Yellow watermelon leaves. Why?? pic

[edweather]

I have three 18 gallon containers with watermelons in them. Using basically the 511 mix...pine bark, peat and perlite. Used some granular fertilizer a couple of times during the season (a little heavy on the P for watermelons), and also use a liquid fertilizer at 1/4 strength at every watering, which is about once per day. In the past couple of weeks, these leaves are showing some yellowing starting at the crown and working it's way outward. Have not been able to slow or reverse the trend. This is the only container that's doing this. Any suggestions? I'd like to keep the plant alive for another 6 weeks if possible. There are still 4 melons that need to mature. Thanks. Ed.

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[edweather]

Someone on another forum suggested that this is typical of iron deficiency.......will go with that for now, and try and find an iron supplement.

[Cole_Robbie]

Powdery mildew, blight, and fungus are all pretty bad for me this year. The warm winter wasn't cold enough to kill it all off.

Do you have another container with the same variety and potting mix? If you do, and it looks ok, I would consider spraying fungicide, such as Daconil.

[sprtsguy76]

My guess would be you need to increase your fertilizer application.

Damon

[edweather]

Thanks for the replies. I have 2 other watermelon containers with same mix, and they look fine. I also have several muskmelon containers, and they are ok too. I Daconiled the *bleep* out of it this am. It has plenty of fertilizer, as it's a container, I add 1/4 strength liquid fertilizer at every watering......which is every day in this hot, dry weather. Right now I'm leaning toward the blight, mildew, fungus theory. The leaves are deteriorating fairly rapidly. The affected leaves are dying, and getting brittle and crunchy. I've got 4 melons in this container that are definitely not ripe yet.......trying to hang on for dear life.

[Cole_Robbie]

I'm in Illinois, but it is obviously very hot and dry here, too. I think my field of pumpkins and melons has a lot of powdery mildew, which is typically associated with overly wet weather. However, there is a strain of powdery mildew that typically lives in the desert southwest, and it thrives in hot and dry conditions. I think that's what I have, and maybe you too.

Daconil is meant to coat and protect the healthy leaves you have left. Two other treatments that I have read about, but not tried, are milk and peroxide. The milk is a 10-20% solution of skim milk and water. I think it works by changing the surface ph, making it hard for the fungus to survive, but that's just a guess. Hydrogen Peroxide will kill anything bad that it touches. Dilute the drugstore peroxide in 2-3 parts water.

Your other options would be fungicides with either a copper or a sulphur base. You could try all of these in a five-day rotation.

[edweather]

Thanks Cole.....can't wait to try the skim milk, and peroxide thing too.