Water Basics // 2 liters every 2 days vs. 1 liter every day

Hi everyone!

Easy question, back to the basics:

My plants could grow having 2 liters per pot every two days and 1 liter per pot every day and also 0,5 liters twice a day. What do you think is better?

Final water amount = the same.

Please do not just respond it depends. If you truly believe it depends indicate on what factors and how sensitive these are.

0.5 liters twice a day if that is the amount the leads to an ideal water-air ratio and if you give the first in the morning (when light goes on) and the second watering half way the light period (assuming 12/12).

"if that is the amount the leads to an ideal water-air ratio"
There you go I think you put light over my dilemma, thanks @Sativied !!

then next questions are:

• How do you find the ideal water-air ratio?
• Is it a sweet-spot?
• Is it a <range>?

Please lets make it easier obviating for the moment salt accumulation.
again: Please do not just respond it depends. If you truly believe it depends indicate on what factors and how sensitive these are.

IvAx said:

How do you find the ideal water-air ratio?

Click to expand...

By measuring in the same way you do with ppm levels in hydro, you look for the amount that results in the largest amount of uptake. This is exactly why I use a Blumat Tensiometer (google it... artificial clay root with a tensio meter with digital display) on soil. Not even sure they are available in the US, I've mentioned them before a couple of times in these forums, but they are quite popular here in NL.

That tensiometer is more like a learning tool, get a more precise feeling than lifting the pots (which in a scrog etc isn't always possible or desirable), but, it also shows major increases and decreases so you can adjust faster than when noticing increased uptake after the fact (pot being dryer than usual). It also provides another indication to determine harvest day. Whether you actually use a meter or lift the pot or gauge it by feeling, it's still the same deal, compare water uptake to the water you provide.

What is also confirmed is that it variates a lot throughout the pot, after watering, and when the water contents becomes low (ie. more dry near the edges for example). So that makes a sweet spot impractical because you'd never achieve it constantly and equally throughout the pot. So in practice it's always a range.