Burning cucumber leaves?

[Lmbauer2017]

I’m about to toss this plant regardless, it looks like cucumbers just aren’t surviving on it anymore possibly do to the heat. But this strange yellowing has been on it for weeks if not more. Recently it looks like its gotten way worse. I’ve been feeding it a 6-12-6 water soluble in hopes it would help, but I’m wondering if that’s actually contributing to the yellowing?

I'm about to toss this plant (into the compost) regardless as it looks like cucumbers just aren’t surviving on it anymore possibly do to the heat. I'd rather it not be growing and taking up nutrients. The leaves have looked close to this for weeks, but after a week or two of dumping excess 6-12-6 water soluble it looks like the leaves have gotten worse? The lower leaves look pretty good though... so maybe not nutrient burn (but I DO think I'm burning my peppers, I kept throwing leftover fertilizer into this bed that contains a massive cantaloupe vine that I figured could always use more as it's producing tons). What the heck is going on with these leaves? Is it just the heat?

 

[Chuck]

It appears to me that the plant has sunscald AND powdery mildew. With the super hot weather we are enjoying it is very doubtful if you produce any more cucs at all. I would pull the plant now. After you pull the plants and before you transplant anything else into this soil I would drench the soil with 50/50 hydrogen peroxide and water to kill any harmful fungus. And, just for elimination purposes, look on the underside of some of the most affected leaves with a magnifying glass to see if there are any mites or thrips insects. If you don't want to drench with peroxide just remove the top inch or two of the soil, sterilize it and then incorporate it back into the planting bed. This may seem like a lot of work but I have found that by doing these preventative measures it can save you a bunch of headaches later on.

 

[Chuck]

Please show a pic of the peppers

 

[Lmbauer2017]

It appears to me that the plant has sunscald AND powdery mildew. With the super hot weather we are enjoying it is very doubtful if you produce any more cucs at all. I would pull the plant now. After you pull the plants and before you transplant anything else into this soil I would drench the soil with 50/50 hydrogen peroxide and water to kill any harmful fungus. And, just for elimination purposes, look on the underside of some of the most affected leaves with a magnifying glass to see if there are any mites or thrips insects. If you don't want to drench with peroxide just remove the top inch or two of the soil, sterilize it and then incorporate it back into the planting bed. This may seem like a lot of work but I have found that by doing these preventative measures it can save you a bunch of headaches later on.

Oooo very good idea! And I definitely have thrips around the garden periodically. Whenever I spray neem it seems to take care of them for the most part. They showed up really bad on my potato plants. Within this raised bed I’ve had an awful case of leaf spot (tomato plants) and powdery mildew on cuc/zuch (none at all on cantaloupe surprisingly). All of these issues got really bad wayyy before I knew about sprays and pre-spraying though.

How much volume would constitute a drench? The area is about 3.5’x6’. The area of the tomatoes/cucs is only about 3.5’x4’ though.

I didn’t think to grab a pic of the peppers till after I got to work. I’ll post one tonight when I get home.

 

[Chuck]

Oooo very good idea! And I definitely have thrips around the garden periodically. Whenever I spray neem it seems to take care of them for the most part. They showed up really bad on my potato plants. Within this raised bed I’ve had an awful case of leaf spot (tomato plants) and powdery mildew on cuc/zuch (none at all on cantaloupe surprisingly). All of these issues got really bad wayyy before I knew about sprays and pre-spraying though.

How much volume would constitute a drench? The area is about 3.5’x6’. The area of the tomatoes/cucs is only about 3.5’x4’ though.

I didn’t think to grab a pic of the peppers till after I got to work. I’ll post one tonight when I get home.

Many vegetable plant pathogens are spread by the wind but these same fungal and bacterial spores also land on soil and this can become a problem. Having had leaf spot I am sure this and other pathogens are in your soil as they are in all soils. This is not a concern for panic however. Soils have these pathogens and healthy plants can usually fight off the infection but I like to not give the plants a chance of infection or at least reduce the chances of infection by doing all I can to eliminate the threat to begin with. And hydrogen peroxide seems to really curtail most of the pathogens. On a 3 1/2 ' x 10" space I would gestimate 4 gallons for a good drench, so 2 gallons of peroxide. But you don't have to use peroxide to sterilize the soil. You can just shovel up the top couple of inches of soil into a metal bucket and cook it in the oven for an hour after it reaches about 180F temperature. Baking soda also kills harmful fungi. You can get a few boxes of it and spread it over the soils surface and rake it in. There are numerous ways to reduce harmful fungi in the soil and many gardeners probably think I go overboard but I am a firm believer in " An ounce of prevention is worth a pound of cure." And a healthy soil is the secret to a productive garden.

 

[Lmbauer2017]

Many vegetable plant pathogens are spread by the wind but these same fungal and bacterial spores also land on soil and this can become a problem. Having had leaf spot I am sure this and other pathogens are in your soil as they are in all soils. This is not a concern for panic however. Soils have these pathogens and healthy plants can usually fight off the infection but I like to not give the plants a chance of infection or at least reduce the chances of infection by doing all I can to eliminate the threat to begin with. And hydrogen peroxide seems to really curtail most of the pathogens. On a 3 1/2 ' x 10" space I would gestimate 4 gallons for a good drench, so 2 gallons of peroxide. But you don't have to use peroxide to sterilize the soil. You can just shovel up the top couple of inches of soil into a metal bucket and cook it in the oven for an hour after it reaches about 180F temperature. Baking soda also kills harmful fungi. You can get a few boxes of it and spread it over the soils surface and rake it in. There are numerous ways to reduce harmful fungi in the soil and many gardeners probably think I go overboard but I am a firm believer in " An ounce of prevention is worth a pound of cure." And a healthy soil is the secret to a productive garden.

I am MORE than willing to go overboard, especially after seeing every plant I grew in this bed succumb to disease or pests (this was before the heat). So I still have some pepper plants (which I don't mind pulling) and this monstrous cantaloupe vine in the bed. That hefty of a soil drench is still OK with these in it right?

 

[Chuck]

I am MORE than willing to go overboard, especially after seeing every plant I grew in this bed succumb to disease or pests (this was before the heat). So I still have some pepper plants (which I don't mind pulling) and this monstrous cantaloupe vine in the bed. That hefty of a soil drench is still OK with these in it right?

It will be interesting to see what a concentrated dose of peroxide will do to strong healthy plants although I don't believe it will do anything to them except maybe make them grow a little faster because of the extra added oxygen the peroxide will provide. But if it does we will both learn something..

 

[Lmbauer2017]

It will be interesting to see what a concentrated dose of peroxide will do to strong healthy plants although I don't believe it will do anything to them except maybe make them grow a little faster because of the extra added oxygen the peroxide will provide. But if it does we will both learn something..

Lollll well this is the perfect time to experiment. I'll keep you updated on how it goes haha

 

[Lmbauer2017]

Please show a pic of the peppers

Here’s some pepper pics. The first two are near where I’ve been fertilizing (probably too liberally) the cantaloupe, the last is on the other side of the bed and seems to be doing OK.

 

[Chuck]

Here’s some pepper pics. The first two are near where I’ve been fertilizing (probably too liberally) the cantaloupe, the last is on the other side of the bed and seems to be doing OK.

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In the first and second picture it appears that the plant isn't getting enough micro-nutrients, probably iron as iron deficiency affects photosynthesis, and phosphorus toxicity affects the uptake of iron. I say this because in the first two pictures there are blotchy leaves, a sure sign of micro-nutrient deficiencies. That 6-12-6 is probably being used a little too often as I think you are getting a phosphorus buildup. Also it appears that the plant is leggy and not full, a sunlight issue. In the last picture it shows a nice, what a pepper plant should look like except for that slightly blotchy leaves. The blotchy leaves are easily addressed by the use of Liquid Iron or Chelated Iron. I recommend that you slow down the use and amount of the 6-12-6 and use a granular fertilizer which lasts a lot longer. But, all in all, things look pretty good considering our weather.

 

[Lmbauer2017]

It appears to me that the plant has sunscald AND powdery mildew. With the super hot weather we are enjoying it is very doubtful if you produce any more cucs at all. I would pull the plant now. After you pull the plants and before you transplant anything else into this soil I would drench the soil with 50/50 hydrogen peroxide and water to kill any harmful fungus. And, just for elimination purposes, look on the underside of some of the most affected leaves with a magnifying glass to see if there are any mites or thrips insects. If you don't want to drench with peroxide just remove the top inch or two of the soil, sterilize it and then incorporate it back into the planting bed. This may seem like a lot of work but I have found that by doing these preventative measures it can save you a bunch of headaches later on.

I’m about to pull this cucumber plant, and I’m trying to resist the urge to throw it in my compost bin. I’ve heard mixed reviews about composting diseased plants. I understand you should get your pile up to X degrees for Y amount of time blah blah, but I doubt that’s feasible on a small scale 32 gal trashcan. I ALSO imagine the mold is here to stay regardless, all I can do is reduce its presence. Makes me wonder if it’s more worth it to take back the nutrients rather than waste this large plant.

I had a silly idea of dunking it in a bucket of peroxide/water for half an hour, then throwing it in. I mean theoretically that would hinder it as much as a soil drench no?

 

[Meadowlark]

I’m about to pull this cucumber plant, and I’m trying to resist the urge to throw it in my compost bin. I’ve heard mixed reviews about composting diseased plants.

To each his own as they say...but I never ever put diseased discards in my compost. I can't even imagine doing that. Talk about cutting off your nose to spite your face...

 

[Chuck]

I’m about to pull this cucumber plant, and I’m trying to resist the urge to throw it in my compost bin. I’ve heard mixed reviews about composting diseased plants. I understand you should get your pile up to X degrees for Y amount of time blah blah, but I doubt that’s feasible on a small scale 32 gal trashcan. I ALSO imagine the mold is here to stay regardless, all I can do is reduce its presence. Makes me wonder if it’s more worth it to take back the nutrients rather than waste this large plant.

I had a silly idea of dunking it in a bucket of peroxide/water for half an hour, then throwing it in. I mean theoretically that would hinder it as much as a soil drench no?

Personally I never put any vining plant into my compost pile because sometimes you don't know for sure if it is infected or not. For the very small amount of compost a tomato plant, cucumber plant, squash plant or melon plant will make it just isn't worth taking a chance of infecting your entire pile. I suppose soaking in peroxide would stop it but I just don't know.

 

[Lmbauer2017]

To each his own as they say...but I never ever put diseased discards in my compost. I can't even imagine doing that. Talk about cutting off your nose to spite your face...

Personally I never put any vining plant into my compost pile because sometimes you don't know for sure if it is infected or not. For the very small amount of compost a tomato plant, cucumber plant, squash plant or melon plant will make it just isn't worth taking a chance of infecting your entire pile. I suppose soaking in peroxide would stop it but I just don't know.

LOL basically the same answer from the veteran gardeners… noted. I guess I’m being a bit overzealous about building up compost. There’s so much patience needed in this practice, I think very healthy for me in that way… when you’re not patient, it bites you pretty hard. And you don’t forget.

 

[NigelJ]

50/50 hydrogen peroxide and water

What strength peroxide do you start with? Over here (UK) hydrogen peroxide available to the public is restricted is about 10% w/v (30 vol) due to use by people in homemade explosives. At work I can get 30% w/v (100 vol) if I sign an end user declaration and that needs to be treated with care.