I'm using nutes and I have to water it practically every 3 days.
Why are you feeding nutrients already? If you don't know why - stop feeding them. The leaves are probably wrinkled like that from excess nutrients and not from over-watering, those leaves look over rich in N to me.
Watering every 2 or 3 days for a 3 inch pot sounds about right to me - makes sure you fully saturate the pot when you water and don't water it again till it feels 'light'.
Does any one want to take a wild guess on how much longer I should keep it in this pot? How big should it be before I transplant it to a pot 3 or 4 times as big as the one its in now?
What you want to shoot for is leaving the plant in that pot for as long as you can, so the rootball gets time to develop correctly, but before the plant starts showing signs of nutrient deficiencies which is a sign the plant's used all the nutrients in the pot.
I recently transplanted plants from 1L pots (about 4 inch) which had been in those pots from germination. I transplanted 2 at 25 days and the rest (6) at 27 days so about 3-4 weeks for those. I'd say the 25 days was about right for mine, and as the pots were slightly larger than yours, I'd say about 3 weeks would be about right for yours - but watch the plant and let it tell you when it's ready.
Also, you want to pot up to an 'intermediate' pot size, I usually go from a 1L (4 inch) to about a 3.5 litre pot (just under a gallon, 6-8 inch pot) to a final flowering pot size of 6.5L (about 1 1/2 gallon, 10-12 inch).
This time I'm probably going 1L > 2L > 3.5L > 6.5L, mainly because I'm growing more plants and have less room, so the longer I keep them in smaller pots the easier and I can go to flowering in 3.5L pots, once the males have shown pull them and then transplant the females into the larger 6.5L pots which hopefully by the time that happens will reduce down the number of plants which will fit into my space better.
It's not generally advisable to transplant in flower because of the stress it causes the plant (and partially because roots grow much less during flowering than veg) but as long as it's done in the first 2-3 weeks of flowering, before the real budding and flowering begins you can get away with it. The only reason I'm doing it is because of space issues otherwise I wouldn't and I don't recommend others do it if they can avoid it.
An ideal schedule for repotting would be -
4 inch pot (1L 1/4 gal)- 2-4 weeks
8 inch pot (2-4L, 1/2 - 1gal) 2-4 weeks
12 inch pot (6 - 12L, 1 1/2 - 3gal) 1-2 weeks Let roots root out final pot ie get to the bottom and show at the holes then put the plant into flowering.
This is just a general guide, it's not fixed. The timeframes depend entirely on the plants needs, environmental factors, lights and quality of soil and compost and how much nutrient content it has. What's important is that you allow the plant to develop a good sized rootball at each potting stage and then allowing the plant time to root out the final pot before putting into flowering. By following this guide you're feeding the plant nutrients at each pot up and each time the nutrients should feed the plant for about 3-4 weeks. So the earliest you should *need* to start feeding plants is at the start of the second week of flowering.
This is an entirely 'natural' way of growing, allowing the plant to *take* the nutrients it needs and not force feeding it nutrients it doesn't need which leads to plant damage, and allowing the rootball to develop correctly, a healthy rootball is the key to a healty plant and good harvest.
This is probably a lot more information then you needed, but I hope it helps you understand the process and anyone else who may not be sure of it.
