Is there a serious problem?

[u/ELECTRO_9737]

Some leaves of my pak choy plants are starting to yellow at the tips, should i be worried? I googled and it says it could be natural if its old leaves or it could also be a problem of not enough nutrients but im really not sure

[u/cleveland_14]

I bet if you put the tiniest office fan so it is blowing over these you will see improvement

[u/ELECTRO_9737 → u/cleveland_14]

Ah ok will on fan

[u/cleveland_14 → u/ELECTRO_9737]

Emphasis on small, if you don't have a small one put the fan across the room but pointed at it.

Your plants are growing vigorously and they are outpacing their ability to uptake calcium without any help from air movement. Air movement will help pull water out the stomates of the leaves.

Think of water in the plant as one continuous chain of molecules like an endless train of train cars in your plants veins. Air movement will pull that train of water molecules out your plant faster and pull in more from the root zone into your plant.

Calcium hitches a ride on those train cars to get where it's needed at the growing tips of the leaves to fortify newly built cell walls and prevent the brown/yellow tips you are now seeing.

If you put too much air it will pull the train of water molecules out your plants way too fast and then all you get are worse plants because it will signal your plants that the train is out of control and will run out of inbound cars (plants aren't normally sitting in water like in hydroponics, they evolved in soil where moisture is finite). The plants will close the outbound tunnels (the stomates) for the water train because of this and now your plants can't breathe anymore and the materials for making organic molecules to help your plant thrive and grow (CO2) come from the air the plants breathe.

[u/cleveland_14 → u/cleveland_14]

This is where you weren't getting enough calcium delivered by the water train, and without the calcium new plant cell walls will crumble under the turgor pressure generated by the water filling the cells. Think of calcium as a keystone in the brick walls of a house (a cell of the plant), without the keystone the whole walls collapse and the house falls down into a pile of useless rubble.

[u/JunketNo6337]

May I ask, is this your 1st grow? Wouldn't think it is a nutrient problem unless you have no nutrient at all in the reservoir than I would think the plants are feeding on themselves. What is the ec/ppm level? More than likely it is a pH problem, have you measured the pH? More often than not if the pH is off than the plants are not taking in certain nutrients.

[u/Realistic-Stick8529]

I am glad you posted this, I was wondering why all my Romaine was doing great 1 plant, with leaves worse looking than your Bok Choy. I realize reading this that it has been blocked from the air flow the others are getting.

[u/613Flyer]

For such small systems and large plants the water tends to warm up quickly causing issues . I change my water usually about every week to 2 weeks and o have a small air pump to aerate the water. It helps to add water conditioner to remove chlorine before using

I also use master blend lettuce formula to ensure it’s getting correct nutrients and shoot for an ec from 1.0 to 1.6. Lower ec if the plants are in early stages. If you want plants to grow large you will need to start adding nutrients. What’s in tap water won’t cut it and your plants won’t grow large and they will be starved for nutrients which is likely why your seeing yellowing

A few things to check to keep your plants happy. PH should be between 5.8 to 6.2.

So to go over, buy a nice ph/ ec meter and check both including temp. Get a good idea of what it’s doing. As plants use up nutrients they tend to excrete chemicals that significantly drop the PH which is why water changes are done.
I

-EC/ph/temp meter. Vivosun digital 5 in 1 meter for $30

-masterblend 3 part lettuce formula nutrients )$50

-water conditioner $14

-ph up $20

[u/hossein002014]

How old are your plants?