Cucumbers Ain’t Doing Well

[Shean Smith]

Sorry for the incorrect English, but incorrect cukes are deserving of incorrect English. My bush cukes are developing ugliness on it’s leaves. I’m including some pictures of my cucumber challenge. With my hat in my hand I’m requesting someone with greater knowledge than me to shed some light on this blight (it had to rhyme). I have baking soda and API  “Leaf Zone” to mix up. I’ve already tried MaxiCrop; it’s been a day since I applied it. I also reapplied it this morning (4/26/12). Help anyone?

[Japan Aquaponics - アクアポニックス 日本]

Hey Shean,

Sorry to hear about the cucumbers.  There could be several reasons for this happening I think... I am no expert on cucumbers though so hopefully someone else will also chime in.  Is your system relatively new by any chance?  It could be that is your system is relatively new that there are insufficient nutrients in your system to grow something like cucumbers.  Also, what is your Ph like in your system?  It could potentially be nutrient lock-out if your Ph is not quite right.  Just a couple of potential things to consider... sorry for not a more comprehensive or definitive answer.

[Shean Smith]

Thanks for the reply. I realize there are many variables with a new system; yes my system is relatively new. I keep constant watch on the PH and it is within normal limits (about 6.4). Everything else is growing well. I supplement with MaxiCrop and iron chelate a couple of times each week (a little at a time). I recently got some potassium to add to the system. If they die off, I’ll put some more cucumbers in, but I’d rather get this problem solved first.

Japan Aquaponics - アクアポニックス 日本 said:

Hey Shean,

Sorry to hear about the cucumbers.  There could be several reasons for this happening I think... I am no expert on cucumbers though so hopefully someone else will also chime in.  Is your system relatively new by any chance?  It could be that is your system is relatively new that there are insufficient nutrients in your system to grow something like cucumbers.  Also, what is your Ph like in your system?  It could potentially be nutrient lock-out if your Ph is not quite right.  Just a couple of potential things to consider... sorry for not a more comprehensive or definitive answer.

[Gary P]

Hi Shean,

I like you am having the same problem with my system.  My cukes and spinch are both doing poorly. The rest of the plants seem to be doing great. I did notice the broccoli had yellow new leaves on them, but within a few days they turned green, and look fine now. Are you growing inside or outdoors?  I am in a greenhouse with a 40% sunshade on it.

I will try to post a picture in a day or so. I have added more cucumbers to the same grow bed and as of today they seem to be doing ok.

Gary

[Patti Taylor]

Could this be bug damage? I had thrips do something similar to my lettuce.

[Rob Wulf]

Hey Shean,

I'm not an expert on aquaponics (I'm a beginner in this adventure), but I do know alot about gardening. I used to work in a nursery way back when in the day and we would have customers that would bring in their plants to have us "identify" what the problems were. If I was to take a shot in the dark, it's either a nutrient deficiency (cucumbers are heavy feeders) or those leaves were sprayed with something sitting in the hot sun and got burnt. I doubt they got burnt so it's probably that they arent getting enough to feed off of. Few questions...how long has your system been going? Is this happening to the whole cucumber bush or is it starting from the bottom up? Are you getting new growth and is it happening to the new growth also? At what percentage of the bush looks like the leaves above? Here's a website I found that might help a little...

http://agropedia.iitk.ac.in/?q=content/deficiency-symptoms-nutrient...

 

The downside is that in an aquaponics type of system, we have to rely on the fish to then rely on the bacteria to do what its supposed to do. How old is your system?

[Shean Smith]

I’m growing outdoors in a greenhouse. I’m in the process of replacing my plastic sheeting from our recent wing storm here at the Alabama Gulf Coast. My temporary covering is some construction grade 6 mil plastic sheeting that’s supposed to be clear (opaque in reality). All of my other plants are doing great. I’ve had a few bugs enjoying my cabbage and broccoli, but marigolds have seemed to chase them away.

Gary P said:

Hi Shean,

I like you am having the same problem with my system.  My cukes and spinch are both doing poorly. The rest of the plants seem to be doing great. I did notice the broccoli had yellow new leaves on them, but within a few days they turned green, and look fine now. Are you growing inside or outdoors?  I am in a greenhouse with a 40% sunshade on it.

I will try to post a picture in a day or so. I have added more cucumbers to the same grow bed and as of today they seem to be doing ok.

Gary

[Shean Smith]

Experience is experience; of that I’m sure so your input is greatly appreciated. My system is about a month old. I’ve made a few rookie mistakes with the fish without any fatalities. Because of my error and a sudden last gasp of life from Mr. Freeze, my fish haven’t been eating and not producing much ammonia. I’ve had to get the water temp up. I’ve supplemented with MaxiCrop and iron, but haven’t given them any potassium until now. This problem is starting from the bottom up. The top leaves aren’t affected and the blooms are beginning to show some stress. It does appear as if there’s new growth at the top, but the top looks pretty good. The big leaves seem mostly affected; I’d say about a third of the bushes are poor-looking. Thank you for the assistance

Rob Wulf said:

Hey Shean,

I'm not an expert on aquaponics (I'm a beginner in this adventure), but I do know alot about gardening. I used to work in a nursery way back when in the day and we would have customers that would bring in their plants to have us "identify" what the problems were. If I was to take a shot in the dark, it's either a nutrient deficiency (cucumbers are heavy feeders) or those leaves were sprayed with something sitting in the hot sun and got burnt. I doubt they got burnt so it's probably that they arent getting enough to feed off of. Few questions...how long has your system been going? Is this happening to the whole cucumber bush or is it starting from the bottom up? Are you getting new growth and is it happening to the new growth also? At what percentage of the bush looks like the leaves above? Here's a website I found that might help a little...

http://agropedia.iitk.ac.in/?q=content/deficiency-symptoms-nutrient...

 

The downside is that in an aquaponics type of system, we have to rely on the fish to then rely on the bacteria to do what its supposed to do. How old is your system?

[Rob Torcellini]

check the underside of the leaves for aphid damage.

[Japan Aquaponics - アクアポニックス 日本]

Hi Shean,

Based on what you have said, I would have to go with nutrient deficiency in your system.  It is just too young to be supporting cucumbers very well - as Rob said, cucumbers are heavy feeders.  You may want to consider removing the cucumber and put more less nutrient-hungry plants in initially.  It takes a while for the bacteria and the nutrient level to really build up properly, and so I think that to give yourself the best chance of developing a stable system then you may want to put less heavy-feeding plants in.

You said that your Ph is at 6.4 which is a little low, but not terribly so.  If you can bring that up closer to the 7 mark then your plants will then also be able to access the nutrient more easily and will also be good for the bacteria.  You probably don't need to be adding iron twice a week - that may be a little too much?

[Matt Rosso]

At first glance at the begining of the leaf damage it looked like a leaf mite problem. It could be a K def as suggested.  You said that you've just treated them yesterday.  I think you need to be patient and see if what you did will make a difference.  Of course you need to be looking at leaves that have not been infected yet.  the damaged leaves will not be repaired, you'll only be able to keep the new leaves from having this problem.  Lets give your last treatment a couple of days to at least a week.  Are your new leaves having this problem?  mites usually attack older leaves so keep an eye on your system.  Of coures if it is nutrient def, give your system some time to mature.

[Larry]

I have read that the iron should be a Tsp about once a month or so,  not a few times a week. also your PH is just a  touch low target 6.8 one up or down ok but tartget 6.8. With your Ph below 6.8 you can still get a chemical lock out of some nutriants.

[Shean Smith]

Hi Matt,

Thanks for you reply. The new leaves aren’t affected.

I’m leaving well enough alone. 

Matt Rosso said:

At first glance at the begining of the leaf damage it looked like a leaf mite problem. It could be a K def as suggested.  You said that you've just treated them yesterday.  I think you need to be patient and see if what you did will make a difference.  Of course you need to be looking at leaves that have not been infected yet.  the damaged leaves will not be repaired, you'll only be able to keep the new leaves from having this problem.  Lets give your last treatment a couple of days to at least a week.  Are your new leaves having this problem?  mites usually attack older leaves so keep an eye on your system.  Of coures if it is nutrient def, give your system some time to mature.