zucchini rotting on the vine

lilionJune 24, 2007

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.

Thank you for reporting this comment. Undo

According to this thread...


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

    Bookmark   June 25, 2007 at 12:12AM
Thank you for reporting this comment. Undo
gumby_ct(CT it says Z5)

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.


    Bookmark   June 25, 2007 at 1:23AM
Thank you for reporting this comment. Undo

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!


    Bookmark   June 25, 2007 at 9:32AM
Thank you for reporting this comment. Undo

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.

    Bookmark   June 25, 2007 at 10:26AM
Thank you for reporting this comment. Undo
gumby_ct(CT it says Z5)

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.


    Bookmark   June 25, 2007 at 11:04AM
Thank you for reporting this comment. Undo
gellfex(6 NJ)

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.

    Bookmark   July 30, 2007 at 1:00PM
Thank you for reporting this comment. Undo

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.

    Bookmark   June 4, 2011 at 10:03AM
Thank you for reporting this comment. Undo

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.

    Bookmark   July 7, 2011 at 8:08AM
Thank you for reporting this comment. Undo

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.

    Bookmark   July 8, 2011 at 3:40PM
Thank you for reporting this comment. Undo

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?

    Bookmark   July 1, 2012 at 10:05PM
Thank you for reporting this comment. Undo

Having read the article I mentioned to my wife that the Zucchini rotting was probably due to calcium deficiency. She suggested calcium tablets, so I have dissolved two tablets in water and fed it to the plant on two occasions.and it seems to work.

    Bookmark   July 14, 2014 at 4:04PM
Thank you for reporting this comment. Undo
nancyjane_gardener(Zone 8ish North of San Francisco in the "real" wine country)

I was in Hawaii and my daughter was in charge of watering end of may, first week of june. She kept the plants alive.....just. The first several zuks showed signs of BER, then when I got home and consistant watering started happening, I started getting PLENTY! (want some?)
I know pollination wasn't a problem, cause with my herb garden right across the path and herbs interspersed within the garden I have PLENTY of bees!
And GUMBY "Have the words soil test before" sounds a bit rude to me. It's not always possible or affordable! I have 10 different raised beds that may have 10 different soil mixtures in them. CA no longer does the cheap soil tests and sending off 10 soil samples could run a couple hundred $$! That doesn't make my veges more affordable! Nancy

    Bookmark   July 14, 2014 at 8:51PM
Sign Up to comment
More Discussions
Need advice on setup
I am in charge of a community garden at my place of...
Brandon Smith
Skirret and Sea Kale
Can someone tell me where I might buy Skirret and Sea...
aftermidnight Zone7b B.C. Canada
Why is Zucchini Stem Splitting?
This is my first year growing zucchini. It's in a container...
Cliff Pruitt
weed or seedling
In the area of this seedling my daughter put radish...
what varieties of watermelons are you growing?
what varieties of watermelons are you growing?
Sponsored Products
Chard Multi-Chopper - MC-B
$44.06 | Hayneedle
PLAY Pet Lifestyle and You Garden Fresh Toy Set - PY7010BSF
$37.91 | Hayneedle
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™