Nutrient availability is directly proportional to pot size, (big pot = more nutrition), I know that sounds obvious but people still over-do it, either feeding a plant that doesn't need it, feeding too much, or too frequent in the early stages. If you have used the correct size pot for the plants stage of growth, and have a good quality horticultural potting soil/mix that has sufficient nutrients, adequate drainage & aeration, then deficiencies should not appear early on unless something else has gone awry. This is where it is important to be able to distinguish between deficiencies where not enough nutrient(s) are being provided & pH lock-out deficiencies (nutrients are being provided but cannot be "accessed"), that are caused by the soils pH becoming imbalanced. This can be caused by the over-zealous use of chemical fertilizers and can lead to a build up of salts in the soil, which cause the pH imbalance, making one or more nutrients unavailable to the plant, causing its deficiency. In extreme cases this will lead to a multi-nutrient deficiency which then makes diagnosis even harder, as you are dealing with multiple symptoms. If the build up of these salts is severe, the plant will suffer as it tries to address this, through an osmotic response, which draws moisture out of the plant in an attempt to fix the problem. This is why flushing is beneficial if you are suffering this, to leach out those salts. There are ways of determining what the culprit is, such as testing the soils run-off, to determine its pH level, and then taking the appropriate action, instead of what most inexperienced growers do, which is to assume the plant is suffering a deficiency from scarcity of nutrients & feed it even more, or start applying fixes without knowing the cause of the problem. Using a very rich, highly fertilized soil is never a good idea as they can have far too much nitrogen in them, which can cause burn, & a very high EC (salt) level, & so can still have high salinity levels even if the grower has not started to "over" feed their plants with nutrients yet. Water thoroughly until you have run-off, I do not mean torrents, as this would be futile & leach out nutrients, you want just enough to know that every part of the medium is sufficiently hydrated. Obviously, you don't have to water like this everyday, it becomes easier to gauge as you become accustomed to understanding the amount of water your plants require. This practice can also be beneficial as it will allow you to constantly monitor the pH of the soils run-off. Wet & dry cycles do stress the plants, and exacerbate any issues you may have to do with salt build up. Don't get me wrong, a few millimetres of dry soil on top isn't going to do any damage, but I have heard talk of not watering until the soil is coming away from the sides of the pot, probably taking days, even up to a week to get to this point. I do understand the reasoning behind why people insist on letting their soil dry out (roots "explore" the pot to "seek out" moisture, thereby increasing growth & mass, etc.), but the negative aspects of this practice far out-weigh the positive; if you have a good quality soil-mix, with adequate provisions for drainage & aeration, then a good watering schedule will not cause root rot, or negatively impact root growth, or starve them of oxygen or cause any of the other problems people fear UNLESS other factors are at work, such as soil compaction, excessive over-watering, or letting the pots sit in water for too long. And remember, oxygen is supplied to the roots by complex processes & reactions, and is not just derived from the air, because you let the soil dry out.
. Your plants look pretty good to me. Just a slight adjustment will bring her to full throttle. She looks like she could use some more Mag and P. She is stretching and pretty thin that would be a sign of P and the yellowing on the tips is a sign of Cal-mag. Yes, do let the soil dry out just before she wilts. That would make your roots bigger and stronger. Bigger roots = bigger, stronger plants. Keep in mind you only want to allow your soil to dry out that much only in Veg. In flower you don't want to exceed 70% dry soil.A picture of the whole plant would be helpful.
