How much water?

I just transplanted my plants to a much bigger, 16 inch planter - 16.2 gallon / 61.17 Litres. I'd post the URL only I can never seem to post URL's on this site when using my smartphone. The dimensions of the planter are : 16" width x 24" height x 16" depth. If you visit www.lowes.ca it's item#: 1477023G. My questions are : 1) How much water would you recommend I apply for a planter this size and 2) Am I the only one who can't post URL's on this site using a smartphone????

4 gallons?! Yikes....I watered it with only 1 gallon thinking that would suffice. I'll be watering them tomorrow so I'll up the amount. This is my first grow so I'm kinda learning as I go along. Thanks for the help!

You're welcome, no problemo! I've never grown in anything that big (16 gallons), but the 1/4 volume "Rule of thumb" should scale up nicely. It works pretty well for anything from a 4" pot to a 5 gallon bucket, in my experience.

It may take a little trial and error to find your "Sweet Spot", but be sure that you allow for a good amount of "Runoff" (over-watering). Whatever the total amount of water you add-in; you should get about 20-25% of that amount back as runoff (best if added slowly, a little at a time - giving it time to soak in instead of just running through in "dry channels". Getting 20-25 % runoff every watering acts like a series of "Mini-flushs", making a full-on flush totally un-neccesary (something for chemical nutrient users to keep in mind). If you're using organic nutrients, 10-15% runoff is probably ok.

I use a few drops and up to 5% runoff, if any.
You watering amount depend on your medium - coco would take about 8 liters for 60L of substrate while a mostly compost substrate could take 30 liters without a problem once dry, as long as the watering is slow.

If you did not add tuff or a similar agent you should note that getting the substrate in a 60L tub too dry can cause it to shrink significantly and it might tear roots apart.
I love big pots and I aim for a constant water content.