Nitrogen or potassium deficiency? [pics]

My grow:
5 plants growing indoors, in soil, under 4x 54w T5s.
Watered once bi-daily with Botanicare Pure Blend Pro Grow (vegetative food [3-1.5-4]) and Liquid Karma (all-the-time-food, I guess [.1-.1-.5]).
The pictures attached are current, 3.5 weeks since germination. Everything has been peaches and cream easy until this issue.

About half a week ago I noticed the bottom leaves of my plant were starting to turn yellow. I did a quick Google search and learned that it was most likely nitrogen deficiency. Well, my Pure Blend Pro Grow has almost all of the nitrogen my plants are recieving, so I assume I needed more of that. I went from 2 tbs./gal. to 4 tbs./gal. Today, while I was watering the plants for the first time with that mixture, I noticed that were spots on my leaves! Another Google search led to me to believe that it's a potassium issue, and that I need to buy some potassium booster from my local shop.

However, before I go and do this I was hoping to get the community's opinion on what they think the issue is. Attached are pictures of my plants focusing on the worst areas. Thank you for your input! First grow.

edit: I hope it's not an issue that I used imageshack.us. The integrated file uploader doesn't work for my browser

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I figured out how to upload correctly These are the only two worth viewing, the second one isn't on imageshack.

It does look like N deficiency but that can also be caused by the soil pH being off. The plant won't be able to use all nutrients when the soil is the wrong pH, so start by acquiring a way to test the soil's pH if you don't have one already. The cheapest soil tester is probably the capsule-type pH test kit (~$6) followed by an analog probe-type pH meter (~$8-15) and then a digital probe ($20+). Once you've checked the soil pH, mix up some fertilizer and set the pH (using test strips, a pH pen or other liquid pH tester) so that when it mixes with the soil, the combined pH equals 6.5.

While N may be the nutrient they are most deficient in, they're going to need a fertilizer mix containing some of every nutrient they use or you'll just end up with other deficiencies as soon as you fix the Nitrogen problem. The spots on the leaf in the first pic are probably from early Phosphorus deficiency.

So if I understand you correctly, this is my shopping list:

-Some form of pH testing
-Liquid pH modifier
-Fertilizer for the soil so it'll have nutrients that aren't included in the plant's food

For the pH testing and modifying, if I find my pH is off by quite a bit, will mixing the pH modifier material into the water that I feed the plants with be all I need to correct the issue? Or do I need to change out the soil somehow?

Thanks for your reply, I need all the advice I can get :O

Your plant is over watered. That is a deficiency, but throwing more food at it isn't necessarily the solution.

First, allow the soil to go practically dry before watering. When you lift the planter and it feels feather light you will then water to saturation.

Use a pH balanced solution, at 6.5 to 6.7. If you'd like to use nutrients your plant is old enough to with stand a 1/2 strength suggested feeding of a high nitrogen and calcium nute.

After your next watering (which might not be for a week judging by the look of the planter) allow a few days to pass. The soil should remain moist enough to hold itself together when clumped, but not so moist that it is muddy or heavy enough to fall apart in chunks. Remove the plant and soil from the planter and remove all the soil you can from around the root ball without damaging the roots. A little damage is unavoidable, but do what you can to limit that.

Transplant the remaining root ball into a high quality organic potting soil that contains at least 25% perlite mixed in. You will probably need to amend your soil to get enough perlite in it for indoor growing. A Tbsp. of crushed dolomite lime per gallon would be wise also.

Water again when it is feather light. It might take 6 days, it might take 3 days, but the key to watering is to NOT do it every day. Young plants require very little water and that media you are using to grow in, saturated the way it is, is suffocating your root system and impeding nutrient uptake. Concentrate on building healthy roots and let the soil and the plant take care of the rest.

You have some very good solutions here dude. After reading through, I agree with everyone above. Bouncing off Mother's Finest, it is important to ntoe that just because you show a deficiency in something it does not mean that the nutrient is lacking within your medium. It only means it is lacking in the plant. Therefore, the factors inhibiting nutrient uptake are: Nutrient Lockout, or Nutrient Deficiency.

Lockout typically occurs when your PH is off. Balance sat-out tap water(let sit in open air for 24 hours to rid chlorine) to 6.5 for nutrient uptake. Soil mediums should runoff to a ph of 6.5, but a 6.3-6.6 range is okay, though not precise. I would recommend buying some dolomite lime crystals or liquid(liquid has a more rapid intake) and top dress it into your soil. Lime will balance the soil to near 7.0 over the course of weeks and months. It is slow acting, and typically done to dress and miz a soil before propagation. However, you can amend it now with varying results. Either way, it wont hurt. 1 TBSP of dolomite per gallon of soil---precise measurements dont really matter though, long as its ballparked.

If you want some more clear cut answers, you really need to give us more ifnormation. IE, soil mix, water being used, how much watering being done, how often being watered, how often given nutes, etc etc. Then setup, lighting, etc details all help in giving us an idea on how we can better help you.

Thank you very much for your replies. It's nice to know no matter what problem occurs, chances are I'll be able to correct it with the help of a community like this.
Let me make clear my goals of this grow, I do not necessarily care about yield. As I'm just starting out, this is me dipping my feet into this field. I would like to triple or quadruple my crop by cloning these five when they are old enough.

As per request I have more information on my setup, as well as pictures and links to accompany.
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Firstly, my watering regimen consists of Botanicare Pure Blend Pro Grow and Botanicare Liquid Karma. I also have Botanicare Pure Blend Pro Bloom for later flowering stages. I use the amount prescribed on the back of the bottles for each stage of plant development. (Right now for example, early vegetation, calls for 7.5ml/2L of Pro Grow and 5ml/2L Liquid Karma.) I water every other day.
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I used a very basic soil because I thought all that mattered was that I keep my nutrients well managed. I specifically bought plain, unfertilized soil because I didn't know what anything was haha. I used about 1.5 ft^3 of soil between all five pots.
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You may have to turn your head upside down to see this one, sorry guys :O
These are the lights I'm using, they seem to be okay. Very bright. I have them about 1.5-2ft above the plants. When the plants get bigger, I've been thinking about getting 1-2 more of these units and positioning them vertically so that the light will penetrate in from the sides instead of the canopy sucking up all the light.

Bright!
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This is where they live. There is currently no ventilation, but I'm going to put a small fan inside the foil enclosure blowing along the edge so that it's not blowing directly onto the plants, but still circulating air.
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@Snow Crash & Snafu1236: From the sounds of it, the first place I'm going to start is by testing the pH of the soil, and the pH of the water I'm using, and correct levels accordingly. I'm hoping to not have to get new soil and transplant them, but if it's absolutely necessary for these plants to grow I'll do it. As stated in the beginning of this post, I just want some clones. I will definitely get higher quality soil (and maybe bigger buckets?) for those guys. Hell, I may even learn how to make a hydroponic system since apparently soil isn't the way to go from what I'm hearing

You want air blowing on the plants. Enough airflow to cause the plants to vibrate somewhat will encourage thicker stems and help keep heat down. Be sure that airflow moves in and out of the grow area, rather than only recirculating the air inside.

Those T5's can only support healthy plant growth about 7" or so (estimate) away from the bulbs. While fluorescents are known for their low heat, because they only illuminate a short distance away, a fan is often necessary to keep the plants close enough for strong growth.

To correct acidic soil, add garden lime (hydrated lime, dolomite lime, etc). It can be applied on the soil surface and allowed to adjust the pH of all liquids poured in. It can also be mixed with water and applied throughout all of the soil at once instead of just a top dressing. There are a number of fertilizers that are naturally very alkaline and they can be used instead of lime to raise soil pH.

To fix alkaline soil, you just water with an acidic solution adjusted with lemon juice &/or vinegar. Acidifying soil isn't usually as long-lasting a fix as neutralizing acid with lime. Lime stays in the soil awhile, continuing to adjust pH, while acids are usually more of a temporary fix.

I went to my shop today and got some supplies, including a pH test kit which included a bottle of ph-up solution and ph-down solution. I tested my tap water and the pH is almost 8. A few drops of ph-down and I'm at about 6 -6.5.
The guy at the shop said I should flush the plants with plain, pH neutral, water. (btw, the distilled water I got was pretty alkaline, I thought they were supposed to be neutral?) anyway I corrected all three gallons and I think my next step is to run that water through my soil, and then wait for it to dry, and then to continue feeding like normal, except now I'll be checking pH.

I also picked up some AzaMax Botanical Insecticide, Miticide, and Nematicide since I have a small fungus knat issue. Occasionally I'll see 1-3 flying around, so I think I'll use that stuff 1/2 strength.

edit: I also wanted to add that I will be checking the drainage from the soil occansionally to check on it, and I'll use the advice for adjusting soil pH as well. Also, I lowered my lights. Thanks Mother's Finest.

[email protected] said:

I went to my shop today and got some supplies, including a pH test kit which included a bottle of ph-up solution and ph-down solution. I tested my tap water and the pH is almost 8. A few drops of ph-down and I'm at about 6 -6.5.
The guy at the shop said I should flush the plants with plain, pH neutral, water. (btw, the distilled water I got was pretty alkaline, I thought they were supposed to be neutral?) anyway I corrected all three gallons and I think my next step is to run that water through my soil, and then wait for it to dry, and then to continue feeding like normal, except now I'll be checking pH.

I also picked up some AzaMax Botanical Insecticide, Miticide, and Nematicide since I have a small fungus knat issue. Occasionally I'll see 1-3 flying around, so I think I'll use that stuff 1/2 strength.

edit: I also wanted to add that I will be checking the drainage from the soil occansionally to check on it, and I'll use the advice for adjusting soil pH as well. Also, I lowered my lights. Thanks Mother's Finest.

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Distilled water won't have enough dissolved solids to register an accurate pH. The term, pH represents the number of H+ and OH- contained in the water. More OH- than H+ and you get either more acidic or more basic (I'm not sure atm). With distilled water, just a slight deviance of H+ to OH- will make a huge difference in the testing of the pH. For the sake of discussion distilled and deionized water will always have a neutral pH because in essence it has NO pH at all. No ... Power of Hydrogen.

For this reason, and others, Reverse Osmosis filtered water is far more suitable for growing plants with than Distilled. I always find it odd that people opt for distilled water when they can have RO filtered for exactly the same price.

Fungus gnats can be quickly eradicated with a Hot Shot No Pest Strip. They are sold in most places and need to be in a well ventilated area. Fortunately, grow rooms are the best ventilated area around. I've wiped out a plague of fungus gnats in a week with the thing. Don't ever see one now.

hope ya didnt buy all them diff ph testers. a half asses reg tester is all you need, they can all read the same thing. ph is ph. no need for 1 for food and 1 for soil. and shouldnt need any other lime other than what it already comes with or your going to have to much. the lime that is in it new and the rigtht ph water will adjust the ph all you need. unless the soil is old and abused the lime lasts a long time.
you little spots look like slight rust disease from the plants ph being off and was slightly deff