Plants suddenly getting brown and yellow leaf

[OleReynard]

Calcium and manganese had the problem myself, exact same thing.

 

[Thighland]

Here's some more pics, the problem didn't get any worse. I didn't water for 5 days, then waited another 5 days before watering again. I think they've been slightly over watered for a long time and only recently it became an obvious problem.

Plants that were planted higher showed less problems and less insect damage.

 

[Thighland]

This problem hasn't been fully resolved. This is my second year growing in the tropics, plants are healthy until they flower, then they go downhill.

Last year I thought it was too many inputs, so this year I kept it to a min. Recently I watered with magnesium sulphate, which may have helped a little, difficult to say.

The water comes from fish tanks, so should have plenty of N, but I doubt it is getting too much. Any help much appreciated.

The plants above are just starting to flower and starting to yellow.

 

[TanzanianMagic]

This problem hasn't been fully resolved. This is my second year growing in the tropics, plants are healthy until they flower, then they go downhill.

Last year I thought it was too many inputs, so this year I kept it to a min. Recently I watered with magnesium sulphate, which may have helped a little, difficult to say.

The water comes from fish tanks, so should have plenty of N, but I doubt it is getting too much. Any help much appreciated.

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The plants above are just starting to flower and starting to yellow.

"The plants above are just starting to flower and starting to yellow."

Early to mid/late flowering is when they need extra nitrogen.

Nitrogen is the growth nutrient, and they are growing their flowers.

 

[OleReynard]

This problem hasn't been fully resolved. This is my second year growing in the tropics, plants are healthy until they flower, then they go downhill.

Last year I thought it was too many inputs, so this year I kept it to a min. Recently I watered with magnesium sulphate, which may have helped a little, difficult to say.

The water comes from fish tanks, so should have plenty of N, but I doubt it is getting too much. Any help much appreciated.

View attachment 18971188 View attachment 18971187 View attachment 18971186 View attachment 18971184
The plants above are just starting to flower and starting to yellow.

Fish tank water has alot of ammonia

 

[TanzanianMagic]

"The water comes from fish tanks, so should have plenty of N, but I doubt it is getting too much. Any help much appreciated."

That's not enough nitrogen for early - mid flowering. Bloodmeal, high nitrogen bat guano, or just a few helpings of relatively high nitrogen vegging food.

The combination of early flowering, and chlorosis of the leaves means too little nitrogen. Sometimes it's underwatering too.

 

[Thighland]

Thanks to everyone for their help. I think it's been a variety of factors, including lack of N, overwatering, mites and heat stress. I thought the fish water and few amendments were enough, but most likely not. I added bone meal about 2 months ago, possibly too late for the early flowerers.

The photos show the late flowering are doing well, with the others really suffering. I think there may be nematodes or some other issue, pls check the last photo.

In the photo below you can see white powdery balls that appear close to the trunk. Any idea what they are?

 

[TanzanianMagic]

You should absolutely get rid of the cardboard. It is a food source for bacteria and fungi.

 

[Thighland]

You should absolutely get rid of the cardboard. It is a food source for bacteria and fungi.

That's interesting. The idea is to keep the sun off the soil. It's 35c everyday. The cardboard pretty much stays dry, I move it when I water. It's a similar idea to mulch, which isn't used in a lot of tropical countries and it may have to do with spreading mold and disease.

 

[TanzanianMagic]

That's interesting. The idea is to keep the sun off the soil. It's 35c everyday. The cardboard pretty much stays dry, I move it when I water. It's a similar idea to mulch, which isn't used in a lot of tropical countries and it may have to do with spreading mold and disease.

The problem is condensation. Anything that can decompose pretty quickly is a no-no around plants. Basically you can use cardboard to grow mushrooms.

If you're looking for mulch, hemp bedding is great. It can be bought at pet stores. It also has all the compatible mycorrhizal fungi in it. And it can possibly be a substitute for perlite.

Also, there are signs of insect activity, although not yet to the extent of it stopping the plants' growth. The remedy is to spray them with water and a very light solution of compost tea, or a fermentation of hempsprout seedlings if you have them, to prevent nutrient leaching.

A strong spray, 10 seconds per node, top-down, inside the plant then outside, should knock more than a few of them off the plant. Every day for 3 days, once a week after that, then once every 2 weeks.

 

[Thighland]

The cardboard stays completely dry, it won't be decomposing, underneath are rice husks. I will add more, but they are not available now. Hemp bedding isn't sold in my country. I think the plants are being attacked because they're weak. There is something burrowing into the stem on one plant, other plants have had nematodes. This is a new property, there issues with the soil.