Yellowing Leaves

alright, i have four young seedlings. three of them are a little over three weeks old, and the other is a little over two weeks old. just yesterday i noticed a slight discoloration of the leaf tip of Plant B (three weeks old). At the end of the day, i checked on my plants, and the tip of its leaf had turned a pale yellow color, and was dried and had cracked.

then this morning i looked at my plants before work, and Plant A (two weeks old) was beginning to show the same discoloration of the very tips of the leaves that Plant B had showed in the beginning.

Plant A (two weeks old) and Plant B (three weeks old) are my smallest plants. Plant C and Plant D are much bigger than them, and i'm thinking that something is up that is causing a stunted/slower growth in A and B.

My Specs:
-Each plant is in its own 8" pot in Miracle Gro Potting Mix
-My lamp has two 40 watt full spectrum verilux bulbs - 2100 lumens each
-My lighting cycle is 17/7, and a fan blows on low setting in the general direction of the plants to keep the air moving during the 17 lighting hours.
-I water each plant with about 5 ounces of distilled water every three days, and i do not mist them
-I don't know the ph of my soil or anything, i haven't bought a ph meter yet... but i plan to at the end of this week.
-I don't use any nutes as of now.
-The temperature is always between 63-70 degrees fahrenheit
-The humidity is controlled by the thermostat, and is around 35%

FYI: All four of my plants used to be about 6-7 inches tall and very leggy, but i repotted and buried them down to about 1" from the first set of true leaves, and that's also when i bought the new lamp and moved it to about 1" away from their leaves. Since then, they have grown a lot.

So my question is this: What can i do about this strange yellowing of the leaves? Is it a lack of nitrogen? Light-burn? Poor drainage? Should i mist my plants? I hate to see my poor little plants suffer.

Thanks in advance everyone




P.S. i know what you're gonna say - i should have searched the forums before posting such a popular question. but i looked for like 20 minutes and i didn't find anything that really answered my question.

also, i forgot - i really would like to start using nutes. is it still too early for this? and if so, then when is the right time to start? if not, what n-p-k ratio should i think about using for some awesome vegetative growth?

Miracle grow not the best but will do
Lighting should be 18/6
Must ph all liquids before adding to plants!
Daytime temp should be higher around 80
Humidty should be at least 50

Part 1 Contributed by: Bongaloid
Part 2 : Bush_Grower

First time growers frequently:
Overwater their medium based plants. When you pot your plant, judge its weight dry by hefting. Then, water the plant thoroughly, until water runs through the drain holes. Heft it again. When your pot feels as nearly as light as it did dry, its time to water again. Overfeed their plants. As MrSoul says, beginners rarely under do anything. When all else fails, follow the directions on the fertilizer bottle. [Editor's note: dont follow GH's instructions! Use @ 1/4 their recommended strength, or follow recipes in the FAQ]
Overanalyze their grow. A first grow is like a first born child: you pay attention to every little thing that happens. Further, you worry at the first sign something may be wrong. Pay attention to what happens in your grow, but do not try and find a remedy for every yellow leaf. Frequently, the remedy of flushing your medium causes more problems than it solves. Be responsive when things go wrong, but be conservative in your remedies.
Overspend on grow supplies. New growers frequently commit themselves to unrealistic and expensive first grows. It is much more efficient to learn to grow and then invest in high end equipment rather than the other way around. Most experienced growers don't have room for all of the grow paraphernalia they aren't using. As you will see throughout this FAQ: K-I-S-S.
Overpost. Try the search engine first. Chances are good that any question you can think of has been asked and answered before.
Talk about their grow. Don't tell anybody that does not have to know. How can you expect anybody else to keep a secret that you cannot.
Part 2:
Contributed by: Bush_Grower
1. Don't Overwater
Overwatering kills marijuana plants. Water once the top few inches of the soil dries out.
Hydroponics is harder to over-water than soil, due to the abundance of water roots.
2. Don't Tell People
Why? They will only be jealous. People love to feel important and that is why they will tell other people; because others will listen to them.
Keep it to yourself.
3. Touch/kill Germinating Seeds
It can take up to 10 days for a seed to sprout. The paper towel method is not recommended because you must handle the seeds when transferring them from the paper towel to your growing medium.
4. Grow seeds from seeded marijuana (hermaphrodite seeds)
Unless you are prepared for possible disappointments don’t use "unknown" seeds. This is why people buy seeds from seedbanks.
Self-seeding MJ is produced from hermaphrodite plants or a very stunted and late flowering male the grower did not notice. Flowered hermi seeds will produce tall late flowering females coupled with early flowering males.
5. Don't Over-fertilize
Fertilize after first 2 spiked leaves appear.
Start with 25% of recommended label strengths and work your way up. If the leaves suddenly twist or fold under, Leach and Spray with pure water for several days!
Don’t fertilize your plants every time you water! (Soil)
A common watering schedule is to fertilize at full strength, then water at half or quarter strength. This prevents excess salt buildup, leaf and root burn. In addition, don’t water at full strength if the medium is too dry – root burn can occur.
As a precaution, leach the plants with lots of pure water every 2-4 weeks.
6. Don't Under-fertilize
Under-fertilizing is less common. If you prefer to give the plant ‘just enough nutrients’, use a organic soil mixture with blood meal and bone meal or some slow release fertilizer with micro nutrients.
7. Don't Start with Clones
Start with seeds. Bugs are a pain, as are plant diseases. Many growers are able to grow indoors without pest problems for years. Another grower’s cuttings are almost guaranteed to have diseases &/or pests.
8. Don't Provide A Bad Environment
Always provide air circulation and fresh air even during the night cycle. All the air indoors should be replaced every 5-10 minutes.
Humidity between 30-70% temp aim for around 75-85' Even seedlings need a gentle fan to strengthen the stems.
9. Don't Harvest Too Early
25% of the weight will form in the last 2 weeks. Begin flushing with 100% pH’d water when the pistil are 25% brown. Harvest when the plants have totally stopped growing and the white pistils are at least 50-75% brown.
*NOTE: Outdoors if security is a factor make your own call on when to sacrifice the fields. Also take buds continuously in case of thieves.

Common questions:
Q. Can marijuana grow in a northern climate?
Marijuana plants can grow anywhere corn can grow. All it needs is three growing months - seed to harvest. 2 if started indoors!

Q. Why do I have to buy seeds? Why can't I use my own that I picked from my own stash?
Most people desire, and want to be guaranteed, certain characteristics in their mature female plants. The seeds from any weed will all grow into something different. This is unprofitable and inefficient. As opposed to knowing the single set of requirements for your entire crop, you must provide a different set of requirements for each of your plants.

Q. What is better for a new grower - hydroponics or soil?
I believe the all around "better", more convenient setup is soil. Hydro makes plants grow faster, but won't make your buds more potent than soil. Hydro should be attempted after you have a few successful soil crops under your belt.
If you are starting from seed and growing for personal, soil is the practical growing medium. If the crop is started with clones and is commercial, a hydroponics setup is more practical.

Q. Why are my seedlings stretching?
Low light conditions. They also need a gentle wind. Plants will also stretch when subjected to conditions of high humidity.

Q. What kind of lights should I use?
Cheap 4 ft. cool white fluorescent tubes : for germination/seedlings
400 watt Metal halide/HPS : for personal home growers
1000 watt Metal halide/HPS : for some personal growers and commercial growers.
*Use at least 40 watts per sq. foot of grow space.

Q. How far should the lights be from the plants?
Fluorescent: tips of leaves almost touching bulbs
400 watt halide : two feet away from seedlings and one foot away from grown plants
1000 watt halide: four feet away from seedlings and two feet away from grown plants

heh, ok, thanks mogie. i don't overwater my plants or overspend, but i might overanalyze the grow lol

thanks for the info though, i didn't know that a gentle wind increases stem strength! i'm glad that i have that fan going.

Crayola said:

heh, ok, thanks mogie. i don't overwater my plants or overspend, but i might overanalyze the grow lol

thanks for the info though, i didn't know that a gentle wind increases stem strength! i'm glad that i have that fan going.

Click to expand...

I'm not sure of the ph of distilled water, look into that, and MG Soil usually has nutrients in it, It's way to early for that, could be causing the leaf problem you discribe,
. Nutrients don't really need to be introduced till a month later.

u need a better light they bad for their size to much nuits not enoughf heat plus u got 2v much perilite their babbys m8 re pot them flush them with pure water mist them then cut down on nuits for now they will live iv got 4 crops at the moment remember 75 _8o degrees heat fan on then and trust me cut down on the nuits GOOD LUCK?

Thank you for so much information. I am currently seeing first-hand how growing from seeds picked from a plant can be totally different from the "mother". I got a about 30 seeds off my L.A.Con. plant a couple months ago, planted 7, and am watching 2 different types (and 1 Totally unique) grow. 3 are uniform yellowish-green, have been since sprouts, and appear healthy, happy, and growing at a good rate..... It just blows my mind that they're yellow. 3 are uniform green, and one is green with red in the new-growth, and has a very different shape to its leaves. All are in soil, fed the same, watered the same (with 6.2-6.5ph), and getting really good sun. My hubby bought his seeds though, and his obviously have great genetics, cuz his are growing exactly symetrical (when you look down on them, every leaf lines up perfectly across from/above each other) and each seedling looks exactly like the others of the same stain. Guess I'll cross my fingers, and give them lots of love, and hope some turn out as good as the mother was!!