What you received in reply is boiler plate - sorry. If you ask her, or better yet, Dave, "What would be the purpose/point of providing almost 10x as much P than the plant can/will use in your 3-6-12, and almost 3.5x as much in the 7-9-5", I bet you'll get an entirely different answer - probably based on their not wanting to forgo filling a market niche. See Dave's email above. Just below is something I wrote about high-P fertilizers. It should help to explain why anyone would be hard-pressed to come up with even an imaginary situation where a high-P fertilizer (one where the middle number [P] is larger than the first number [N]. Even 1:1:1 ratio fertilizers, like 20-20-20 or 14-14-14 have more P than the plant can/will use in relation to the amount of N supplied by about 2.3x. How Much P is Enough?size>color> Let's first look at the role of fertilizers in general. There are 6 factors that affect plant growth and yield; they are: air, water, light, temperature, soil or media, and nutrients. Liebig's Law of Limiting Factors states the most deficient factor limits plant growth and increasing the supply of non-limiting factors will not increase plant growth. Only by increasing most deficient factor will the plant growth increase. There is also an optimum combination of the factors and increasing them, individually or in various combinations, can lead to toxicity for the plant. From the above, we can say that when any nutritional element is deficient in the soil, plant growth slows. We have a term for this occurrence: environmental dormancy. When the deficient element is restored to adequacy levels the environmental constraint caused by the deficient element is eliminated and plant growth can resumes at a normal rate, as long as there are not additional limiting factors. Continuing to increase the element beyond the adequacy range offers no benefits and can deleteriously affect the plant - often in several ways, depending on the element. Somewhere along the way, we curiously began to look at fertilizers as miraculous assemblages of growth drugs, and started interpreting the restorative (of normal growth) effect of fertilizer as stimulation beyond what a normal growth rate would be if all nutrients were adequately present in soils. It's no small wonder that we come away with the idea that there are 'miracle concoctions' out there and often end up placing more hope than is reasonable in them. In couplet with the hope for the 'miracle tonic' is 'more must be better'. I'll use that idea as the lead-in to my thoughts on high phosphorous fertilizer blends. Among container growers you often find common belief that high phosphorus (P) content fertilizers are a requirement for promotion of root growth and/or flowering. Fertilizer blends like 15-30-15, and even 10-52-10 are sold under names that imply that you actually NEED these formulas for plants to bloom well and to produce strong roots. Lets examine that idea in a little more depth. While anecdotal evidence abounds, there is very little scientific evidence to show any need for such products. I've mentioned in other posts that high-P fertilizers are a historical carry-over from when it was most common for plants to be started in outdoor soil beds, the soil in which was usually still quite cold at sowing time. Both the solubility of P and plants' ability to take it up are reduced in cold soils, so it was reasoned that fertilizing with high levels of P insured that at least some would be available during periods of growth in chilled soils. We know that tissue analysis of leaves, roots, flowers - any of the live tissues of healthy plants will reveal that P is present in tissues at an average of 1/6 that of nitrogen (N) and about 1/4 that of potassium (K). Many plants even contain as much calcium (Ca) as P. If we know that we cannot expect P to be found in higher concentrations in the roots and blooms than we find in foliage, how can we justify the belief that massive doses of P are important to their formation? It is well known among experienced growers that withholding N when all other nutrients are available at adequate levels induces bloom production on smaller and younger plants. Even though plants USE nutrients at approximately a 3:.5:2 ratio (note that N is 6 times the level of P, and K is 4 times the level of P), most greenhouse operations purposely fertilize with something very near a 2:1:2 ratio to limit vegetative growth so they can sell a compact plant sporting pretty blooms to tempt you. Simply limiting N limits vegetative growth, but it does nothing to limit photosynthesis. The plant keeps making food, but it cannot use it to grow leaves and extend stems because of the lack of N. To where should we imagine the energy goes? It goes into producing blooms and fruit. What harm might there be in a little extra P in our soils? First consider that the popular 10-52-10 has almost 32 times more P than a huge percentage of plants could ever use. Even 1:1:1 fertilizer formulas like the popular 20-20-20 are already high P formulas because they have 6.25 times more P (in relation to N) than plants require to grow robustly and normally. Evidence of phosphate overfertilizing usually always includes some degree of leaf chlorosis. P competes with iron (Fe) and manganese (Mn) ions for attachment sites and causes antagonistic deficiencies of these micronutrients. Unfortunately, the deficiency of these elements causes interveinal chlorosis (yellowing), and the first thing we normally consider as a fix for yellow leaves is more fertilizer, so we give the plants a good dose of our favorite bloom-bomb which causes, no surprise - worsening of the condition. I'll close with an anecdote of how I used to fertilize plants with showy blooms before I had a better understanding of the overall picture. I would fertilize with a "bloom-boosting" fertilizer as long as foliage was bright green. As foliage inevitably yellowed, I would then switch to a high N formula until the color returned & start the cycle over again. I THOUGHT that the P was helping with the blooms and the yellowing was caused by a lack of N, which I quickly jumped to correct at the first evidence of yellow. I now understand that the high levels of P were what were causing the yellowing and it wasn't my returning to a high N formula that greened the plant up again, it was the reduction in the level of P in the soil when I stopped using the high-P formulation.color> Al

Yes, may is planting time ;-) What do I have growing...hmmm... I started at the very end of Jan or 1st of Feb some geraniums and crazy daisys, ornamental peppers, dalhias and zinnias. I should not have started the zinnias or dalhias, just got too excited! But, the other three are all very very slow growing! They need to be started around then. I put them under shop lights, so they are all doing ok, surprisingly even the zinnias and dalhias. Out of three full seed trays (72 plants each) I have only lost 5 plants. I have since then, about a week ago started a flat of various types of rudbekia. One is Prarie Sun, beautiful yellow flower with a green centre. Another is a type of double, and I also planted a type that has these beautiful oversized flowers and rusty centres. Two of the three varieties are short lived perennials. This last weekend, I have started marigolds and coleus. I also planted a really neat type of coneflower. it has petals on top of the centre cone. I put those in the fridge though and they will stay there for four weeks to stratify, so they won`t come out until April. I am hoping that by April, I can move them out to a cold frame. Now I have learned about it, I am planning on winter sowing a whole bunch of other seeds. I just got a stand off freecycle. I am thinking of trying some extra coneflower and crazy daisy and rudbekia seeds. (I just can`t get enough of those plants, although many likely won`t flower until next year. I have some purple basil, and forget me nots, and a burgandy blanket flower that I am also thinking about winter sowing, or starting in the cold frame. I also have some green envy Zinnias that will be directly sown in the spring. I have probably spent over a $100.00 so far on seed. I am not sure if I spent it wisely, but I have a lot of varieties that are not the common ones, and cost a little bit more. I figure though, I will get about 500 plants out of it by the end, so, by the time you add up the cost of the other supplies to grow them, perhaps it will work out to 75 cents a plant. Even if some don`t bloom until next year, that is still a pretty good value considering they can cost $7-14 at a nursery! I am really interested in seeing how the winter sowing thing goes. It will open up the door wide on what I can start next year. There is only so much you can grow in the house! So, what are you planning on growing...

If you examine the ingredients list on a bag of Miracle Gro potting soil, I believe that you will find that it contains "locally" obtained ingredients. That implies that the quality will vary with manufacturing location. I have had bad results using Miracle Gro potting soil bought in the Chicago area. Last year, I used a home made mixture of 2/3 peat moss and 1/3 perlite (by volume) without lime and it worked fine, but, note that my fertilizer solution contained calcium. I buy peatmoss on sale at Menards for about $5 per 2.2 cubic feet. Perlite is $10.23 per 4 cubic feet at http://www.bfgsupply.com/UserFiles/2008Catalog/5_Soil.pdf. That is cheaper than any premix you can buy.

I would say that in order for something to be considered gritty mix, it needs to be good and porous, and needs to stay that way. Basically, it can't have decomposable contents that will clog the pores as they break down, thus making it not gritty anymore. Mixing stuff in with bagged potting mixes would fall under that category. I'm not saying this in order to put anyone's mix in some elite category, or exclude others from some status or gritty mix club, but it's important that what is called gritty mix is actually what a lot of us think of as gritty mix. Otherwise, the advice you may be given could lead to problems, such as the advice I gave above, assuming that when you said gritty mix, that it was actually gritty mix. Joe