Need Advice - Thinking Calcium Deficiency

Need some advice.

This is first indoor grow that I’m “Serious” about. Grew indoors last winter but didn’t pay much attention to plants and it showed.

Trying to determine if this is a Calcium deficiency or something else.

Purple Kush & Northern Lights Photos
15 gallon container
Happy Frog Soil
PH is right at 7
2 315 watt CMH running at 75 percent
Temperature 77 - 80 during day, 70 - 75 night
Humidity about 40 percent
Seeds were purchased here

Started these ladies in solo cups and repotted at 2 weeks.
Currently coming up on 5 weeks
Didn’t give any nutes until 2 weeks ago
Tablespoon of Roots Organic twice (one at beginning week 4 and one beginning week 5)

New leaves have yellow tips and older leaves have brown spots starting

From research I’m thinking Calcium deficiency.

Saw picture that also look like Boron deficiency but read that is pretty rare.

Thanks in advance for any advice.


Do you have bugs? Whats on the underside of those leafs? Got a microscope?

Just looked with a jewelers loop and see no bugs or evidence of bugs.

Also, forgot to add these are in 5x5 tent with an 8 inch exhaust through a carbon filter.


as far as cal-mag goes- I use it every time I feed. Add it to your schedule if you don’t use it already. But I don’t think that is your issue. The burn spots makes me think bugs.

Any recommendation on a product to use for bugs - good preventative measure even if its not my issue.

I use some hard stuff. From Flying Skull. Nuk’em. Real good stuff. I use very small amounts in a small pressure sprayer. Follow directions closely. Do at lights out. Their clone guard is also the bomb- if you don’t use it already. Keep it in stock and its there if you need it.

Thanks for the info. Will treat for bugs and cross my fingers!

Will also start giving cal-mag with every feed.

Best luck. Buzz me if u need help.

What is your runoff PH and PPM’s? Asking because HF is fairly hot soil, and lots of folks put an arbitrary time frame, say 4 -5 weeks, and then start feeding. Your PH you say is 7.0? Is this your watering or runoff? I grew twice in HF and OF, and it was a good while before I had to feed. I go by the runoff numbers to tell me if she’s hungry. A PH of 7.0 is a little high for growing in soil. The sweet spot appears to be around 6.5 or so. I am growing in Coco now and using Jack’s 3-2-1 nutes, and so far it is working out great.

Hey @jetlag. That is the water PH. I just had water in my house tested so that’s how I know. Looking now to order tester so I can test runoff PH and PPMs.

That will hopefully help with the feedings. Thanks for the info on the Coco and Jacks. See how this grow goes and decide on the next.

You are welcome, just for information sake, Bluelab and Apera are two well regarded names here. I use Apera, and they have a couple of models that will test both PH and PPM’s on the same device. You will be amazed at what you read going in and coming out.

@jetlag testing the PH and PPM and need some advice/help. PH going in a bit high at 7.5 but runoff is between 6.3-6.5. I cannot get PPM down. I’m using RO and PPM in is under 15. Out has been going UP and UP. It was about 1600 but now up over 2000 on 3 of the and just under on 1. Have been flushing every other day with 1/2 to 3/4 gallon each. They don’t seem overly stressed - just a little yellow tips. The 2 bigger plants, One Northern Lights and one Purple Kush (photos) are 6 weeks and were fed twice before I started testing. Haven’t been fed for over a week. The 2 smaller ones just over a week old are Amnesia Haze Auto’s. They are in FF HF which I understand can run hot but how can I get these numbers down? Or do I care because they aren’t burning?

There is an old saying, if it ain’t broke, don’t fix it lol. Your runoff PH is in the sweet spot, so no issues with that. Is there a reason why you are giving them 7.5PH water? I have grown in HF and OF together and they are a bit hot, but they are a good grow medium. I had, still have 3 White Widow plants outside in a 50/50 mixture of HF/OF that I have done my best to try to kill over the summer, and still hanging in there, not pretty but still there. I had a major lockout, but heat was a major factor there, and was going between too much feed or none at all. The yellow tips could be nute burn? They look good and they may just need a little water once you let them dry. I am not sure the flushing is a good idea at this point and certainly not the little ones. HF will keep them content for a while. I never fed mine for over 6 weeks and they were happy. Over watering can bring on its own issues. I would let them dry out first, then water well, The little ones are certainly more susceptible to overwatering, and you would see them droop and maybe turn yellowish. The numbers would be normal for HF and you say you have fed twice already. Mine were in the 3000 range with the OF mixed in. They look good, and I don’t think you have a lockout issue. All that watering may be releasing more nutes from the soil and increasing your numbers. By the way, flushing entails running water 3-5 times the size of your pots. I have been recently swayed by some with much more knowledge than I here, ILGM Moderatos and staff Engineers, who have switched to growing in Coco Coir and in my second small grow with it. I also switched to Jack’s 3-2-1 nutrient formula. Totally different animal. It might be worth a read. Enclosing a link to my two girls, Girl Scout Cookies Extreme.

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Forgot to add the link, lol.

This is all great information. I thought the PPM run off was high. Had read about 1000 for Veg in 5-6th week. I have a lot to learn still on how to interpret the numbers and know what they should be! Most of my grows have been outdoors over summer and straight into the ground in corner of veggie garden so I didn’t pay any attention to numbers. The PH is 7.5 going in because I have RO machine in the house and that’s how it’s coming out. I didn’t’ want to mix anything with it when trying to lower the numbers on my run off. I’ll try getting it down a bit for future watering’s

All good reading and definitely looking at the Coco Coir and Jack’s for next grow.

Thanks Again.

My pleasure, and I forgot about the RO water, so you are good. I am using RO as well since our tap runs between 5-700. All those numbers are guidelines as well, if plant happy leave alone.

Update on plants. They are looking pretty good.

Topped, some defoliation and trained. Going to let them go another couple weeks and gain some height before I switch them over to flower.

The white on leaves isn’t WPM - My fat fingers spilled some cal-mag on watering can I didn’t notice until it was all over the ladies.

@Nicky @jetlag @forcedinduction @Covertgrower @Holmes

Leaves are turning a bit yellow. This is week 9 in FFHF. They were only fed once at week 4 until I was educated on reading PPM in runoff.

Since then runoff has dropped from high 2000 to about 1700. Still seem pretty high for week 9. New leaves were showing nute burn with yellow tips but now entire leaves are starting to turn yellow. Thinking it may be a nitrogen deficiency but concerned about feeding them with PPM so high. Watering with RO water and runoff is between 6.3 and 6.6. I have been giving CalMag with each watering (every few days) Want to flip to flow soon but want them healthy first!

Thanks for help.

Hmmm well ide start with a soil slurry sample to accurately check your PH and tds.
Let’s go from there.

In soil a high ppm like that should be fine if it’s organic but you fed soo…
Also it’s week 9 so that feed you gave in week 4 should be long gone.
Somethings not adding up here…
Take a slurry sample and let’s go from there you may have to flush and feed.

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