Yo DGC,
I recently had a magnesium and calcium deficiency in my veg plants. Using RO water and feeding with Dyna-Gro Foliage Pro, Silica, and Recharge.
I first noticed a magnesium deficiency by identifying yellow stripes on the leaves. I began adding 1 tsp epsom salt (magnesium sulfate) per gallon of water. I saw the plants begin to fix themselves over the next few days. Then I noticed the brown spotting that indicates a calcium deficiency – so I added gypsum (calcium sulfate) at the rate of 0.5 tsp per gallon. At this point I dialed back the epsom salt to 0.25 tsp per gallon.
The plants seem to be fine now besides a bit of nitrogen toxicity. Which is a bummer because I thought the super dark leaves looked awesome – but then I see the “claws”.
I’m using rockwool croutons, and the plants are responding astoundingly well.
So my question is: Can I use only epsom salt and gypsum as my cal/mag supplement and forget about the expensive bottled versions?
Thank you!
Pretty sure that someone recently mentioned about manganese acting as a sort of mediator in the event of lockout due to calcium/magnesium antagonism when there’san excess of both… Was that guru maybe?
Maybe it’s not such a bad idea, so long as it doesn’t create an abnormally high sulfur ratio.
I’m anxious to hear what dude/Scotty/guru have to say. I love good ideas for cost effective resourcefulness
That would be awesome if dude, Scotty, and guru could give their thoughts. I’ve almost completely cut out my calmag supplement and i don’t see anything wrong with my plants – so I’m pretty confident it works. But a are we getting something special in calmag supplements? I was reading online that bottled nutrients are using epsom salt for magnesium. I’m also reading that calcium nitrate is the best source of calcium for plants, hence lots of calmag supplements also contain nitrogen. If i actually find scientific information then I’ll make a post in the nutrient guide about it.
If you are looking for simplicity, its probably easier to ditch the RO filter and just use the minerals in your tap water as a source of cal mag. There also might be other kinds of water filtration you could use that dont pull as much cal mag out but still remove whatever nasty stuff you are concerned about.
Get a water report (free from the water company) and find out whats really in your water before you go crazy filtering stuff out. Find out if there is anything you actually need to filter out, and get the best filter for that specific situation.
This might be controversial, but I suspect 99.9% of growers dont need to be using an RO filter. In most cases, most of the PPM in your tap water is minerals like cal mag your plants can use. When you use RO water, you are stripping free cal mag out of your water and then buying additional cal mag products just to put it back in again.
I dunno what your water is like but unless its truly awful or full of toxic crap you probably dont need to be using an RO filter and could get by with either a less restrictive filter or none at all. In most cases the main thing it is filtering out is minerals like calcium and magnesium, and then you end up buying bottles of cal mag to introduce those same things back in. So it ends up costing you money to filter it out, and then you pay again to add it back in.
As far as gypsum and epsom salt go, I would be very careful using them with your setup.
When working with soil at least, the ratio of calcium to magnesium is very important. So if you are making your own CalMag type product, its probably pretty important you get that ratio right.
Epsom salt is MgSO4, so it has a lot of magnesium and sulfur in it, but no calcium.
Gypsum is CaSO4, so it has calcium and sulfur in it but no, magnesium.
I have no idea how the two might interact or become more/less available when they are combined. You also might throw things out of balance by adding that much sulfur into the equation…
I dunno… It might be better to rely on the stuff made by the experts.
the Cal MAg in Well water is usually to large because its untreated so it will lock out Cal Mag in Plants with well water like mine.. What works is a simple water softer with Potassium . Then add Cal Mag as directed ..
Soup… That’s fucking excellent insight!
I have well water that’s rather fortified with minerals.
Its gross to drink, so I use a zero filter, but it’s working pretty well with my rhizosphere unfiltered.
Absolutely get a water analysis, and you are probably robbing your water of the good stuff by RO treatment.
Brita filter? If you really need it.
Thanks for commenting guys i really appreciate it. I’m actually in a situation where it’s not an option to use the water as is. Would be really nice if i had good water to start out with.
I calculated the mineral additions so that i get 25 ppm magnesium and about 120 ppm calcium from the 1/4 tsp per gallon epsom salt and 1/2 tsp gypsum per gallon. Soup i think it’s about the 5:1 ratio of calcium to magnesium i always see people saying online.
I do wonder what all the sulfur is doing in there! I should check if there are any peer reviewed research on that. As far as trusting the expert nutrient makers – I think the DGC are the real experts. I trust you guys way more than companies.
Greetings beast_in_the_east. Back in the early 1900’s, before we knew about bioavailability, scientists thought a 5:4 cal/mag ratio was a good idea. We know better now and a 5:1 or 4:1 ratio of calcium to magnesium is fine for most hydro and soil plants. Sulfur is sometimes considered the fourth macro element so don’t wonder why it’s used in abundance like npk. Sulfur helps make up amino acids, proteins and chlorophyll. Sulfur levels gotta be high enough but not too high for plants to utilize available nitrogen also.
Excellent to know about sulfur and the ratio Mystro. I was listening to an episode of DGS and Scotty mentioned that he never experienced any problems by adding extra calmag.
I hate telling my friends they are wrong, but when it comes to mineral nutrition, often times they are. No such thing as good “extra” minerals like calcium. Mineral ratios are the most misunderstood part of growing. It’s the difference between popcorn buds and monster colas. It’s the part of growing my father taught me first. Calcium has a fairly strong positive electrical charge compared to other elements with positive charges. The element with a negative charge calcium tends to antagonize the most is phosphorus because of it’s abundance during flowering. Too much calcium is a very bad idea unless you like popcorn buds. Purpling leaf stems is the first sign P is getting locked out. Leaves won’t grow big either. Healthy plants can grow leaves the size of my hand in the first few days. A plant with too much calcium will grow leaves with purple stems and will stay small and stunted. The problem isn’t always glaringly obvious to even experienced growers.
Dude my plants are showing purple leaf stems as soon as temps hit low 60’s overnight. That crazy you posted that because I saw it just a few days ago in my plants. I did suspect P deficiency, but was hoping it was just a characteristic of my plants.
I like the attitude of not just accepting any standard methods and really getting into the science. This is a cool topic that I want to get real science on. Next time I get a free day or two I’m going to do some digging around the net for good data.
Purpling from cold or genetics can look very similar to lockout purpling in 70-80 F temps. That’s why it’s impossible to diagnose issues with just a pic.