Cucumbers

Guy123 · Fri Jul 31, 2015 5:06 pm

I have mildew on my cucumber plant.I tried using baking soda and water doesn't seem to do anything. I put a small spoon of baking soda In a gallon of water mixed it together and used a small spray bottle. Seems to burn the leaves to even when I put the plant in shade. Help please what am I doing wrong

imafan26 · Sat Aug 01, 2015 3:30 am

baking soda does not work on mildew. If you have powdery mildew, the top of the leaf will be white if you have downy mildew it will be on the bottom and the top of the leaf will have yellow spots.

if the infection is mild and early, you can use copper sulfate. Spray when in the coolest part of the day. If the leaf has a lot of mildew, it is hard to control. If a lot of leaves have mildew, I would bag and trash the plant to keep the spores from spreading.

Milk spray and copper sulfate can be used as a preventative. It is hard to control mildew once it takes hold.

imafan26 · Sat Aug 01, 2015 3:40 am

The cucumbers at work look really bad.

The vines have very small leaves and the leaves are drying. There are many small stemmed side branches and the fruit is small and the end is curved like a "J". I pulled some of the plants out and there were no nematodes but the roots were small for their size and while there were some aphids on the leaves, the leaves looked different. The leaves all had a yellow margin and the edges were dry and crispy and the tops of the vines have very small leaves that are brown and the terminal end is toast.

I looked up what would cause this. It isn't the aphids. The aphid damaged leaves are wilted and have sooty mold and are totally infested with aphids.

What I found out was a surprise. Apparently cucumber and squash are sensitive to fertilizer. Too much burns the roots, especially in pots. My boss was telling my co worker to give them more fertilizer. It seems the excess fertilizer burned the roots. The root mass was very small so it could not sustain the growth of the vines and that is why the leaves were small and shrivelling.

applestar · Sat Aug 01, 2015 5:13 am

That's interesting! I think I have seen other members posting and asking about their cucurbits with leaves like you described.

Guy123 · Sat Aug 01, 2015 2:05 pm

imafan26 wrote:baking soda does not work on mildew. If you have powdery mildew, the top of the leaf will be white if you have downy mildew it will be on the bottom and the top of the leaf will have yellow spots.

if the infection is mild and early, you can use copper sulfate. Spray when in the coolest part of the day. If the leaf has a lot of mildew, it is hard to control. If a lot of leaves have mildew, I would bag and trash the plant to keep the spores from spreading.

Milk spray and copper sulfate can be used as a preventative. It is hard to control mildew once it takes hold.

Does this look salvageable or throw it away

imafan26 · Sat Aug 01, 2015 7:51 pm

I've seen worse. You can try the copper sulfate. you need good coverage and follow the application interval. If you can remove the most damaged leaves without adversely affecting the plant it helps. Avoid overhead watering and to prevent the spread, spray all of the leaves not just the ones that are afected.

Make sure you have not used an oil within the last two weeks.

If you have used an oil then you can try the alternative which would be 1 tablespoon baking soda and 2.5 tablespoons horticultural oil in a gallon of water. You cannot use an oil if the temperature is likely to exceed 80 degrees. It may burn the plant. Plants will definitely burn if oil and sulfur are used within two weeks of each other. Spray early in the morning while it is still cool. It works better as prevention than as cure.

Guy123 · Sun Aug 02, 2015 12:27 pm

imafan26 wrote:I've seen worse. You can try the copper sulfate. you need good coverage and follow the application interval. If you can remove the most damaged leaves without adversely affecting the plant it helps. Avoid overhead watering and to prevent the spread, spray all of the leaves not just the ones that are afected.

Make sure you have not used an oil within the last two weeks.

If you have used an oil then you can try the alternative which would be 1 tablespoon baking soda and 2.5 tablespoons horticultural oil in a gallon of water. You cannot use an oil if the temperature is likely to exceed 80 degrees. It may burn the plant. Plants will definitely burn if oil and sulfur are used within two weeks of each other. Spray early in the morning while it is still cool. It works better as prevention than as cure.

I didn't use oil with the baking soda.I just sprayed baking soda with water. Is that why didn't work

imafan26 · Sun Aug 02, 2015 2:31 pm

Baking soda needs a sticker spreader. There actually is such a thing as sticker spreader that you can usually get from an agricultural suplier. The come in ionic and non-ionic types. However, insecticidal soap or oil can be used as a sticker as well and it is a lot cheaper. Baking soda is a dessicant and helps dry the leaves. I find it works better for prevention than for cure. Even copper sulfate can only control mild problems if you get to them quickly, and works much better as a preventive.

Guy123 · Tue Aug 04, 2015 3:39 pm

imafan26 wrote:Baking soda needs a sticker spreader. There actually is such a thing as sticker spreader that you can usually get from an agricultural suplier. The come in ionic and non-ionic types. However, insecticidal soap or oil can be used as a sticker as well and it is a lot cheaper. Baking soda is a dessicant and helps dry the leaves. I find it works better for prevention than for cure. Even copper sulfate can only control mild problems if you get to them quickly, and works much better as a preventive.

Which do you think would work better the baking soda and oil or the copper sulfate

jal_ut · Tue Aug 04, 2015 4:50 pm

First off: I can't imagine growing a cucumber in a pot. When in the ground, cucumber roots go out sideways as far as the vine is long, and they may go to 4 or 5 feet deep. If you have a plot of ground, I suggest planting a few new seeds directly in the ground.

Adam26 · Wed Aug 05, 2015 7:15 am

I'm trying to get seeds for a specific cucumber in the UK can any one help it's the kirby cucumber

Meatburner · Wed Aug 05, 2015 9:00 am

Adam26, search the wide variety of seed suppliers.

imafan26 · Wed Aug 05, 2015 11:49 am

Copper sulfate has a better chance of controlling mildew than an oil, however, once mildew is established it is difficult to control no matter what you use. That is why it is better to spray preventively when conditions are ripe for mildew to develop.

digitS' · Wed Aug 05, 2015 12:39 pm

Adam26 wrote:I'm trying to get seeds for a specific cucumber in the UK can any one help it's the kirby cucumber

Someone should correct me if I'm wrong but I believe that the kirby is just what we often call a pickling cucumber.

There is confusion in the naming of cucumbers and that includes the use of the word gherkin. That should really be used for a separate species, although related.

So, a kirby is a class of cucumbers. Renee's Garden uses the term: link. If they are using the term gherkin in the UK and it is not really a gherkin, it might be a kirby.

As I say, correct me if I'm wrong.

Steve

lexusnexus · Thu Aug 06, 2015 2:26 pm

imafan26 wrote:Copper sulfate has a better chance of controlling mildew than an oil, however, once mildew is established it is difficult to control no matter what you use. That is why it is better to spray preventively when conditions are ripe for mildew to develop.

+1 and can found as this: https://www.keystonepestsolutions.com/in ... HwodZbYJwA

There are many sources for it. Not an endorsement but we use it our Demo garden.