Backyard Aquaponics
A place to discuss aquaponics

Hello,

can you please advise why there's some deficiency on old leaves.

Hi Nit.

It would help if you can provide more photos, including some that show the whole lettuce in the system and an overview of the system itself.

Could be some form of leaf spot. These tend to affect older leafs first.

also what type of lettuce is this ?

what temps and humidity are you experiencing ?

_________________
.
Darren ( dlf_perth )

May the fish sh*t and the plants grow.....

That looks like thrip, a pest not a deficiency. Look closely under the leaves, take a photo and blow it up, there will be tiny black bugs.

_________________
www.havehomewilltravel.com
Life on the road

+1 - either that or possibly mites

Indeed, I have checked closely on the older leaves and there's many tiny insect..seems like thrips... how I can eliminate this ?

?

It's been awhile since the post with pictures are you having the same issue and are you actually seeing leaf damage?

See if maybe they aren't Springtails instead (they look very similar to thrips in some ways). These are very common in AP systems and are detritovores so they don't do much if any damage.

I haven't had to deal with thrips yet but seems like there are some options that might work. I've seen oil or soap based sprays (like safer soap) suggested on some university sites and they can be used if you are careful - you don't want these getting in the water at high enough amounts that they can coat the surface and kill your fish.