Nutrient Deficient Zucchini?

[Cola82]

I don't know if anyone is following my gardening thread closely enough to help me with this so I'm copying what I wrote to this forum.

I would appreciate help figuring out what happened to my yellow zucchini.



The white spots you can faintly see are actually dried milk droplets from the milk spray, which I've only half heartedly applied since this cultivar is resistant to PM. I've focused my energy on the butternut squash, which looks amazing.

Given how some of the other plants are also struggling, too, I think what's happening is that the compost I bought is junk. Not literally--they promised me it didn't have any manure in it--but in the sense that it doesn't have many nutrients in it. I mixed it with a cheap veg/garden soil that drains ridiculously fast. I've noticed everything potted in it exclusively is really stunted. I would use my own compost, but I don't have room in my small yard to create any.



I haven't tried purchasing any fertilizer yet. The only thing I have on hand are 10-10-10 crystals that you sprinkle on the surface, but I don't top water so they have limited effectiveness. I've been working coffee grounds into the soil and I'll try some epsom salt, too, but I'm not sure what kind of nutrient deficiency I'm looking at, if any.

I know it's not bugs--there aren't even any aphids on it like there are on everything else. I checked for spider mites and it's clean.

Please tell me what you think.

I appreciate any help.

[Lindsaylew82]

Hi!
I think Chlorosis.

Earthworm casting tea is really awesome for fixing this. You could feed your plant something with a lower nitrogen content (first number) and a higher phosphorus content (second number. I like bone meal, but it's not very instant. The casting tea works pretty quick, though. I don't have my own worm box, but black gold makes a really great worm casting line.
https://blackgold.bz/products/fertilizers/

[imafan26]

Compost and manures are good for building the soil but the actual NPK is not very high. Your soil drains well that is good. Manure tea, fish emulsion would give it a nitrogen boost. The plants are small and looking a little chloritic. I see that more when the pH is on the upper end of the spectrum. A lot of composts can be up around 8.0. At higher pH values nitrogen gets lost faster and micro nutrients become less available and you get small chloritic plants. the nasturtium leaves are on the smallish side but they look otherwise good and nasturtiums don't mind a higher pH.

For some inexplicable reason, I have noticed the commercial composts have been "balanced' with the addition of dolomite lime. I usually have a hard time finding a compost that does not do that. I balance that with the addition of iron or sulfur, since I know the compost I get has a pH 7.8. Only one of my plots has a pH 6.4, another has a pH 7.4 and the other has pH 7.8. In the more alkaline soils root crops do better and the cabbage family. The acidic plot makes lots of greens and not much root, so I grow the plants that like more acid and nitrogen hungry like the corn, zucchini, tomatoes, peppers, green onions, cutting celery, beans, and peas. Lettuce grows fine in either one, except I have slugs and snails that devour the lettuce overnight in the acidic plot and about a million thrips in one of the alkaline plots. I do put out slug bait but I can't spray for thrips without killing predators and the neighboring plot is full of weeds. So, is mine I live with it. I still get enough to eat, even though it isn't always pretty.

[Cola82]

Thanks so much you two! I'll let you know how it goes.

[rosag6]

That's interveinal necrosis (dead tissue, not just yellow) on old leaves--so probably Magnesium deficiency... I am having the same problem

[webmaster]

That's interveinal necrosis (dead tissue, not just yellow) on old leaves--so probably Magnesium deficiency... I am having the same problem

Thanks for your suggestion!
I appreciate your taking the time to post that.

[imafan26]

I had multiple deficiencies with my cucumbers. My cucumber leaves looked similar to yours. It took a long time to figure out the calcium deficiency. I had never seen it before. These were grown in containers with organic fertilizer. The organic fertilizer was not complete.

It also caused problem reusing the soil. I had the potting soil tested. pH was low 5.2, phosporus was very high and probably caused some of the nutrients to become unavailable. Potassium, calcium, magnesium and iron was low. Zinc was ok, but because of the other nutrient imbalances, zinc was not readily available. The only deficiency that it did not show was iron. Cucurbits deficiencies are similar.

Your zucchini looks a lot like the severe calcium deficiency. It could be a combination like mine was. The late stages of magnesium deficiency would also look like that as well.

If you are growing in a new soil mix, Haifa group also gives information on nutrient management. Cucumber and zucchini should be similar.

Test your soil to see what the imbalances are.

https://www.haifa-group.com/cucumber-0/ ... s-cucumber