Epsom salts is a chemical compound (MgSO4). Coffee (and tea) are known for their toxic alkaloid (caffeine) content and their allelopathic affect on plants as well as autotoxic (poison to their own seedlings) effects on future generations. Caffeine interferes with root development by impairing protein metabolism. This affects activity of an important bio-compound (PPO) and lignification (the process of becoming woody), crucial steps for root formation. We also know that the tannins in both coffee and tea are known allelopaths (growth inhibitors). I used one fertilizer that supplies all the essential elements plants normally get from the soil (Foliage-Pro 9-3-6), but it's a soluble synthetic and not a fit for your all organic approach. I respect your desire to remain all organic, but fertilizing efficiently (without over-supplying some nutrients and under-supplying others) is much more difficult, in part because you usually need more than one fertilizer to cover all the bases, and there is no real way to know when the nutrients locked in hydrocarbon chains will become available; this, because you depend on soil microorganisms to free the salts plants use as building blocks - the same salts that are efficiently and precisely supplied by soluble synthetic fertilizers. Unfortunately, changing cultural conditions cause soil organism populations and their activity levels to vary widely in container culture, which has a significant impact on nutrient availability. Al

Non-conventional.....crack three eggs in the pot every three or so weeks and stir it in a little. I have experimented many times showing eggs to be just a touch less effective than MG. On another note....the extended feeding ferts by Scott's et al. are only time-released with respect to nitrogen via the coated urea...to my knowledge....and thinking the time-release is based on water contact. The rest of the fert blend is just micronutruients and a regular fert chemicals. I believe the only exception is Osmocote, and I don't know the manufacturing process there, but don't think that Osmocote has any micronutrients....would need to check the label. Btw, IMO, the ferts out there are pretty much the same chemicals acquired and blended based on supply and cost...nothing new. I can say that the water soluble inorganice blends, i.e. Miracle Gro, have some better quality ingredients for better solubility.....

Hi Judith: Muriate of Potash is potassium chloride, salt index of 116.2, very high, that's the stuff we use to de-ice in zone 5a winter. I would not use that stuff on any plants. Sulfate of potash has salt index of 43, NPK 0-0-50, plus the sulfate part which makes it more water soluble. The safest potassium with no salt would be chop-up banana peels soaked in water. Banana peels NPK is 0-3-42. MiracleGro Moisture Control potting soil (blue bag) already has slow-released fertilizer for 3-months, no need for additional fertilizer. What it doesn't have is calcium, essential for root-growth. I put granular gypsum bought from Menards on top of my roses ... after 1 month of spring rain, that didn't dissolve. Gypsum is 22% calcium, and 17% sulfur, but it varies with brand .. some brand contains less sulfur, and never get dissolved. The soluble gypsum from Kelp4Less dissolved easily in my tap water, pH 8, so I suspect there's more sulfur % in that one. The instant green-up and deepening of bloom colors most likely is from the sulfur %. I would dissolve the gypsum you bought from the feed store at the rate of 1 tablespoon per gallon, if it doesn't dissolve, then is best used in the ground. Roses Unlimited recommends mixing in 1 cup of gypsum in the planting hole. If the gypsum you bought from the feed store still doesn't dissolve, I would put less than 1 tablespoon of vinegar per gallon ... any more roses will wilt in the heat. Putting vinegar in the heat is risky, less is best. So far 4 studies pointed to calcium and extra potassium as essential in best root-growth: U. of Kentucky with Peters 20-10-20, same with U. of Mass with marigolds. Two additional studies: one with hydroponic lettuce, with the best result Masterblend 20-18-38 with added calcium nitrate and magnesium sulfate (Epsom salt). This was done hydroponic, no soil, thus the logic for Epsom salt. Another experiment is done by Ohio Link NTD center on New Guinea impatient flowers. Here's the tested ones: Peters-water-soluble 20- 4.4 -16 Daniels-soybean-base 10- 1.8 -2.5 Osmocote 3-month release 15-4-10 5-month slow-release 15-4-10 The best performance is Peters-water-soluble (NPK 20-4.4-16). The worst performance is organic soybean base, too little potassium. Potassium mobility is a 3, somewhat mobile, and gets leached out. Potassium is essential for root growth, that's the only extra fertilizer one needs besides calcium for best root growth. MiracleGro potting soil has plenty of nitrogen, I get a gigantic dark-green Excellenz von Schubert from a band, I had to chop off 2 feet of growth, before planting in ground. The safest bet: chopped up banana peels soak in water for potassium, and gypsum powder at 1 tablespoon per gallon (low salt index of 8). Plus MiracleGro Moisture Control potting soil (blue bag), which already have slow-released fertilizers. Less fertilizer is best for young bands. Below is Gene Boerner, bought from Roses Unlimited end of June sale, fertilized with the above approach. Picture taken few days ago, so it's 3-weeks of growth:

Thank you, Alan. But back to the "best fertilizer" question. I also grow African violets and orchids, fairly seriously. Both are rather picky (why else would I bother). Some of the best advice I've gotten from the related communities is that what the best fertilizer is depends very much upon what you're starting with. And I've also experienced the results of not taking that into account: the decline of a very sensitive AV that is my canary in the coal mine, that's been fed on spring-fed lake water (very neutral but likely lacking in micronutrients) plus a formula that claimed to be "African Violet Fertilizer." My spring-fed lake water is probably not far from reverse-osmosis water. In any case, it likely lacks the micronutrients that are present in well water or perhaps "city" water, depending on the city. Some get it from wells. Others get it from rivers. In other words, there are many possible variables. In short, to determine your best fertilizer, you need to know what's already in your plant's environment, or at least make a darned good guess based on effects on your plants, and adjust appropriately, hopefully in time. This might sound discouraging. The up side is that after years of not knowing anything about most of this, most of my amaryllis bulbs at least are still going great guns, and rewarding me hugely, year after year. The challenge is how to help them do even better. I'm up for it.