Backyard Aquaponics
A place to discuss aquaponics

I have had a small setup running for a couple of months now, with varying success, my tomatoes got off to a good start and then got destroyed by blight (I think it's called). The leaves started to yellow at first - I assumed lack of nitrate and then before I knew it all the plants started dieing (leaves turning black in some instances), this happened in such short time that I had no way of saving them. I also have something or the other eating my Chinese cabbage, I inspect the leaves on a regular basis and can never find anything. Is there a safe spray, or home remedy that I can use to prevent all of this?

Welcome Axle.... FYI, member "Synaptoman" is a fellow countryman ...

Tomatoes, I'm not completely sure about when you say the leaves turned "black".... can you describe it further... sounds possibly silimlar to a mosaic virus like you see in tobbaco....

Your Chinese Cabbage.... I'd put my money on white butterflies/green caterpillars..... We use a powder called "Dipel" or BT powder.... made by a company called "Yates"... not sure if it's available in SA?

There's been suggestions that a rhubarb spray can be effective...

The leaves of the tomatoes started with a yellow tinge turned to brown and then actually turned black predominantly on the outside of the leaves, I had basil in the same bed which suffered a similar fate (turning black immediately)but did not kill the actual plants. I did have my 'spray bars' to distribute the water above the gravel bed, which I have now laid flat on top of the gravel as I thought it may have been some kind of fungal growth due to excessive moisture. I have never grown veggies before thus I have no previous knowledge as to what to look for. Another point of interest is that I am now growing a type of runner bean and they are showing brown spots on the leaves, without any seemingly ill effect???

If the spray bars were up above the bed and "splashing" the plants... and there was a rapid cold snap...

It's possible that what occurred might be what's known as a "black frost"...

It effectively burns the plant leaves... and yep it's fatal.

Brown spots on bean (or other plant) leaves are usually a sign of a deficiency, but usually not fatal.

this sounds a lot like a potassium issue. I had similar issues until I added some potash to my system. I also added Iron chelates. so could be a combination of the two.

Many thanks, I have just planted a new crop, various different cold weather crops as we are moving into winter, will keep you posted. Will also be adding a couple of new fish to the system as I have had feeling that there was a lack of nutrient. Thanks for the help.

Hi Axle, welcome to the forum

You should try to catch up with Synaptoman, he had a few disease problems too if i remind well and has used BT previously. His thread here is called a south African system. He is very good at aquaponics as he is starting a lot of systems, plus his and a hatchery. He could be a lot of help.

I've had blight like yours, did the leaves become yellow and dry like crips and then crinckled and black, most of the tomatoes plants of the southern part of france died of that last summer (rained often and weather was cold), mine were not brilliant but didn't die because they were close to the sea and had salted wind blowing on them.
Some people here were talking of using milk on the plants.

You could start a personnal system thread with pics so that we get a more precise idea of how your system works and could maybe help you more.

Good luck in the fantastic world of aquaponics

Thank you for the response, my tomato plants did exactly as you said, I was not a happy person as they had just started supplying me with great tasting tomatos, they were a little undersized to start and then as the plants matured bigger fruit started to appear and then bang they all died. Thank you all for the heads up on Synaptoman I am already in contact with him and he has had similar problems to me - his system is inspiring