How To Mineralize Your Potting Mix
Want to grow high-Brix plants but also want the convenience of store-bought potting mix? Here’s how to add a mineral boost to your mix!
Carbon, oxygen, and hydrogen are 93% of your plant. Sugar [glucose] is C₆H₁₂O₆ — carbon, hydrogen, and oxygen. Now you know why plants produce sugar. It’s stored nutrition that becomes 93% of their bodies. Brix is a way to measure sugar production. Once it goes to 13% and above she has enough to keep that 93% fully healthy. Natures way. — Gee64/420Magazine
So if you’ve read anything in this newsletter, you may know that my ultimate goal is to have high-Brix plants. This isn't only just for taste reasons, but is also for plant health reasons. High-Brix plants typically have way fewer pest & disease issues which is important to me and I’m sure to you reading this as well.
Whether you make your own potting mix or prefer a generic one from a garden center, one thing that will help to raise Brix is to provide the minerals plants need.
These are what we want to focus on for adding to our potting mixes because they are lacking in every single mix:
Calcium
Trace Minerals
Funny enough, marijuana growers were figuring all of this out years before it seemed to hit regular home gardening forums, (and prior to them, grape growers and farmers.) Some of the popular posts were by a person going by the user name “Doc Bud”. He came up with a mineral formulation that he added to all of his potting mixes which greatly increased Brix in his marijuana plants. The following is based on that and other information as well.
Minerals are very important to plants, which should make sense as they are meant to grow in dirt. Can’t get more mineral-based than that! In fact, one of the most important components to plants is rock. There are plants called lithophytes that grow directly out of rocks very happily with no soil at all, just living off of sunlight, rain water, and the minerals they extract from rock. They may grow a little slower than a plant in soil, but they can subsist in rock quite happily. The reason for this is that rocks are full of microminerals. However, most potting mixes on the market are not very mineral-based at all. They are more based on the litter layer in a forest that help to feed soil microbial life but do not contain any of the mineral layer that roots grow in. That layer is very important! This is where chemical agriculture has come in with inputs that make plants look green and they technically grow, but they are by no means providing the comprehensive mineral compounds available in nature. This is by far one of the reasons why we can have a green, growing plant, but also have insect or disease issues.
So, how can we correct this potting mix deficiency? Truthfully, it is hard to replicate all of the advantages of in-ground growing into a pot. But there are a couple of things that can help. One of which is to make our potting mix as mineral as possible. We can take more control over that by making our own potting mixes. Perhaps we don’t have time or ability for that. Well, then at the least, we can add in minerals. That is where this article comes in to help with the following mineral mix that provides the needed calcium and trace minerals from rock or related sources.
Doc Bud’s Mineral Mix:
6 parts high calcium Limestone (NOT dolomite! It should be about 90% calcium carbonate) (Slow-release calcium)
5 parts Soft Rock Phosphate (Steady release calcium & trace minerals, phosphorus balances the sulfur in gypsum, & the said sulfur helps breaks the bond between the calcium & phosphorus in the soft rock phosphate.)
3 parts Gypsum (Fast-release calcium)
1.5 parts Azomite (trace minerals)
All of the above are usually in powdered or pelleted form. Note that powdered forms are usually more quickly plant available than pelleted forms. Though, pelleted forms may last longer than powdered forms.
You can either premix it all together well so you have a mineral combo ready to go; or you can add these individually all together into your potting mix and combine them in it directly. Be careful of any dust while mixing, you do not want to breathe it in!
Add two cups per standard-size bag of potting mix (usually around 1.5 to 2 cf.) Or 1/4 cup per 5-gallon pot of potting mix. You can mix it directly into the potting soil or top dress with it and water it in well.
This mineral mix will work best in potting mixes with the fewest amendments as possible. If you have a lot of organic matter in your potting soil, add about 1/2 cup more of the mineral mix to the bag.
This is something that may be handy to have already mixed up and stored in a bucket or other closed container so that it is ready to go. It can then be added whenever you up-pot, re-pot, or an amount sprinkled on at various times throughout the growing season. However, premixing large amounts could generate a lot of powder into the air which isn't desirable for your lungs, layering them into your mixing container will help to limit the amount of mixing needed. I am also including the breakdown below for adding them individually directly into the potting mix if that is preferred.
For your convenience:
If you prefer to mix it in individually, these are the amounts per bag of potting mix broken down by 1/4 cup to make measuring easier using a single cup based tool:
1 cup Limestone (not dolomite)
3/4 cup SRP
1/2 cup Gypsum
1/4 cup Azomite
This makes 2.5 cups of mineral mix.
These are the amounts individually per 5 gallon pot by tablespoon to make measuring easier with one tablespoon based tool:
1 ½ Tbs Limestone (not dolomite)
1 ¼ Tbs SRP
3/4 Tbs (or 2.25 tsp) Gypsum
Scant 1/2 Tbs (or 1.25 tsp) Azomite
This makes a tiny more than 1/4 cup.
Substitutes or additions…
⌘ Soft rock phosphate (SRP) (CalPhos) is directly linked to raising Brix. It is an easily assimilated rock-type product. It is becoming harder to find SRP, usually it is sold at places with amendments for farms or at places that specialize in natural growing products. It can be found online as well. SRP actually is an incredible ingredient and is very high in calcium and other trace minerals, in fact, the level of calcium is much higher than the available phosphorus. The phosphorus is very slowly released at low levels, with only 3% being available immediately, so it should be considered more of a calcium product than a phosphorus one. It will also stick in your potting mix and not water out, making it long-lasting. So if you can find it, get it, there is no product quite like it!
Otherwise, fish bone meal or crab meal can stand in as a different type of substitute for the SRP. Note that fish bone meal and crab meal both contain a certain amount of magnesium and nitrogen as well. They are not rock materials, so perhaps try to include other rock-type products, such as basalt, if using these. With these natural phosphorus containing ingredients, you should not need to add any other phosphorus product for your fig trees, especially if using fish amino acids. So, strike out the P in N-P-K, it is well covered with these!
⌘ Oyster shell flour can be a substitute for the high-calcium limestone. Anything that is 90% or greater of calcium carbonate can be used as a substitute for the limestone. I have heard of people using landscape chalk as a cheaper alternative since some products are 100% calcium carbonate. I’m not sure I would recommend that personally, definitely not if colored, but it’s something to consider if it’s the only available option. Another product is aragonite which is a calcium sand and Home Depot sells it at the time of this writing by a brand called Calcean. Finely ground eggshells can also be used, but they do take a long time to break down.
⌘ Basalt is another great one that has a ton of trace minerals. It can stand in for the Azomite or be added separately in its own right. Other volcanic or glacial rock dusts can also be used as a substitute.
⌘ Boron is one trace mineral that is important to Brix and to proper calcium usage. You can add just of pinch of 20 Mule Team borax to your pots, mix it in well at the time of adding calcium to avoid any toxicity. Because this is such a small amount, it needs to be added to each pot individually, otherwise there is no guarantee each plant will get it.
The minerals we left out…
A calcium deficiency locks out cations, which are minerals. High Brix requires proper mineral availability, so calcium is paramount. — Gee64/420Magazine
Mineral availability is linked to magnetism and electricity. Each mineral has its own magnetic pull and strength of charge. Some have more pull than others and can lock onto different minerals blocking them from the plant.
You’ll notice we avoided Epsom salts in our mineral mix above. If magnesium is too high in relationship to calcium, it acts up and binds onto everything making things tight. It does this with nitrogen, it magnetically bonds to it and locks it out from the plant. Calcium is stronger than magnesium in charge and helps to break that bond. When calcium is high enough, it frees up nitrogen and plants green up. Having higher calcium to magnesium also breaks bonds to give the soil greater porosity which allows for more air to be in the soil. This is essential for soil health so the aerobic microbes can breathe. Excess magnesium lowers Brix, so it is something we want to control the application of which is why Epsom salts are not included. Magnesium is also more widely available than some think through water and potting mix ingredients. It is essential, but is only needed in small amounts.
Potassium is usually added through other inputs such as kelp meal or seaweed extract. Molasses is another great one for potassium and trace minerals. Because these items are technically perishable, they are added when needed. Langbeinite, also known as Sul-Po-Mag, is a mineral input that has potassium, sulfur, and magnesium. It is a great input as well, but again, we want to control the release of these minerals, so it too is added as needed. (Note that it is higher in sulfur, so it is better not to use it when gypsum is going strong, as it also has a higher level of sulfur.)
Another thing about potassium is that too much of it can block calcium uptake from the roots. Calcium is best mobilized to a plant through its root system. I want calcium to be about 3 to 4 times higher than potassium in my fig trees. Figs love potassium, but they love calcium more. Potassium can, in effect, replace calcium to form cells. However, the cells are then softer, more rubbery, and weaker. Too much potassium can also cause a plant to burn through its sugars, thereby lowering Brix. High Brix soil is very high in calcium, but pretty low in potassium. There is reportedly greater microbial action and nutrient density in soils with higher levels of calcium, which is one reason for the higher Brix.
Potassium has great mobility through foliar sprays. Because of this, we may wish to favor foliar spraying when using products higher in potassium, such as kelp or molasses, or at the least, not over apply them to the soil. This also tells us to keep compost levels in check because it often is quite high in potassium. A little is good, too much can have a detrimental effect on calcium uptake. So keep an eye out to avoid large amounts of these ingredients when choosing a potting mix.
Calcium is the electrical current in our mix to elicit life and growth. None of the other cations work well if calcium is off. So all of the others do play their role but in lesser amounts which is why they are not here in this mix. This is especially so since potting mixes are often already high in them.
Making everything plant available…
Any dry minerals like these really need microbes to make them plant available. So adding any one of the ferments we’ve mentioned in this newsletter, such as FPJ or JLF, EM-1 which you can purchase on various sites, JADAM microbial solution (JMS), Lactic Acid Bacterial Serum (LABS), or a mycorrhizal product is an awesome idea to set your plant up for success. Mycorrhizal fungi is especially important to trees for nutrient uptake, so definitely consider adding it. It can take a couple of weeks for the microbes to kick in with the minerals, so you may want to premix everything, let it hang out for a week or two, and then use it for your plants.
Also, remember that amino acids can increase the uptake of minerals. So using a fish hydrolysate product or fish amino acids throughout the growing season can be very beneficial.
Fulvic or humic acids also can help to make minerals plant available. It is a good idea to use fulvic acid when using high-calcium limestone. Peat based mixes already will contain a certain amount of humic substances such as fulvic acid. We can also add some as an amendment if we feel a need for it or if using something without peat.
Calcium can be very mobile in water and rinses out easily because it is a heavy mineral— it wants to go down. So this isn't a product to put in the bottom of your hole at just the root zone area. That is too low and the calcium will only go down further with each watering until it goes out the pot drainage holes. Mix it throughout the potting mix and then top dress with it as needed. Mix it in enough so that it doesn’t clump.
This can also be added to rooting mixes to give our cuttings the best start possible. So don't forget that application as well! It does contain a certain amount of phosphorus which helps with root growth. (If you have a cutting that did not root and you don’t want the minerals to go to waste, you can use that mix on your other plants.)
And there you go… now you have a mineralized mix to get you started on the path to high-Brix growing! I can hear the satisfied sighs all around, including from me. 😜
I hope this gives you an easy way to increase your plants' mineral intake! Here is to strong, healthy plants for everyone!
As usual, excellent info... Thank you.