Having used Nigari in commercial soy tofu production here are some thoughts on the Japanese tiny, yet sweet tomato production linked in a video above. (Nigari is made from sea water, yet most sodium chloride is separated out. The principal ratios by weight are approximately: 10 Mg:1 Na, 5 Mg:1 K, 2.5Mg:1 Ca, 40,000 Mg:1 + trace minerals. Actually there is 5+/- times the volume of Magnesium to Calcium, but Magnesium being relatively light it's weight ratio is less than 3 times greater. So Nigari is a distinct technique than western greenhouse salt useage.) What reduced the fruit size? Increased conductivity can account for miniaturization, as well as fruit's elevated sugar content (as referenced above). What improves conductivity without upsetting plant physiology? Magnesium's double charged ions, with itself being so relatively light in weight brings many counter-ions. The ions buffer & apparently keep pH within plants criteria. Nigari is mostly Magnesium salts of chloride (MgCl2) & sulfate (MgSO4) ; with additionally: MgCO3+ (a bicarbonate), MgCO (a carbonate), MgBOH4+ (a borate), MgOH4+ (a hydroxide) & MgF+ ( a flouride) Is Nigari fed to tomatoes developing leaves & roots? No, as chloride impedes nitrate uptake & nitrogen is important at this stage. When would Nigari first be beneficial? At fruit set the dynamic of Calcium, Magnesium & Potassium are important. It is Magnesium that aids plant utilization of Calcium ions, keeping it from precipitating out & so boosting level of circulating Calcium. It, Ca+, is driven by water to the cells' membranes & inside for critical cell division. (Build up of Calcium is desirable, yet when fertilize too heavily with Phosphorus &/or Potassium the Ca+ can be present but actually unusable. In effect when P &/or K high total dissolved solids raise the electrical conductivity it is different than Nigari's ionic effect.) What other tactic is interesting? In addition to Nigari the grower stressed rice straw mulch to dry his soil & showed an arid handful. This water limitation would lower leaf transpiration & there is less water demanded by foliage; so, Ca+ being water driven accumulates in the fruit. Also, compounding this redirection of Calcium is the fact that increased conductivity reduces water uptake; once again keeping the fruit from plumping to normal size, even though the tomato seed used was of a standard variety. The practical result is more fruit cell division indicating better productivity in quantitative yield & of course no blossom end rot from calcium deficiency. Can Epsom salts do the same thing? Apparently not, even though it is a practical Magnesium source. (Although Epsom salts can be used to coagulate soy milk it does not produce the same structural & flavor tofu as Nigari.) How much Nigari should be used? If some one can calculate that please tell us.

To the plant, nutrients are nutrients and it doesn't matter where they come from. But an organic soil will provide those nutrients over a longer period of time. Not arguing organic here, just saying that gradual and constant nutrients make a healthier plant than irregular cyclical nutrients do. And a constantly healthier plant will make a better fruit, organic or not.

One thing to keep in mind about compost, is that although the NPK of it is pretty tiny, we do always use a lot of the stuff. But it still takes time for those nutrients to appear. Now, if your season is short, compost may end up supplying a lot of the necessary nutrients. But compost applied at the beginning of a nine month season won't suffice in the long run. I've seen it happen. For me, with hot summers, which accelerate decomposition, it's pretty much gone by August. I guess you can define fertilizer in many ways. Shovels are really good for growing plants, so they must be fertilizer, right? But yes, they aren't nutrients. People like to claim that eggshells are wonderful fertilizer for plants, because they supply calcium. Yep, they contain a load of calcium. But they don't supply it to plants for a long long time. They are eventual nutrients, not right now nutrients. Hey, we could get all our necessary minerals by just swallowing rocks, right? Eventual nutrients. That's true that most organic fertilizers are eventual nutrients, which does make nutrient management a little tricky. If you have a problem, you may not be able to fix it very fast. That's correct about 3-1-2, and also correct that you shouldn't get too particular about NPK mixes for peppers. Give them some N, P, and K, and they'll do fine.

I'm just visiting from the lawn care forum to see what you folks have been up to. Back in 2002 to about 2007 I hung out here, but then moved primarily to lawn care. Anyway this topic caught my eye, and this sentence has me wondering: Is there any study that documents how much NPK is actually delivered to the soil when compost is used in typical volumes (e.g., one, two, three inches of top dressing)? Being a lawns guy now, where would you use 1-3 inches of top dressing? The answer, I presume is in a flower or veggie garden. At those amounts would you still call it top dressing? Anything 1 inch or deeper is mulch to me. In the amateur lawns biz, we have always talked about using no more than 1/4-inch of compost as a topdressing. Why? Because any more and you seriously risk smothering the turf. I have pictures of a lawn which smothers their St Augustine lawn every other year, and they pay for it the rest of the growing season. So 1/4-inch it is. How much is that? That is 1 cubic yard per 1,000 square feet. That is roughly 700 to 1000 pounds depending on moisture content. If you are limited to 1/4-inch for a lawn, the cost of that (in my area) is $50/yard for the compost and $100 delivery up to 3 yards. For 3 yards delivered that's $250 or $83 per yard (or per 1,000 square feet). Then you get to spend the weekend behind a shovel and wheelbarrow applying the stuff. Or, you could apply organic fertilizer instead of compost. The organic fertilizer I like for now is alfalfa pellets, but I'm warming up to Tractor Supply's floating catfish food and will try that later in the season. The application rate for these fertilizers is 15 pounds per 1,000 square feet. Alfalfa pellets cost $12 for 50 pounds at the local feed store. Cost to apply then is $12/50*15 or $3.60 per 1,000 square feet. In order for compost to be a favorable 'topdressing,' it's going to have to have a lot more benefit than it seems to have. Yes I have a compost pile, and it gets used under the roses when we don't have chipped tree mulch. Also under the roses I use both alfalfa pellets and corn meal several times during the growing season. Our roses have not had chemical fertilizer...ever.