# Magnesium deficiency? Epsom salt to cure? **URL:** \ **Category:** Troubleshooting\ **Tags:** flowering, lighting, autoflower, indoor-grow\ **Created:** [August 17, 2025, 12:53am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044 "2025-08-17T00:53:54Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![retroking87](https://avatars.discourse-cdn.com/v4/letter/r/a5b964/32.png) [@retroking87](https://ilgmforum.com/u/retroking87)\ **Post date:** [August 17, 2025, 12:53am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/1 "2025-08-17T00:53:54Z")
I’ve been up and down the forums, and I think I have a magnesium deficiency. Yellowing between the veins. I read that rosin salt can help. Even that foliar feeding this is effective ![IMG_0810](https://global.discourse-cdn.com/growingmarijuana/original/4X/9/8/2/9820a6f14955f14ea27ae0f9125bb9c863b9b10a.jpeg) ![IMG_0805](https://global.discourse-cdn.com/growingmarijuana/original/4X/1/b/0/1b0034d5d634ae6608aa4bd08fe27bc91808aa0b.jpeg) ![IMG_0806](https://global.discourse-cdn.com/growingmarijuana/original/4X/6/d/a/6dacdd22143e06a3128e278d770609241df27b58.jpeg) ![IMG_0804](https://global.discourse-cdn.com/growingmarijuana/original/4X/c/1/f/c1f56713cc39990b29807ae9ccf5f3eb854d5e69.jpeg) . 2nd week of flower from what I can tell. I feed cal mag every watering. Since they are stretching watering has increased to every other day. Fully switched over to maxibloom per package instructions. Ocean farms is the medium. Dechlorinated tap water ph to 5.8-6.2. First hiccup In an otherwise smooth grow. First time with autoflowers and indoors. Any help would be appreciated. ---
**Author:** ![Borderryan22](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/borderryan22/32/1167090_2.png) [@Borderryan22](https://ilgmforum.com/u/Borderryan22)\ **Post date:** [August 17, 2025, 1:01am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/2 "2025-08-17T01:01:27Z")
> [@retroking87](#): > > 5.8-6.2 Soil needs a slightly higher pH. Bump up closer to 6.3-.5. ---
**Author:** ![Borderryan22](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/borderryan22/32/1167090_2.png) [@Borderryan22](https://ilgmforum.com/u/Borderryan22)\ **Post date:** [August 17, 2025, 1:02am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/3 "2025-08-17T01:02:36Z")
Oh hey, welcome aboard also! ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 1:18am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/4 "2025-08-17T01:18:30Z")
> [@Borderryan22](#): > > Soil needs a slightly higher pH. Why? Like why would it need to be higher in soil ---
**Author:** ![Fritzy](https://avatars.discourse-cdn.com/v4/letter/f/dbc845/32.png) [@Fritzy](https://ilgmforum.com/u/Fritzy)\ **Post date:** [August 17, 2025, 2:08am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/5 "2025-08-17T02:08:26Z")
There are some charts out there I don’t have it sorry. But it shows that PH of 6.5 in soil is where the plant can take in all the nutrients it needs. If you go too far above or too far below that 6.5, it will not allow the plant to take up certain nutrients. Then will show a deficiency. ---
**Author:** ![Borderryan22](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/borderryan22/32/1167090_2.png) [@Borderryan22](https://ilgmforum.com/u/Borderryan22)\ **Post date:** [August 17, 2025, 2:43am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/6 "2025-08-17T02:43:26Z")
I’m not sure the science behind it exactly. Coco/hydro pH 5.8-6.2, soil 6.2-6.8. Organic/living soil pH doesn’t need to be specific, but usually between 6-7.5. I know that much, but not reasons for the pH differences. ---
**Author:** ![Deadhead](https://avatars.discourse-cdn.com/v4/letter/d/e9c0ed/32.png) [@Deadhead](https://ilgmforum.com/u/Deadhead)\ **Post date:** [August 17, 2025, 2:47am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/7 "2025-08-17T02:47:34Z")
5.5-6.5 is a nominal range, although I’ve seen one source suggest 5.8-6.1. ---
**Author:** ![SausageMahoney](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/sausagemahoney/32/1075204_2.png) [@SausageMahoney](https://ilgmforum.com/u/SausageMahoney)\ **Post date:** [August 17, 2025, 3:00am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/8 "2025-08-17T03:00:21Z")
pH is the ability of your soil to allow the uptake of most nutrients. The lower the pH, the more hydrogen in the soil or more acidic. It also has an effect on microorganisms and their ability to do what they do. Usually if I start having issues, pH is first check. Recalibrate meters and check runoff. ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 3:09am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/9 "2025-08-17T03:09:12Z")
I knew that i was just wondering why it’d be different for soil and it’s because the soil buffers it so you put in 6.5 but it buffers down to like 6.2 or so. I didn’t know but i googled it ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 3:11am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/10 "2025-08-17T03:11:51Z")
That’s what I’ve seen and i do rdwc. I like to keep mine Anywhere from 5.8 to 6.2 but anything from 5.5 to 6.5 is okay and the reason soil is higher is cause it buffers it so you put in a little high and it’ll and up right ---
**Author:** ![Fritzy](https://avatars.discourse-cdn.com/v4/letter/f/dbc845/32.png) [@Fritzy](https://ilgmforum.com/u/Fritzy)\ **Post date:** [August 17, 2025, 3:12am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/11 "2025-08-17T03:12:34Z")
I think @MidwestGuy put the chart that will better explain it or @OGIncognito or @Myfriendis410 @Growdoc they might be give a more detailed information than i can. Good luck ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 3:12am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/12 "2025-08-17T03:12:56Z")
That’s why i was wondering cause i figured whatever you grow in it should need the same ph ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 3:13am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/13 "2025-08-17T03:13:43Z")
I know about the ph and what it gets from what ph i was just wondering the difference in soil vs say like rdwc ---
**Author:** ![Fritzy](https://avatars.discourse-cdn.com/v4/letter/f/dbc845/32.png) [@Fritzy](https://ilgmforum.com/u/Fritzy)\ **Post date:** [August 17, 2025, 3:13am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/14 "2025-08-17T03:13:46Z")
Im more of a coco guy so 5.8 is my number ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 3:17am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/15 "2025-08-17T03:17:07Z")
That’s my goto for budding but for veg i like it up to 6.2 ---
**Author:** ![Deadhead](https://avatars.discourse-cdn.com/v4/letter/d/e9c0ed/32.png) [@Deadhead](https://ilgmforum.com/u/Deadhead)\ **Post date:** [August 17, 2025, 3:48am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/16 "2025-08-17T03:48:55Z")
I never bothered with pH during virtually all of my soil grows, and when I did start checking recently, it was always okay. During half a dozen years of growing indoors in dirt, I ignored pH and never had a plant go tits-up. I did a lot of things the “wrong” way in those grows and got a decent amount of potent dope as a result. Now that I’m growing DWC, I know I have to check and pH down my water from 7.4 to 5.8. With Jack’s 321, it gradually crawls up to 6.5 after two weeks, and I dump and resupply. ---
**Author:** ![Stoner4202](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/stoner4202/32/1144882_2.png) [@Stoner4202](https://ilgmforum.com/u/Stoner4202)\ **Post date:** [August 17, 2025, 4:05am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/17 "2025-08-17T04:05:28Z")
Same lol i did maybe like 5 grows in soil then switched to rdwc and never looked back lol. I never checked any numbers in my soil grows but they grew fine so whatever. i prefer RDWC though cause of how easy it is. Like say i wanna know how much water they have or check my ph or ppm i can just look and it only takes a minute ---
**Author:** ![Storm](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/storm/32/1066086_2.png) [@Storm](https://ilgmforum.com/u/Storm)\ **Post date:** [August 17, 2025, 6:22am UTC](https://ilgmforum.com/t/magnesium-deficiency-epsom-salt-to-cure/120044/18 "2025-08-17T06:22:37Z")
Welcome aboard. Some pictures in white light will allow a better look at leaf discoloration and help a prognosis. The blurple distorts what we are trying to see. If thinking mag just add a tblsp epsom top dressed in and see. Wont hurt it. Can only help. Take a week to see new growth green. Damaged leaves wont fully recover typically. Just my thoughts.