I have 12 plants, 2 weeks old. They are in 1 gallon pots. The bottom half is 1/2 Edna’s best potting soil and Subcool super soil. Top half is Edna’s best potting soil, a local organic potting mix.
The plants are starting to display this symptom. This is the most dramatic plant, but they all have this coloration.
What nutes and strength are you using?
To me it’s a typical mag issue look though
Agreed. Try some epsom salt.
1 tsp/gal sir and all will be righted in a couple days
I would like to add that a foliar feeding of magnesium sulfate might be another option. I use 1tsp/gal and spray once every two days just before lights out for about a week.
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I’m trying to learn as much as I can about nutrient deficiencies and such. The more I think I understand, the wronger I turn out to be. But…isn’t magnesium mobile? Meaning that it would be showing signs on the older leaves first? The typical interveinal chlorosis of magnesium deficiency is there, but I’m confused since it’s showing up on the new leaves first. And also because the plants are only 2 weeks old.
???
Here’s a tidbit on Magnesium you might find helpful
Magnesium (Mg)
Magnesium is dissolved in water as magnesium cation (Mg2+) and is absorbed by the plants in this form.
This metal plays a decisive role in photosynthesis. Magnesium is the central atom of the chlorophyll molecule, very much like the iron atom in the rather similarly structured haemoglobine (red bood pigment). Magnesium also fulfills many other functions in the organism of plants, e.g. in the activation of enzymes, the formation of proteins, DNA and RNA, carbohydrates, fats and vitamins, in phospate transportation, the carbohydrate metabolism and the transmission of energy. Inside a plant, magnesium is most highly concentrated in the areas where the plant grows. Calcium, though chemically rather similar, is most highly concentrated in the oldest parts of a plant. Magnesium is relatively mobile within plants.
The symptoms of a magnesium deficiency can look similar to those of iron deficiency, e.g. the leaf tissue pales between the leaf veins, which remain green. However, a chlorosis caused by an iron deficiency first shows in the youngest leaves, and a lack of magnesium usually first affects the older leaves.
An aquarium plant may not need much magnesium, however, even that small amount is often neglected. Not much is known about the effects of magnesium in specific plant species at low or high carbonate hardness levels, or how high the magnesium concentration may rise without toxic side effects. On the other hand, plant problems are often attributed to magnesium, calcium or potassium deficiencies, however, one should always make sure if the nitrate and CO2 levels of the water are sufficient first.
Together with calcium and other alkaline earth metals, Mg2+ contributes to the total hardness of the water. Many naturals waterbodies contain far more magnesium than required by the plants. Quite often, tap water also contains certain amounts of magnesium, and regular water changes suffice for providing the plants with it. However, sometimes almost all the total hardness is formed by calcium ions, and then the plants might suffer from a lack of magnesium even though the GH is over 5°. In literature, the “ideal” calcium-magnesium ratio for plants is often given as 3:1 to 4:1.
If you suspect a magnesium deficiency in your plants, add a small amount of magnesium sulfate (MgSO4·7H2O), e.g. a quarter teaspoon per week. A positive effect on the plants should be visible within a week or so.
The following Aqua Rebell fertilizers add magnesium
So my take on this is that it’s can show up on both upper and bottom growth which makes it a difficult one to diagnose at times!
I totally agree that it’s difficult to diagnose. Pretty much everything that can go wrong with a plant is difficult for me to diagnose, especially from just a picture.
With iron deficiency and magnesium deficiency both having similar interveinal necrosis, what’s the best way to determine which is which? And does pH and EC have anything to do with anything?
Zinc deficiencies look blotchy. Magnesium is fairly uniform spreading outward and leaves generally curl slighty upward. They call it “praying for Magnesium”.
The best thing would probably just treat for both IMO in small doses at first and observe … but yes ph is very important high or low can cause lockout of certain minerals and excessive nutrients of certain ones can lock out others as well you can see how it can start to get very confusing @McMuffin at times I believe temps can play a part as well IIRC then you can also have strains that just plain picky as well. If your a first time grower soil will be a lot more forgiving IMO.
I’ve always thought that the first step of troubleshooting a plant problem would be soil analysis, starting with measuring pH.
Agreed, it does get very complicated when considering all the variables that can cause a plant to have problems.
Slurry test shows 6.5pH
Sounds good. Just try an Epsom foliar then litfa
The plants got a nice big drink of epsom salt water. A couple days later, they are starting to look worse.
I’m going to try to give them a quick spritz before I leave the house until Wednesday night.
Plants have been spritzed. I won’t have another chance to look at them until Thursday, so I am keeping my fingers crossed.
Foliar feeding is so much easier than spraying for pests 
My heartfelt thanks to everyone that helped.
I just got back from the coast, and the plants look great!
So happy
Should I continue to add epsom salt to the water?
I would say start with every 2 weeks. If they want more then give weekly
So, the symptoms went away with a foliar feed, but now they are back and worse than ever.
I have been feeding them with epsom salt in the water, and did back to back foliar feeds yesterday and the day before.
Is there something going on beyond the magnesium deficiency?
pH reads 6.5, but that result is from a slurry test using low TDS water, not distilled.
The soil is Subcool’s recipe, as seen here:
https://www.google.com/amp/s/hightimes.com/grow/subcools-super-soil-step-by-step/amp/<img
The soil got very wet and was muddy all winter.
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Thanks for any help!
