A question from a fellow grower:
I want to ask you few questions.How much liters of water do a plant need when it dried out.I read that it depends on pot’s size and plant’s age.Can u give me an information about which week and pot size need how much water because everybody say diffrent things.Other question is for example a nutrient says 40ml for 1 gallon(3.7 liters) when I feed my girl will I use all this 1 gallon mix for one plant because my pot’s size can be 5 liters or 20 liters whatever and for ex in vegative phase I will use root and grow nutrients in this case for ex. 40ml root developer and 40 ml grow nutrients will need 2 gallon and I confused about it.I now these questions are absurd but I’m really noob 
questions are why this forum is here. and we were all noobs at some point. some of us still there heh.
everyone says different things because,…there is no set rule of how much water a plant may need at different times.
that being said, there are some guidelines to go by. but, as your plant matures,…the requirements will need to be adjusted accordingly. thats why nobody will just give you a direct simple answer, truth is, it doesnt exist.
so, basically you want to water your plant when it shows signs of wilting. leaves droop slightly, she is probably a little thirsty. you can also check soil from the top. while the surface will surely be dry,…about 1-2 knuckles in should not be. if it is,…she is probably a little thirsty.
the amount you will use at this point, will vary. but you want to fill container so it saturates the soil well. pour slowly and evenly…when you notice run-off (water dripping out of bottom) youre almost there…10-20% of runoff is normal. once you see that, done.
i have learned that watering is one of the things you kind of just have to get a knack(sp) for. as you become more familiar with the growing process,…you will start to recognize signs that your plant will show you. she tells you what she needs.
good luck!
the amounts you mix with water, are explained in gallon/ml in order to help you mix the correct ratio.
so if it says 40ml per 1 gallon. that is just a guideline to use. for every 1 gallon of water,…you would add 40ml of nutrient. whether it is 1 gallon youre making, or 100. that 40ml/1gal. is your ratio.
that being said,…especially when plants are younger,…it is highly recommended to use HALF of what the manufacturer says to use. it is very easy to give young plants a nutrient solution that is too strong, and results will be undesirable. so i would start with 20ml per gallon.
i dont think you will have to pour the entire gallon of your mixed solution for 1 plant. that seems excessive.
but you can fill container until you see runoff like i explained in other post.
good luck!
Thank you for your answers and explain this simple to me.It really helps so much to me about questions in my mind.Have nice grows
its my pleasure.
but i would like to clarify 1 thing.
when i said:
i was assuming you are currently using small containers. as your plant grows and ends up in larger container, using 1 gallon or more would not be uncommon. depending on size of container.