Flushing mid veg/flower with RO

[infam0usgro]

Hello all,

So overtime I always flushed weekly to bring down my EC/PPM with RO. I learned that in coco you shouldnt flush with RO due to ion exchange. Does the same apply with soil?

Would a flush at 20 percent feed be better off instead of using Reverse Osmosis? Any insight is gladly appreciated!

 

[Kot]

Instead of having to flush to bring down you EC why don't you just feed with lower EC? The plants tell you how much food they want by measuring the in and out water. If the out water is more than 200 PPM than the water in then you need to lower your EC.

Flushing with plain water or worst with RO water is super stressing for the root zone. Even if you must flush over fed plant you should never do it with plain water. You have to start slow lowering the EC of the water so not to stress the root zone by drastically changing the osmotic pressure.

I am growing in coco and never flush. I just feed with EC that the plants need.

 

[Ikkt]

As Kot said it's stress from a sudden change in osmotic pressure and not very beneficial for the plant...

Products for leaching are usually just some sugars to get an equivalent osmotic pressure so you can leach your substrate with a nutrient free solution. Plants don't take up substantial amounts of carbohydrates, it's really just for the osmotic balance.
If you search for it you should be able to find what sugars to use and how you can approximate your nutrient solutions osmotic value. Shouldn't be that hard to figure out I guess.

But I'd recommend what Kot said, just lower your EC and/or increase runoff.
With drain to waste systems leaching shouldn't be necessary and if you do it right leaching/"flushing" is just plain detrimental.


As an anecdote:
I had cacti in extremely hot, salty substrate without knowing.
The runoff, mixed 1:2 with ro, was still above EC 3, so they were in a substrate with an EC well over 10!
But they did just fine, growing slowly and looking good. That is until I leached the substrate with tap water at EC 0.6.
A week later most got weird swelling and then startet roting!
No chance to save them.
It was the osmotic stress forcing them to take in extreme amounts of water I guess.
The point is, even extreme EC values don't have to be problematic, but sudden and rather big changes will be!

 

[infam0usgro]

Instead of having to flush to bring down you EC why don't you just feed with lower EC? The plants tell you how much food they want by measuring the in and out water. If the out water is more than 200 PPM than the water in then you need to lower your EC.

Flushing with plain water or worst with RO water is super stressing for the root zone. Even if you must flush over fed plant you should never do it with plain water. You have to start slow lowering the EC of the water so not to stress the root zone by drastically changing the osmotic pressure.

I am growing in coco and never flush. I just feed with EC that the plants need.

You're absolutely right. I guess my biggest problem is I feed my smaller plants maybe 250ml- 1 liter of water in a 3 gallon pot depending on size. As they grow bigger they get more water. I dont like drenching them and then not having to feed them for 7 days. I guess fresh oxygen to the roots every 2-3 days in soil is better in my opinion. Thanks for the insight however!

 

[infam0usgro]

As Kot said it's stress from a sudden change in osmotic pressure and not very beneficial for the plant...

Products for leaching are usually just some sugars to get an equivalent osmotic pressure so you can leach your substrate with a nutrient free solution. Plants don't take up substantial amounts of carbohydrates, it's really just for the osmotic balance.
If you search for it you should be able to find what sugars to use and how you can approximate your nutrient solutions osmotic value. Shouldn't be that hard to figure out I guess.

But I'd recommend what Kot said, just lower your EC and/or increase runoff.
With drain to waste systems leaching shouldn't be necessary and if you do it right leaching/"flushing" is just plain detrimental.


As an anecdote:
I had cacti in extremely hot, salty substrate without knowing.
The runoff, mixed 1:2 with ro, was still above EC 3, so they were in a substrate with an EC well over 10!
But they did just fine, growing slowly and looking good. That is until I leached the substrate with tap water at EC 0.6.
A week later most got weird swelling and then startet roting!
No chance to save them.
It was the osmotic stress forcing them to take in extreme amounts of water I guess.
The point is, even extreme EC values don't have to be problematic, but sudden and rather big changes will be!

Yeah didnt really realize that RO water was that detrimental to the plants. I figured by it having "0 ec" it would lower the ec which in return would help bring the levels back to normal. I will not be flushing with RO anymore until last week of flower.