Hydroponic garden - tomatoes and cucumber issues

[mb4006]

Hello all, I am fairly new to hydroponic gardening and recently built a system from scratch on my balcony housing 36 plants. I am using General Hydroponic 3-part nutrient solutions. About 2 weeks in, everything is growing fine but noticed white lines on the tomato leaves and what appears like burns on the cucumber leaves - see photos below. I tried to do some research and came up leaf miners although did not find any. Could this be a mineral deficiency?

Thank you for your help.
Mike

[applestar]

Those squiggly lines are definitely leafminers — they could be moth caterpillars or fly maggots, and if moth caterpillars, would eventually build pupa between the leaves and can be located. Maggots are less easy to observe and are usually discovered by dark green/black pocket end to those tunnels.

Since they are protected by the top/bottom leaf membranes, they are nearly impossible to spray/kill — easiest to cut out squiggles parts of leaves with scissors or remove mangled leaves completely. Dedicated and persistent removal makes it easier to spot new infestation.

When planted in potting mix/containers, one way to break their life cycles is to mulch the soil surface with plastic to keep them from dropping down and burrowing to pupate — not sure if hydro would be enough to prevent local next generation.

I do see one cucumber leaf with squiggles — that would definitely be a fly maggot type.

Other leaves could be simply physical damage from those leaves beaten up by winds against the balcony railing posts, or could be sign of downy mildew starting. Are you spraying them preventatively?

[applestar]

Tomatoes don’t need insect pollination, and cucumbers wouldn’t either if they are parthenocarpic, so one strategy to consider for the future is to enclose them all in a growing area that is covered/protected with insect mesh/screen.

[imafan26]

The patchy areas on the cucumber does look like sucking pests. Most likely mites. Thrips also cause patchy spots and stippling. The pests will be on the undersides of the leaves, but mites are especially hard to see without magnification.

I don't know if it is the lighting, but the leaves are all dark green. How much light are the plants getting?

[mb4006]

Great information, thank you! I will start cutting out/ removing the leaves and hopefully will solve the problem. I have not been spraying at all but just ordered a spray off Amazon so will start tomorrow.
Thanks again for your help!

Those squiggly lines are definitely leafminers — they could be moth caterpillars or fly maggots, and if moth caterpillars, would eventually build pupa between the leaves and can be located. Maggots are less easy to observe and are usually discovered by dark green/black pocket end to those tunnels.

Since they are protected by the top/bottom leaf membranes, they are nearly impossible to spray/kill — easiest to cut out squiggles parts of leaves with scissors or remove mangled leaves completely. Dedicated and persistent removal makes it easier to spot new infestation.

When planted in potting mix/containers, one way to break their life cycles is to mulch the soil surface with plastic to keep them from dropping down and burrowing to pupate — not sure if hydro would be enough to prevent local next generation.

I do see one cucumber leaf with squiggles — that would definitely be a fly maggot type.

Other leaves could be simply physical damage from those leaves beaten up by winds against the balcony railing posts, or could be sign of downy mildew starting. Are you spraying them preventatively?

[mb4006]

This section of the balcony is facing east so they get more or less half a day of direct sunlight.

The patchy areas on the cucumber does look like sucking pests. Most likely mites. Thrips also cause patchy spots and stippling. The pests will be on the undersides of the leaves, but mites are especially hard to see without magnification.

I don't know if it is the lighting, but the leaves are all dark green. How much light are the plants getting?

[imafan26]

Most flowering and fruiting plants need 6-8 hours of good sun. Leaf crops can do with a little less. It explains the darker leaves and maybe the long internodes on the tomatoes. If the tomatoes are indeterminate they do have longer internodes, but usually not that long.

[applestar]

what kind of “ spray” did you get?

I usually only use non-toxic preventative fungal sprays that can be easily mixed or diluted at home (various recipes made with milk, vinegar, yogurt whey, potassium bicarbonate, sodium bicarbonate, neem oil, canola oil, soapy water, etc.)

[mb4006]

That's a good point. I guess I might have to use the system for leafy greens and herbs only at the end if neither cucumbers or tomatoes produce.

Most flowering and fruiting plants need 6-8 hours of good sun. Leaf crops can do with a little less. It explains the darker leaves and maybe the long internodes on the tomatoes. If the tomatoes are indeterminate they do have longer internodes, but usually not that long.

[mb4006]

I ordered Natria Neem Oil Spray https://www.amazon.com/gp/product/B00FY4YXHS/



Any experience with it?

what kind of “ spray” did you get?

I usually only use non-toxic preventative fungal sprays that can be easily mixed or diluted at home (various recipes made with milk, vinegar, yogurt whey, potassium bicarbonate, sodium bicarbonate, neem oil, canola oil, soapy water, etc.)

[imafan26]

I don't see a lot of fungal disease. There are some angular patches on the cucumber that could be angular leaf spot. But there isn't much. Most of the fine white dots are likely to be from thrips. Both thrips and mites cause stippling, drying of the leaf and flower edges and leaf curling or distortion. You have to look at the undersides of the leaves to find them.

https://www.omafra.gov.on.ca/english/crops/facts/14-001.htm
https://ag.umass.edu/vegetable/fact-she ... leaf-spots

A lot of people like to use neem. It smothers pests, but you need to make contact and have good coverage. It probably won't stop the leaf miners but may stop sucking pests. Neem is used as an antifungal preventive spray. Neem is not curative for fungi.

[applestar]

I have 100% cold pressed neem oil that I dilute with canola oil as carrier oil, then make up insecticidal soap with a bit of liquid soap. I use this mostly for aphid infestation when there are no Garden Patrol at work. I have seen neem advocated as good for KEEPING aphids away as well, though I don’t have definitive experience.

I spray enough for the solution to drip onto the soil underneath, which I hope helps with fungal gnats and mites in container plants. (I just bought neem “cake” seed/fruit meal for the first time to try as soil treatment and fertilizer)

My neem oil doesn’t stay in solution with the current recipe, and separates out into sprayer-clogging clumps within 1 hour, so it’s inconvenient but helps me to be frugal and make only as much as I can use up within the time limit.

Neem does have a distinct strong odor so I wouldn’t recommend for near-harvest crops and definitely not near harvest leafy greens and soft fruits.

I add a bit of potassium bicarbonate to this mix when I want to add the extra anti-fungal oomph.

ANY oil containing sprays should be used with caution in terms of concentration and temperature as well as direct sun, or you could smother or burn the leaves.