crinkling leaves

[Luckypup]

Does anyone know what is going on here? It is affecting about 1/4 of my grow. They are outside but started in a GH with fiber pots and had a couple of excessive heat days >120F a month ago. It affects only parts of the plants and about half of the tips. The white powder is from a dusting..

 

[Creeperpark]

When it gets hot plants can't use as much fertilizer as they do when it's cool. The main reason is that plants use a lot of extra water to keep cool by means of water transpiration. When moving a lot of water if you add fertilizer the fertilizer will add up to be too much. Wait to use fertilizer only when it's cool and the plant transpires normally.

 

[Creeperpark]

Check your plant's containers during the heat of the day and make sure they are not getting too hot in the full Sun. If they are getting too hot, put something in front of the pots to shade them. I use greenhouse shade clothe's as well as cotton sheets. Even hay will help to keep the pot cooler because excess heat will kill your plants.

 

[Creeperpark]

Here's a note from General Hydroponics feeding chart.
Arid bright hot environments cause plants to drink more than if grown where its humid dim and cool. Thus gardeners should use less concentrated nutrient solutions when growing conditions are more intense in order to lessen the risk of overfeeding.
When it is hot don't use fertilizers!
Happy Gardening Friend.

 

[Luckypup]

Here's a note from General Hydroponics feeding chart.
Arid bright hot environments cause plants to drink more than if grown where its humid dim and cool. Thus gardeners should use less concentrated nutrient solutions when growing conditions are more intense in order to lessen the risk of overfeeding.
When it is hot don't use fertilizers!
Happy Gardening Friend.

Thanks. I'll check the pots for heat tomorrow.