Beginner Gardening: Good Growing Practices - an Overview for Beginners, 1 by tapla

tapla wrote:
Peg - I talked upthread about the importance of following a good nutritional supplementation program. I'm not sure if it was on this thread or somewhere else where I cautioned against using a little of this and a little of that because someone thinks it might work. Far more often than not, those elements or compounds aimed at supplying a singular nutrient (in your case with the potash it's K [potassium]) end up being a limiting factor, rather than a benefit. If your plants don't exhibit recognizable symptoms of an actual K deficiency, adding the extra potash is going to unnecessarily contribute to what is dissolved in the soil solution. The more there is dissolved in the soil solution, the harder it is for plants to absorb water and nutrients. PLUS, if you have WAY too much potash (which isn't hard to do) it can cause antagonistic deficiencies of other nutrients.

What makes a fertilizer appropriate for various plants doesn't have anything to do with what's ON the box (label). It's the NPK %s and the ratio of nutrients to each other that determines what's appropriate. There is nothing special in azalea fertilizer that makes it particularly good for azaleas. It's probably 30-10-10 with urea as the nitrogen source so the urea can produce an acid reaction as it breaks down.

Hi, Jo - thanks for the kind words. Who says that cacti or succulents prefer 2-7-7 or something similar? (I'm smiling - not being confrontational - sort of a poke in the ribs.) They USE nutrients in about the same ratio as other plants, so it's difficult to envision how someone could make a case for providing nutrients in a ratio other than that which they use. We know that plants use about 6X more N than P, and about 3/5 as much K as N .... this is on average, but the range of variation is very small.

I gave Nitrogen, because it is the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19 (16) 1/6
K 45-80 (62) 3/5
S 6-9 (8) 1/12
Mg 5-15 (10) 1/10
Ca 5-15 (10) 1/10
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06
Cu 0.03
Cl 0.03
M(olybden) 0.003
To read the chart: P - plants use 13-19 parts of P or an average of about 16 parts for every 100 parts of N, or 6 times more N than P. Plants use about 45-80 parts of K or an average of about 62 parts for every 100 parts of N, or about 3/5 as much K as N, and so on.

If we use 2-7-7 as an example, we know that because all plants use about 6X more N than P, that 2-7-7 supplies about 10.5X as much P as the plant can use relative to N, and more than 5X as much K. As I mentioned to Peg earlier in this post, and because we all fertilize as a function of the plant's N needs, the excess P and K will unnecessarily contribute to what is dissolved in the soil solution. The more there is dissolved in the soil solution, the harder it is for plants to absorb water and nutrients.

It's only when I'm intentionally trying to manipulate a plants growth habit that I use a fertilizer OTHER than one in a 3:1:2 ratio, and that is for ALL my plants. For review, 3:1:2 ratio fertilizers include 24-8-16, 12-4-8, 9-3-6, and a fertilizers RATIO of nutrients to each other is far more important to sound nutrition than its NPK %s.

I think there are not many ways to become a good grower. The best way, is by paying your dues and gaining a good understanding of the intricacies of how plants grow and interact culturally with their surroundings. That takes time. In the meanwhile, new growers can advance in their abilities very quickly by following the direction of someone who does understand some of the intricacies. This may not make a new grower proficient in the true sense of the word, but it can help circumvent a lot of initial frustration and increase the satisfaction:effort quotient while in the process of refining understanding.

All of the information you need to be an accomplished container grower fits together like a jigsaw puzzle that is under assembly. Each of the pieces are somehow connected to the other pieces - either directly or extraneously, but they ARE all connected. If ever you’ve put a jigsaw puzzle together, you probably remember that it’s easier when you try to get the outer 'frame' together first. This outer frame is representative of an understanding of the most basic knowledge that is needed for success. Of the basic knowledge, most important is an understanding of how the soil/water relationship works & how the individual soil components interact as they relate to the whole. Basically we need to understand that a healthy root system is required if the plant is to be healthy. Then, and easier to understand are a very few additional issues like the importance of light to your growing experience, how fertilizers work and what fertilizer is most appropriate ……. We also need at least a very basic understanding of how some of the other cultural conditions might affect plant growth/performance. Once the grower has this essential understanding in grasp, that is to say the framework of the growing puzzle completed, assembling the rest of the pieces will occur at a rate exponentially faster than the rate at which you progressed at the outset of your growing experience. Unless this basic framework is complete, we’re basically relying on trial & error, which is certainly no short cut to success.

Al