Northern Lights Fem Auto. Sick Plants! need help

so like the title says i have some sick northern lights fem auto plants. there around 3 and a half weeks from sprout. under a 400watt mh. growing in promix bx soiless medium and getting fed with a 15-5-5 with micro nutrients.


heres some pics





the next pic shows that the one plant has had problems since sprouting



next pic the plants is just starting to have the problem the last day or two


and last pic is of the only healthy plant. my phone and he lights make the top look pale but its not



so the one plant has had brown spots since it was little then about 10 days ago another got brown spots. since the plants hadnt been fed yet i gave them a 1/4 strength feeding. then a few days after that the third plant got brown spots. now 3 days ago i gave them a feeding that was a bit stronger then half strength. anyways if anyone can indentify whats going on here would be good. thanks in advance. need to get these babys healthy before they start to flower.

Ph is off.
Autos are nutrient sensitive. If you must feed, go with 1/8 strength. Increase it very gradually based on growth achieved from previous feeding.

Flush them out with 6.5 pH plain water (w/calmag (if using ro).
Let them be for a week and give 1/8 strength.

2EyedCyclops said:

growing in promix bx soiless medium and getting fed with a 15-5-5 with micro nutrients.

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Are you ph'ing your nutrients? I grew in Pro-Mix HP and it likes 5.8-6.0 in veg, 6.0-6.2 in flower.

I've since added soil to my Pro-Mix (20% Kellogg Patio Plus, 20% Perlite, 60% Pro-Mix) and treat it like soil. I don't even ph anymore. But, without the buffers of soil, I think you should be sure you're in that range.

Did you add dolomite? I added 1tbsp/gal when I grew Pro-Mix by itself.

What brand food are you using?

It's straight promix. I haven't ph'd the soil run off or the nute mix, I'm going to go get some test strips in the morning. Im using miracle grow brand nutes. It's 15 5 5 and seams to have all the micro nutes except calcium. I've been looking for a calcium supliment but haven't found anything. And save the hate lol I ordered a set of fox farm nutes from Amazon. Should have been here already so any day now.

I will ph the soil as soon as I can. Can't tomorrow because I don't want to over water them.

2EyedCyclops said:

save the hate

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I'm growing in MiracleGro Tomato right now. It's going well. (I can't think of an MG product that's 15-5-5. Which one did you get?).

The Ca should come from your water and dolomite. Gypsum has calcium, as does dissolved eggshell. But, you should't add stuff like that without a reason (you can cause lockouts by gratuitously adding things like that.).

Test strips may not work well for you if the nutrient solution is colored. You can get a eTeckCity pH pen on Amazon for about $25. Depending on who you buy from, it may come with a foil packet of calibration solution (mix it with distilled water). Pens are a maintenance headache though (storage and probe cleaning solutions).

You're actually not in soil, it's soilless. That's a distinction you may want to emphasize. I'm not sure how FF nutrients work in soilless. I used hydro nutes in soilless.

What kind of water do you use? If tap, what is your TDS?

How much time did you spend studying how to grow before planting a seed?

I've been growing weed for more then 10 years. A dozen plants every summer All outdoors all organic and never had a problem. ive also done 2 indoor. both times were single plants under 2 big cfl grow lights. Done in soil. Also never had a problem with those grows either. The miracle grow is orchid mix. Not really designed for weed but should be fine. I would be using something else but the local garden stores don't have a lot of stock in December. The fox farm I ordered is there hydro formula so it should work. I don't think the problem has anything to do with my nutes though. Mainly because the problem started before they got their first feeding. I'm thinking more then likely the "soil" ph is off. I'm going to try and use the strips, there cheap and I can buy them at a store. O and I'm using just tap water. It sitts in a jug overnight to get to room temp before I use it. I used bottled water for germ and until the plants had there first set of actual leafs. The plants are also in 5 gallon buckets and have been from seed

2EyedCyclops said:

The miracle grow is orchid mix.

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I think that's your problem. I believe orchid food is more acidic.

2EyedCyclops said:

I'm using just tap water.

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What is the TDS? It's probably not the problem, but would be handy to know if/when additional problems arise.

2EyedCyclops said:

I'm thinking more then likely the "soil" ph is off.

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It's possible you got a bad bag of Pro-Mix. Every bag I've used was 6.0-6.2 out of the bag. I add some soil to mine and make it soil, not soilless. It becomes 6.4'ish.

Is it possible you're watering too frequently, not letting the medium dry? Do you wait for the container to feel very light? You're not topping it off every day to keep it wet like a houseplant, are you?

Not sure what tds is? I've watered the plants 4 times in the last 3.5 weeks, I've let the "soil" get really dry before watering. Ya the nutes def arnt the best for weed but I still don't think it could cause this because the one plant started getting brown spots when it was still on bottled water with no feed in it. And ya it might be possible the pro mix was a bad batch. I purchased it at the end of December and it had prob been sitting outside side at the garden store since at least last spring. But ya I'm going to use the test strips tomorrow to at least get an idea what it's at. I will test the unused soil because I won't be able to water the plants tomorrow and I will test the water with the nutes in it. thanks for the help. This is a learning experience for me. Having a good time with it but it's hard to beat the feeling of a warm greenhouse under the sun.

2EyedCyclops said:

Not sure what tds is? ... I still don't think it could cause this because the one plant started getting brown spots when it was still on bottled water with no feed in it.

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Total dissolved solids. You should find out what it is. Often it's too high and interferes with the nutrients which are also TDS. You can buy a meter on Amazon for $20, or check with your water provider.

The brown spots were calcium deficiency due to the bottled water having all the Ca filtered out. That's kind of common. I mix filtered and tap water to get an initial 150ppm. If I didn't I might get deficiencies too. Dolomite amended into the medium before planting can help. Pro-Mix has some, but I always added 1tbsp/gal.

I think your problem is the fertilizer.

Ya I might need to get one of those meters. The water for my house is fairly hard so it goes through this big filter thing that's the size of a hot water tank that gets filled with some sort of salt.

2EyedCyclops said:

Ya I might need to get one of those meters. The water for my house is fairly hard so it goes through this big filter thing that's the size of a hot water tank that gets filled with some sort of salt.

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You don't want to use softened water. That contains sodium. Your pre-softened tap water should be good to use, but you'll want to dilute it down to 150ppm with RO water. (That's a good way to avoid the cult of calmag, using RO water by itself -- then adding "calmag" to make water more like water.). You'll need a ppm meter or call your water provider who should be able to tell you the avg TDS through the year. You can use that average to get close to 150.

I would do 50/50 pre-softened tap and RO until I had that info. I might feed next time with 50-100% runoff.