Based on the density of typical soil, the amount of an element required to raise the concentration in 100 sq ft to a depth of 1 ft by 1 ppm is about 5 grams (1 oz = 30g). So, if you had a 100 sq ft garden and you wanted to raise manganese by 2 ppm you'd need about 1/3 to 1/2 oz Mn total. This is just to give you an idea; I wouldn't expect you to go out and find that amount and mix it in a foot deep.

Are you seeing symptoms of deficiency in your plants? If so, you might need more immediate treatment. If not, you can gradually improve things.

Which brings me to my next point. Compost provides all the micronutrients, so unless your soil already has too much organic matter, just add compost. Have you been doing that, and how much, how often? For most soils you can add 1-2" per year, either dug in or as top dressing during the growing season.

If you are not making compost, consider starting. Kitchen waste, especially, is high in nutrients. If you buy compost, don't always get the cheapest. Tests show that you pretty much get what you pay for with compost. You don't have to get the most expensive either. The middle ground is usually the best value.

Thanks tox!

This is exactly what I'm looking for. Help me a little bit with the math though. First of all the dilution of my plant juice for spraying is 1 tbsp per gallon or 256 to 1. Should I assume the concentration analysis is full strength or diluted? Please stay with me on this because I feel like I'm close to an answer to my problem even though it makes my head hurt. It seems like your numbers were full strength without dilution factored in.

btw I stopped composting this year because it was too much work. It's so dry here it takes forever for anything to break down. This year I made a peat moss/manure mix instead, possibly in error. Many vegetables just struggled and flowers barely bloomed

You may have had too much browns in your compost mix and tied up the nitrogen in the soil. If the manure had straw or especially sawdust mixed in, it could consume nitrogen while it decomposed. Also, peat moss is good for adding organic matter/texture/drainage etc. to your soil, but it doesn't have significant nutrients. Compost is not considered a fertilizer (it's a slow release one in my book) but it certainly has more nutrition to offer than peat moss. If you're in a hot dry climate I'm going to guess the peat moss is imported from far away. If that's the case, that's one more reason to stick to local compost/manure, etc.

As for the plant juice, it should say on the label whether the analysis shown is for the concentrate or diluted form. If not...Is it giving it in units of percent, mg/L, ounces per 100 gallons, ?? This may help to answer the question. Also, you could contact the company and ask.

tox

The manure is bagged home center manure and the juice label analysis is %. I think the assumption to be made is that it's for the concentrated form because that's a fixed variable and diluted results would be subject to the accuracy of the dilution and would vary but I'm going to ask the company to satisfy my curiosity. Thanks for the reply

That may explain the very low % levels of minerals. Given those percentages, it's not a significant amount of minerals in terms of adding it to soil to raise the soil concentration. Let's figure the amount of one mineral in a tablespoon.

1 Tbsp = 15 mL = 0.015L

Assume the density is the same as water so that equals 15 g also.

15g concentrate x 0.125% Mn = 0.019g or 19 mg Mn

If diluted into 1 gal, 1 gal = 3.8L

19 mg/3.8L = 5 mg/L or 5 ppm Mn

These levels are low enough that they're not going to significantly increase concentrations of the minerals in the soil. In my amateur estimation it seems better for a potted plant or for foliar application (IF these minerals are absorbed that way, I don't know from Adam). You could certainly water transplants with it but any water or rain later will tend to wash away anything still in the soil water solution.

Thanks tox

You have given me a basic understanding of what I'm dealing with and I appreciate it. I think I will give the soil a couple more applications of the juice and then have the soil tested again. Hopefully my NPK will have come down and the Mn and B gone up. I guess the juice just has to be re-applied over and over because of the washing away effect. Oh well I have to use up the juice anyway, right?

Here's the reply from the company

Thank you for your email. The Guaranteed Analysis is based on the concentrate in the bottle, before dilution. Proportionally, enough of the product will be applied with the active ingredient to make the product effective.

Regards,

Angie

Central Garden

800-265-0761

Cooperative Extension in California does not offer soil testing. You're on your own.

If you really want to raise the concentration in the soil significantly, this product is not the way to do it, based on the math I showed. Note my earlier post that the levels in this product are not going to significantly affect concentrations in soil.

Get some manganese sulfate fertilizer if you actually need it. But, again, if your plants are not showing symptoms of deficiency, it's probably because plants can't read and will adapt to the conditions. Regular applications of compost will provide what plants need.