Yellow Leaves on Hydroponic Tomatoes

[Nuttyneddy]

Yellow leaves tomatoes is it too much water or magnesium deficiency?

[applestar]

I don’t know anything about hydro culture, but it takes A LOT to have tomato deteriorate this far just because it’s growing in water.

Something seriously off about the water including nutes I suppose is possible, but I would wonder about possible sucking pests on underside. Were the color of the leaves stippled at first? ( Can’t tell from photo)

[imafan26]

It is nutrient deficiency but has many causes, from salt being to high, pH out of range, Too much or imbalance with other nutrients like potassium and phosphorus. All of these can cause multiple micro nutrient deficiencies. It is mostly the top leaves affected so likely an immobile element. Tomatoes have different requirements at different stages. Magnesium is a mobile element. Interveinal chlorosis is a symptoms of multiple micro nutrient deficiences and the main causes of those are pH that is too high or lock up from other nutrients.
https://ohioline.osu.edu/factsheet/hyg-1437
https://blog.bluelab.com/common-nutrien ... -in-plants
https://edis.ifas.ufl.edu/publication/HS1373
https://www.growveg.com/guides/how-to-I ... iciencies/

[Nuttyneddy]

My ph 6.9 and nutrients at 580ppm. The water temp is about 30deg C. I have reduced the ppm they were over the 900 ppm. Have not tried Ebsom salts.

[imafan26]

It is not likely a magnesium problem, because if the top leaves are affected most it is an immobile element not a mobile one that is affected and chlorosis from magnesium starts on the bottom leaves first
https://blog.bluelab.com/magnesium-deficiency-in-plants

Your pH is too high and is probably preventing the nutrients from becoming readily available. Correct the pH first. Adding more nutrients won't help if they are not available to the plants.

"The pH of the water should remain between 5.0 and 7.0 at all times for optimal nutrient absorption. The pH of the nutrient solution should be between 5.5 and 6.0. The electrical conductivity of the water should be less than 0.5 mS/cm."

https://www.npktechnology.co.uk/blogs/n ... c-tomatoes

I suggest you flush your system and remix your solution.Every time you add more of this or that, you are changing the balance with the other elements in the solution and that makes it easier to start over with the correct ratio than to try to fix it. This is a case where you need to be a baker and not a cook. These two articles will help. The second one has the basic recipe for the initial solution. The first link explains that tomato nutrition is complex and requirements change at different stages of growth. Green leafy plants are not grown to flowering or fruiting stage. They don't need to change from growth to bloom fertilizer. The same thing happens when you grow in the ground. If you keep your in ground tomatoes on a high nitrogen fertilizer, it will grow vegetatively instead of concentrating on fruit and flowers. To promote fruit, the fertilizer needs also change. You would need less nitrogen but more phosphorus and potassium to promote roots and fruit. Temperature and light will also influence maturity.
https://howhydroponics.com/how-to-grow- ... ky-method/
https://www.ctahr.hawaii.edu/hawaii/dow ... matoes.pdf

[Nuttyneddy]

I have cleaned and replaced my nutrient mix. I have also got the PH down to 5.00 the ppm is around 1300 which according to one sight is ideal for tomatoes. The weather here has been very changeable. From nearly 100 deg f for a week and then a cold snap down to 50deg f. I have lost some lettuce seedlings which have suffered badly from the wind and weather.

[Nuttyneddy]

No improvement other plants dying

[Nuttyneddy]

Have problems sending picture

[imafan26]

The tomato has almost doubled in 3 days and the top leaf looks greener. So It does look like there has been some improvement. It is harder for plants in water culture to recover. It looks like the nutrients are being taken up better. It is a big deficit to make up and the plant has no reserves to draw from since there is no soil. You have to maintain and the nutrient levels in the water and check to make sure that the root system is healthy. If the roots are turning brown, then they are not going to recover. Fast growing plants don't take setbacks well. If the plants have severe deficits it would be better to replace them.

[Nuttyneddy]

I do have root rot on some plants. The weather has been very hot and believe the water and nutrients have been affected by the heat. This would mean that the plants would be suffering lack of oxygen.

[applestar]

Funny — I wasn’t going to mention it but I had a tomato cutting that turned yellow like that in a jar of water after being neglected on the windowsill for about a month during summer….


Can you aerate the solution somehow to add oxygen? I’ve encountered all kinds of simple methods while dabbling in aquaponics….

[pepperhead212]

Wouldn't the water be aerated when flowing through that column? I don't know how they work - I only grow in DW hydro, and it is always aerated, both by an airstone and a small pump, which are always running. And I only grow greens and herbs.

[Nuttyneddy]

This is a root rot victim I tried kratky method with this plant. I think hot weather has contributed to this

[pepperhead212]

I had horrible root rot on some plants early on, even with the aeration, but just an airstone. Then I started using those aquarium pumps, used for undergravel filters, but they can be attached to a sponge filter, as well, so that's what I do. And I put that Hygrozyme in the tubs, as well, which basically helps break down the dead roots. And it doesn't take much - a half liter bottle lasted me over 3 years, for about 35 gallons of water DW tubs.

Just having grown fish in aquariums since I was 10 years old, that stagnant Kratky method does not appear to me like it will work that well, even though it is done all over.

[imafan26]

When you change the solution in your tank. It is important to clean the system well. Especially if you have root rot, it means that the bacterial count in the water is high. Clean the parts of the system including the tubing with soap and water and bleach to disinfect. If you can use R.O. or filtered water to refill. Wash out your net pots and if you use media, make sure it is clean and fresh. Aeration should not be a problem with a flow by system. The bacteria that are feeding on your dead and dying roots are further contaminating the water in your system.

Kratky was developed by Dr. Bernard Kratky of the University of Hawaii. It rarely gets to 100 degrees here unless you are surrounded by concrete in August, but it does get to 88-91 in summer all the time. Our humidity keeps it from getting hotter, however, it feels like you are in a steamer. Water temperatures are usually lower than air temperature. Temperature does affect how fast bacterial grows, but in hydroponics it can affect how the nutrients the nutrients are taken up. The ideal water temperature is between 65 - 80 degrees. You can use some cooling methods like painting the tank white, shading, ice, or chillers. Higher temperatures will encourage more disease, but diseased and unhealthy plants will only spread contagion. Kratky works well in a balanced system, the important thing is to keep it clean. Once rot starts it spreads to the entire tank.

[Nuttyneddy]

That tomato plant has improved greatly really pleased

[pepperhead212]

Definitely looks a lot better - that's great!