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zucchini rotting on the vine

Posted by alys Zone 5/6 - MO (My Page) on
Sun, Jun 24, 07 at 23:59

I'm not sure if rotting is the right word for it, but I have had several zucchini that will grow quite large in length, 6 or 7 inches, and be quite large at the base, about as big around as an egg, but the large part is only about 2 inches up. The remaining 4 or 5 inches will stay rather slim and will turn mushy and then go yellow and rot away starting at the blossom end. They never get quite big enough to eat, although I have gone ahead and picked some before they get too mushy, cut off the soft part and use the rest. Can anyone tell me what would cause this? Thanks.


Follow-Up Postings:

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RE: zucchini rotting on the vine

According to this thread...

http://forums2.gardenweb.com/forums/load/cornucop/msg071354436393.html

your problem is a lack of pollination caused by a lack of bees.


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RE: zucchini rotting on the vine

I thought the fruit would fall off or be deformed with incomplete pollination.

To me it sounds more like Blossom End Rot (BER) caused by poor calcium uptake within the plant. The soil could have adequate calcium (confirm with soil test) which may not be getting into the plant because of too little or too much water. Yea the happy balance thingy.

Use your finger to test the moisture in the soil. Just keep in mind where the plant it taking in nutrients could be 3-4ft away from the stem.

Lime takes months to work in the soil. But you could try adding powdered lime 4-5 feet circumference around the plant, water in well then mulch around the plant to keep moisture level consistent, water again.

I've never tried it but you could try a foliar spray on the leaves with milk (or half/half) & compost tea if you have it to see if that helps. The milk is sposed to help with powdery mildew too.

If you don't use compost/manure tea, I would certainly start using it to water the plants.

Just keep a journal of what you have tried, cuz if you are like me, you will forget what you did then you won't know what worked or what didn't.

HTH,
Gumby_CT


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RE: zucchini rotting on the vine

  • Posted by alys Zone 5/6 - MO (My Page) on
    Mon, Jun 25, 07 at 9:32

I don't really think it's lack of pollination either since I have some tiny ones that turn and fall off too and those would be that. These get long, but only big around on the stem end and then the skinny blossom end starts rotting away. I did some searches on BER and I do think that may be it. Some of what I saw talked about too much nitrogen in the soil makes all the calcium go to the leaves and not enough to the fruit. Since I planted in pure compost, maybe it's just too rich? I've mentioned before that the plants are HUGE, with leaves over 18" across.

I think next year I'll mix topsoil into the soil. While it sure made stuff grow, I think I know now why pure compost isn't the best.

I'll try that milk thing too. Can't hurt!

Thanks!


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RE: zucchini rotting on the vine

Alys, it depends on what is in the compost. If the compost is created from at least five different source materials, then it is a minimally healthy blend. If you are only using compost from limited sources, then the plants do not hae a balanced diet. Compost will never be "too rich", unlike commercial fertilizers which can burn the plants, etc. With compost, the plants take what they can use, it's as simple as that.

Carrots are good for humans but if the only thing you ate were carrots, your skin would turn yellow (this phenomenon, which is called Carotenemia) and you'd have severe vitamin deficiencies from lack of eating from other sources.

The problem may not be a calcium deficiency, BER can occur from over watering as well as under watering. High humidity can cause BER. Over use of commercial fertilizers over the years can cause BER. Planting the wrong variety of squash can cause BER. Next time look for resistant varieties.


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RE: zucchini rotting on the vine

I can't imagine finished compost being overly rich in N.

Compost should be perfectly balanced and I start my seeds in "My Compost" but I know what goes into "My Compost". You should not have any problems growing in pure compost, Ma Nature does it every year.

Have you heard the words soil test before? Sure would save a bunch of frustration, time, and money. But as mentioned water or lack of water can also contribute to the problem. Water moves calcium through the soil.

Squash and tomatoes seem to be sensitive to BER, if that's what it is.

Mulch, Mulch, Mulch, Leaves, Leaves, Leaves. Shredded is better but not required.

HTH,
Gumby_CT


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RE: zucchini rotting on the vine

I say it's pollination. There's always a certain percentage of female blossoms that simply wilt before blooming, but what you describe is a pollination problem. Try hand pollinating and see if you lose any after that.


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RE: zucchini rotting on the vine

could be blossom end rot, or sqaush bugs/vine borer. I had the same problem. thought it was blossom end rot so i put egg shells, mulched, etc. But it turned out to be a pest that is inside the plant. You will be able to tell if u google it and see the tell-tale signs.


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RE: zucchini rotting on the vine

I don't think the rotting zucchini is due to lack of pollination. If the blossom doesn't get pollinated it doesn't produce fruit at all.


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RE: zucchini rotting on the vine

I live in the San Bernardino area of Southern California. It has been very hot and very humid over the past week or two.

I just removed several zucchini, 2 to 3 inches long, with BER. Mine are growing in Earthboxes with a filtered automatic watering system. I added the appropriate amount of dolomite and fertilizer to the organic soil prior to planting and have taken several healthy zucchini from the 2 plants.

I have tons of bees, and only my zucchini were affected. In my case I don't think it's a pollination problem, yo-yo watering or a soil deficiency. It has to be the extreme muggy weather we've been having.


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RE: zucchini rotting on the vine

I live in Kyoto prefecture, Japan, and am having exactly the same experience with zucchini as ALYS. It is rainy season here and mild. The leaves are huge and there are a number of flowers - many of which are not forming fruit which I guess is a pollination issue - those that are forming - the ones that have firm flowers - are fine. Those which have rotten flowers are, quite logically, rotting from the flower end. Despite any soil deficiencies, I think this is likely to be simply a issue of prolonged wet weather?


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