Just check for strain on the plant. You'll need to measure the plant top to bottom and measure three to five branches that you can remember. Write it down. I use a small notepad. This way you can go back and measure again in a week or so. Do this repeatedly to notice a grow "pattern". Once you have that you should have a great idea of when the plant stops growing and when it is under stress. Stress symptoms include but not limited to- Dark leaves, Stunted growth, Poor nutrient circulation... shown in stalk by touch. Instead of feeling rough it will feel very soft. Hope this helps. Oh. If you're planning on doing the outdoor thing next year.. I suggest going to the hardware or gardening store and getting a soil test kit to show you the levels of nitrogen, phosphorus, and potassium in your soil. This is the number one mistake made by new outdoor gardeners. To fix this you will have to nute the shit out of it... or... use buckets. Buy some fox farm soil. Get the plants to about 8 inches inside then move them to the pots. They should do great with minimal nutes. But they do help if you wanna use them. Buy a light meter as well. I have an all in one that does moisture, Light, and PH. It's a life saver. Get one use it.