@j_kraut FWIW, how fast your trees grow depends on 2 things. 1) Their natural vigor, which is a genetic trait. 2) Their vitality (health), which depends on the cultural hand you deal them because it's a measure of their ability to deal with that hand.
Let's say that every cultural factor affecting your plants' growth can be reflected on a scale of 1-10, and 5 represents the sweet spot for every factor. Ideally, you're able to keep every factor at level 5, and maybe 4-6 is still quite acceptable. It's when any cultural factor creeps toward the limit of what the plants are genetically programmed to tolerate that you start to see unwanted obstacles to growth rate, vitality levels, appearance, the plant's ability to defend itself, ... . So, choose what plants you grow based on how close you can come to satisfying their cultural needs. Plants with a higher level of genetic vigor are called vigorous because they are capable of dealing with a wider range of stress than plants with less natural vigor.
As you can see from Liebig's Barrel below, it only takes a single cultural factor being close to what the plant is programmed to tolerate to throw a monkey wrench into your 3-4 year plan. The barrel says the plant is suffering from a nitrogen deficiency ...... and nothing can fix that, no matter how perfect all other cultural conditions are, except increasing the supply of nitrogen. Not better light or more/less water, or changing to a better grow medium. Once the N deficiency is fixed, it looks like perhaps temperature or boron will need to be fixed. It's always the most deficient cultural factor that limits growth.
Are you interested in some reading suggestions to keep you busy over the winter months?
Al
