I changed over to using mostly FP several years ago. I continued with adding gypsum to the gritty mix as a Ca source out of habit, but the fact that FP contains both Ca and Mg had me wondering if the gypsum & Epsom salts regimen were necessary with the FP. I mentioned last year that I'd try a few plants in the gritty mix w/o using gypsum and Epsom salts. So far this year, when anyone asks, I've noted that the plants in the gritty mix w/o the gypsum/Epsom salts regimen are doing fine with only the FP. You might extrapolate that you don't need to use gypsum or Epsom salts when using the gritty mix and FP 9-3-6, but I haven't been very vocal about it because I only have a few plants I'm watching. I guess I would say try it & see what you think, keeping an eye out for any sign of a Ca or Mg deficiency; or be safe & use them (we know they work) until I and others are certain you can abandon the practice. This would only apply to fertilizers like FP that have Ca and Mg in them, and only to the gritty mix. The 5:1:1 soils or other soils you make yourself should still include dolomite (remember, it's a pH thing, too). Al

Oops - I missed Xuan's question! ".... if I give some gypsum to my mix, in addition to slow-released fertilizer... I'm assured of adequate nutrients to the plants. Right? Wrong?" Mmmmmmm - maybe a little of both. The following are parts of a reply I just posted a few minutes ago on the soil forum: We cannot bake a plant grow or maintain vigor at something beyond its genetic limits by adding more of something that is not deficient or limiting. Anything soluble in the soil solution that is in excess is counterproductive. As in the diet of animals there is an ideal balance of protein, carbs, nutrients, etc. The same is true of the balance of plant nutrients in soils. Both the concentration AND ratio of these nutrients to each other are an important consideration if we expect to be able to coax plants to grow at or near their genetic potential. From the department of redundancy department comes the fact that adding more of anything than is necessary to make it a non-limiting factor is counter-productive. ************** There are three basic questions we should take into account and be able to answer yes to, when we develop our nutritional supplementation. They are: * Am I supplying all 13 of the essential nutrients plants normally get from the soil? * Are the nutrients present in a ratio that is favorable to each other. * Is the o/a level of dissolved solids (EC/TDS) in the soil in a favorable range. If you cannot answer 'yes' to all these questions, your plants will only be able to grow within the limitations the imperfect conditions allow. Don't panic. ;o) There is no need to get technical to the nth degree. You can be pretty sure you're doing close to the best you can do if you familiarize yourself with the nutrients plants need, then read the labels to make sure your plants are getting them. Using a 3:1:2 ratio fertilizer will go a long way toward ensuring that you are supplying the primary macro-nutrients in a favorable ratio. Using a fertilizer like FP 9-3-6 ALSO ensures you are supplying the secondary macros AND the micronutrients in a favorable ratio, that being in a ratio that approximates that in which the plant actually uses these elements. The main nutrients to look out for are Ca and Mg. MOST soluble fertilizer lack these elements, which is why dolomitic lime is such a valuable commodity for those of us who make our own soils. When the increase in pH caused by the lime is a little more than soils like the gritty mix can tolerate, and when our fertilizer doesn't provide it (Ca), there is an advantage in using gypsum (CaSO4) as a Ca source because it doesn't raise pH. When you need to use gypsum as a Ca source, you usually also need to use Epsom salts MgSO4 as a Mg source. Here again we need to look to not only the availability issue, but also to the RATIO. Supplying only Ca (gypsum) can make Mg less available/difficult to absorb, so we need to be sure that the ratio of Ca:Mg is favorable. When I first discovered FP 9-3-6 a few years ago, I got really excited for YOU guys. I was already taking appropriate steps to ensure all my plants nutritional needs were being met by doctoring my MG fertilizer. I was VERY pleased with the results of what I had done with the MG, and didn't notice any difference when I switched to the FP. It made me happy for 2 reasons. 1) I didn't have to mix all the other 'stuff' into my MG fertilizer; it really simplified things, and 2) I didn't have to teach you guys how to do it. ;o) Don't be shy about asking questions if you don't understand, Xuan. I'm betting Demeter won't mind - especially since it's so on topic. Al

Let's keep it straight for other readers who might be researching these mixes. Dolomitic Garden Lime goes in the 5-1-1. Gypsum goes in the Gritty Mix. When using Gypsum in your mix, you add Epsom Salts to your fertilization water. However, as Al has many times stated, if you have a fertilizer that supplies all the essential nutrients, then you don't need to add the Gypsum to the Gritty Mix. Since you are purchasing or have purchased Foliage Pro, you don't need Gypsum necessarily. As for the peat moss questions....I advise you to make a Lime peat moss mix and to simply test the pH of the saturated mix. Then you can tell us how Lime affects the ingredient. Josh

Adding Epsom salts to your plant w/o adding calcium (Ca)can create a deficiency of Ca (Search calcium magnesium antagonistic deficiency). The effect of adding 1-2 tbsp of Epsom salts to a gallon of water and then applying it to your plants is virtually the same as adding 1-2 tbsps of fertilizer to the water and applying it. This will raise the TDS (total dissolved solids) and EC (electrical conductivity) levels of the soil solution to extremely high levels, and can cause plasmolysis (fertilizer burn) - especially if the application is close to your regular fertilizing time, because you have the Epsom salts + your fertilizer salts + residual salts in the soil. 1-2 tbsp/gallon doses also virtually assure a Ca deficiency unless you add Ca at the same time. You should be sure you have a Mg deficiency before you use MgSO4 (Epsom salts), or using it is always counter-productive. When you DO have a Mg deficiency, 1/8 - 1/4 teaspoon per gallon of water along with your regular fertilizer (that does not contain Mg) is enough to alleviate the deficiency. Al