On another point, remember that nutrient availability is directly proportional to pot size (big pot=more nutrition), I know that sounds obvious but people still over-do it, feeding too much 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 true deficiencies (not enough nutrients provided) & over-fertilization pH lock-out deficiencies (nutrients are being provided, but cannot be "accessed") that are caused by over-feeding, or very rich "hot" soil mixes, and that lead to a build up of mineral salts in the soil, throwing the pH out, and making one or more nutrients unavailable to the plant, causing its deficiency. In extreme cases this will lead to a multi-nutrient blockage which then makes diagnosis even harder, as you are dealing with multiple symptoms. 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 (& some "experienced!") growers do which is to assume the plant is suffering a deficiency from scarcity of nutrients & feed it even more. Using a very rich, highly fertilised 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 levels of salts even if the grower has not started to "over" feed them with nutrients yet. If people keep applying their "fixes" for problems they aren't even sure WHY they have, they will spend half of their lives in a problem forum discussing what latest "fix" is going to get them out of their latest self-inflicted mess.