 2 hours to provide adequate deep watering. And they only run once a week except during a really long 100 degree plus period with no rain. Then it may be 2x a week.

Your plants appear to be very nutrient deprived in the photo but that can often be due to the photo color alone. Spider mites wouldn't have affected the splitting,

Dave

To the oper....Those yellow mottled leaves indicate something.

Spider mites.