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Deep South, USA

I went out to check on my melons. When I looked at my second oldest melon, I saw something that made my heart sink. A little black blotch about 3/16" in diameter around the blossom end. This melon looked otherwise pretty healthy on the outside- it's 12 days old, and has been growing.

Can anything be done for blossom end rot on a melon?

Even worse, this looks like the same thing that destroyed nearly every melon I had last year. I seem to remember it starting on some melons at about two weeks. I think I'm going to be sick.

I don't get it. I moved to a different spot, the soil should be better. What could be causing it?

8/2/2010 7:02:13 PM

Frankfort Oh

nothing you can do for it ,cut off ,and try for a new one theres plenty of time-but sounds to me theres somsthing missing from your soil.

8/2/2010 9:20:20 PM

Deep South, USA

Last year they were planted in red clay, with a little cow manure. Not really enough nutrition, though. This year I put them in a bed with daylilies. The bed is mainly a mixture of cow manure and sand. I thought this soil might be good enough, but maybe it isn't.

I remember one melon not having it last year, but at 42 lbs by mid September it was small relative to the potential size. I have a theory that a slow growing melon (i.e. one started when the plant was young) is not as susceptible the faster growers.

I have a small one that's about 4 1/2 weeks old, that I'm raising to see if it will make viable seed. It only weighs about 15 lbs, but it does not have this problem as best I can tell.

Besides a missing nutrient, could the wrong soil pH cause this problem?

8/2/2010 11:37:40 PM

Corryton, TN

Hang in there Yoshi. Its been hot and humid here which are great conditions for all kinds of bad things to grow. Get on top of your spray program, fungicides in particular. Weed control will help the air flow around all parts of the plant and lessen the disease pressure. Get some more sets and don't be to quick to cull. Those plants can still get you to a 100 lbs. Here's a link to help diagnose what your fighting:
http://aggie-horticulture.tamu.edu/vegetable/watermelon/diseases.html

8/3/2010 6:52:21 AM

Frankfort Oh

YES ,MOST DEFFENTLY,also ,to much water can also be the culprit,just hard to tell ,with out getting a soil test,but i like my ph around 6.9 or 7 for melons seems to be working for me the last five years,like i said just hope, for the next one, good luck

8/3/2010 9:40:54 AM

Deep South, USA

I was concerned I wasn't giving them enough water. I try to water once a day. I let them go a couple of days without a proper watering, I don't know if that had an impact. It has recently became VERY hot here, maybe over 100 degrees some days.

I've got another melon a day younger, it has a rather deformed blossom end, but I don't see any clear evidence of rot yet.

Perhaps I'm getting a discouraged a little early. I've already had one melon take BER this year. When I saw the black spot on the more recent one and realized what it was my mind flashed back to all the partially rotten melons last year, and it freaked me out. Carolina Cross (at least the Burpee 183), seem more susceptible than "normal" watermelons. I've grown an heirloom variety before, and I don't remember a single occurrence of BER.

If it is a mineral deficiency, is there any way to correct it in time to help melons yet to start this year, or does it have to be done before planting?

I was hoping to have something to take to the annual Watermelon Carnival. I've got one now that weighs maybe about 8 lbs, and the carnival is this Saturday, so looks like I'm out of luck. I can handle that though. BER is what scares me.

8/3/2010 3:29:17 PM

Corryton, TN

BER can be somewhat helped by increasing the calcium. I'd be inclined to use a LITTLE calcium nitrate if you haven't used much nitrogen recently. Calculate it by figuring 50 lbs calcium nitrate per acre per week.

8/3/2010 5:17:49 PM

Corryton, TN

Should have added do a soil test in the fall and get the calcium up at that time for next year. I've not tried to boost it this time of year but that doesn't mean it won't work. Some other calcium products may work fine.

8/3/2010 5:33:05 PM

Carrollton, Ga.

Plants Affected: Tomato, Pepper, Squash, Eggplant and Watermelon. This condition is easily recognized by the flat, leathery area on the blossom end of the
fruit - opposite the stem end. This condition is often first seen when the fruit is about
half-grown and continues as it matures. This is not a disease but a non-parasitic
disorder that is most common on tomatoes.
Blossom-end rot is the result of a calcium deficiency in the blossom-end of the fruit.
Calcium is required in relatively large amounts when fruit is growing rapidly. If demand
exceeds supply, deprived tissues break down leaving the characteristic leathery
bottom. This may be the result of low calcium levels in the soil (rare in Kansas) but
can also be caused by a sharp change from cool to hot weather, extreme soil moisture
fluctuations, drought stress, root damage due to deep cultivation or waterlogged
conditions, or excessive growth due to too much nitrogen fertilization. Blossom-end rot
due to less than adequate uptake of calcium because of a limited root system will
correct itself as the plant compensates by adding more roots.

8/3/2010 6:49:32 PM

Carrollton, Ga.

Recommendations:
1. Maintain soil pH around 6.5 as shown by soil test. Do not assume that blossom-end
rot is sure evidence that the soil lacks calcium. Other conditions that interfere with
calcium uptake can cause calcium to be demanded in higher quantities than the plant
can physically supply.
2. Use a nitrate nitrogen rather than one that releases nitrogen in the ammonium
form. Excess ammonium ions reduce calcium uptake. Also make sure that the plants
are not overfertilized especially when the fruit are small. Usually 1½ pounds of a 10-
20-10 fertilizer applied before planting is sufficient for tomatoes though sandy soils
may need monthly sidedressings.
3. Maintain even soil moisture. Mulches conserve moisture and moderate soil moisture
extremes. Even with mulches, weekly irrigation will be necessary if there is no rain.
Fluctuations in soil moisture often leads to an increase in blossom-end rot.
4. Make sure tomatoes are planted in an area with good drainage. Excess water
causes roots to smother leading to reduced calcium uptake.
5. Do not hoe too deeply. Deep hoeing can damage roots and thereby reduce calcium
uptake.

I got this info at this site: http://www.bigpumpkins.com/MsgBoard/ViewThread.asp?b=30&p=356624

doug
Jn 3:16

8/3/2010 6:54:43 PM

Carrollton, Ga.

You are right on it bro. dave. good advice.

8/3/2010 6:55:41 PM

Deep South, USA

Well, my second oldest melon is now exhibiting the signs. The blotch is just starting to form around the blossom end. I wish I could be more positive about this, but it doesn't look good.

Tomorrow will be eight weeks to the day since I set the plants in the ground. I don't know what I'm going to do. Other than my seed saver, I only have undeveloped females, and only one visible prospect. At this point, it's difficult to think anything that comes along now will survive.

8/4/2010 5:21:20 PM

Carrollton, Ga.

Yoshi,
They sell a product called stop rot for tomatoes. You might try some of that. You just spray it on the leaves I believe. It will not help the ones all ready started. But may help them coming on.
Doug
JN 3:16

8/4/2010 8:11:22 PM

Bowdon, GA

Calcum foliar spray alot of local stores have it. Also keep em watered good and evenly.

8/4/2010 11:04:42 PM

Deep South, USA

I hadn't really thought of a foliar solution. I'll give either a try if I can find it. The entire plant complex needs sprayed though, not just the areas near the fruit, correct?

Gurney's had some sort of anti-BER stuff in their catalog, but I think it had to be worked into the soil. That might be something to keep in mind for next year.

Is it possible other variations of Carolina Cross are less susceptible to BER? All I've ever grown is the "generic" 183 variety.

8/5/2010 12:02:16 AM