Coco grow. Leaves canoeing and tips turning light yellow. *PICS*

So this is about my 3rd grow. I have 9 seedlings going in coco. Three just shot up and are growing really fast, but now those three are having canoeing of the leaves and there is a hint of the tips turning light yellow and the leaves are not real dark, maybe a bit too light green, but don't look REAL bad to me. On the other hand my other little seedlings I have are growing a good bit slower and are having bad problems with the light green leaves and the tips turning a real light yellow. I'm using botanicare pro grow (the recommended dose for the appropriate week) and cal-mag (1 tsp./gallon), as well as the liquid karma. I'm using R/O water ph'd to between 5.8-6.2. This is my first time growing in coco, but from what I'm heard it is simple. I have checked the PH of the runoff and it is also 5.8-6.2. I also have 3 other plants that are flowering right now that I transplanted from soil to coco and they are doing amazing, feeding them the botanicare pro bloom, cannaboost, and cal-mag. Common sense would tell me the plant should be able to uptake the nutes no prob in this ph range. And with R/O water I figure it should be pretty pure so not too much extra nutes in it (I.E. over abundance). I looked at the plant problem page and it really does almost look like nitrogen def. but I thought I was giving them plenty (especially the little seedlings with only 1 node). Sorry if some of the pics are blurry, it's an old camera. I'm stumped and missing something. If anyone can help it'd be much appreciated. Thanks!

And also I will add, right now the plants are just in some small little pots i got from the dollar store. Maybe a quart and a half? And I only water when they are real dry, every 2 days, and feed every watering.

Im going to move to dtw section you might get more help there

Canoeing can be the result of high heat or too close to lamps. The plant is trying to dissipate moisture to cool off resulting in the leaves turning up. As for the yellowing it could be lots of things, potential over fertalizing. My plants from seed often get that yellowing thing going on when they're young, the usually grow out of it. I say make sure your heat is right and the plants aren't too close to the light and make sure your not over fertalizing and they should do fine.

They look pretty healthy for the most part, I wouldn't worry too much

Alright hellraizer, wasn't sure about subcategories. Yeh sheik I did think about that. I have been putting them under my 400w hps for 12 hours a day because they grow super fast and they are at least 2 feet away and off to the side, not directly under it. Also I have a fan blowing directly on the bulb in hopes it would displace the heat. My 3 flowering plants are fine, no canoeing and they are alot closer. And then i put them under cfls at 10 pm until 4 am. Just was trying to catch the problem before it escalated. I don't like posting over every little problem, but being that it's my first coco grow wanted to check and make sure I wasn't missing something. Thanks.

They're burning.

Unlike soil, you do not have to dry out coco in-between watering (read below). You also don't need to feed them nutrient with every watering unless you are running drain-to-waste with a bit of runoff at each regular watering.

Overfertilisation can look like a nutrient deficiency because it actually causes the deficiency by locking out certain nutrients through the over-use of other nutrients. However, it is nearly always accompanied by Nitrogen tip and leaf burn - like in your photos.

So let me guess . . . the smaller plants are doing worse than the bigger plants, right? That's an easy way to tell nutrient burn versus deficiency. As a general rule, if the bigger plants are yellowing and the smaller plants are doing alright, you need to feed them more. If the smaller plants are yellow and the bigger plants are doing alright, you are feeding them too much.

In fact, seedlings don't need much food at all - they have all they need in their cotyledons (small round leaves) to get them through the first 1-2 weeks of their lives. When raising seedlings in coco, all you really need to do is pre-buffer and pre-ignite the coco with a very weak (1/4 strength) nutrient solution and then use plain water until they are almost two weeks old. Then you can start to feed them properly.

I'm also going to have another guess that the formula you are using is for RO water, right? Therefore the instructions likely call for a higher ratio (concentration) of nutrient than using tap water. Plus you're using cal-mag - which is high in nitrogen - and Liquid Karma - which also contains NPK (much too high K for seedlings, IMO). Altogether, you probably have no idea exactly how much of each nutrient is in your coco.

That Botanicare Pro Grow also looks like it has enough calcium and magnesium in it already, so I'm not sure why you're adding cal-mag at this stage - you should only really be using it to pre-ignite your coco and/or if you see signs of a deficiency.

Also, what sort of coco are you using? Has it been flushed and/or treated/pre-buffered? If it hasn't been flushed, it likely contains sea salt (coconut coir grows and is generally processed in coastal areas). If it's already been pre-buffered and treated, it likely already has nutrient in it. Either one can burn seedlings if you continue to feed them without flushing.

The real problem, though, is that you are adding nutrients and then drying out your pots, which increases the concentration of nutrients as the water evaporates - until all you're left with is a near-dry pot of coco full of dry salts. Add a bit of heat from your lighting to the equation - which causes your leaves to perspire and your pots to dry out even faster - and you quickly burn your little seedlings from the roots up (that's why they don't grow - burnt leaves are the least of your worries, as burned roots can't be seen and will stunt growth).

The solution is to flush all your plants with plain water and go easy on the nutrient. After thoroughly flushing, water them with a very week nutrient solution (1/4 strength; just the nutrient - no Liquid Karma, Cal-Mag or other stuff) and leave them to recover. Raise your lights a little bit to reduce heat stress, and they should start to grow out of it over the next few days to a week.

The #1 mistake all noobs make is overfertilising - I'd say it accounts for most of the plant problems I see on these boards.

Just to quantify, I had a look at the Botanicare recommended dosage for coco coir and it does say to use extra Cal-Mag initially if you are using RO water. This is to pre-ignite the coco with calcium and magnesium, as coco will lock up more of each than other mediums. (That's what I meant by "pre-ignite" in my post above.)

Most tap water, on the other hand, has calcium already in it - more calcium if it is from a limestone groundwater source. That's why you need to add extra, initially, when using RO water. However, once you have pre-ignited the coco, there is less need for Cal-Mag, which should only be used sparingly if there is a known risk of deficiency.

One way to solve all these issues it to simply use a dedicated coco nutrient, as most coco nutes have extra Cal-Mag for the above reasons. They also contain slightly less potasium, as K is released by coco as it breaks down.

Thanks alot Prawn, for taking the time to help me out. I had been using fox farms soil and my last grow had a real bad case of over-fertilizing and I never gave them nutes, just what was in the soil. So I know what u mean about the number one noob mistake. I have just been reading up alot of the forum about coco and alot of people are talking about how you HAVE to add cal-mag as the coco doesn't have anything in it and many people are talking about how cal-mag def. is common in coco, so I guess I was just trying to beat it to the punch. Also I am using the hydrofarm cocotek coir, and from what I have read also, the coir these days generally comes prerinsed, or pure. I wasn't aware about the pre-ignition deal with the cal-mag. The back of the bottle on the botanicare really doesn't give a whole lot of specific info for coir, just the general doses. And as a matter of fact I flushed the three biggest seedlings in veg last night and i actually do believe that they already look a bit better, so it gave me some hope. Now I guess I'll do that for the rest. Thanks alot Prawn for all the info, sometimes it's hard to find info that applies to my specific situation. I'll definitely take your advice and sent some +rep ur way buddy!

And about the drying out before watering, I had seen some people say it's best to let it get bone dry and some people say you can't over water, so I had just been treating it like soil to be on the safe side.

The key to coco is to keep it right between dry and wet! Once you learn that and apply it to multible feeding
you will kill it hands down and you will find they wont burn as easy!

I don't use cal-mag and never have. I use a dedicated coco nutrient with a good ratio of calcium and magnesium, and my tap water also contains calcium and traces of magnesium - as does most tap water that comes from ground (especially limestone) sources.

Most name brand cocos come pre-flushed - so you generally don't have to worry about sea salt (coconuts grow by the sea and the husks are processed along the coast - unflushed coco coir contains a lot of salt), while many are pre-buffered to stabilise pH and come pre-infused with small amounts of nutrient - mainly calcium - so that you can start growing straight away. Canna is one such coir and is probably the yardstick to measure other cocos by, but there are some other good ones out there I've tried.

So really, you only need Cal-Mag if you have a known shortage of it in your nutrient, water or have a particular strain that is a bit of a magnesium hog (some indicas). If your nutrient is not coco-specific and is lacking in cal-mag, and/or you're using RO water that doesn't contain natural amounts of calcium (like you are), then you may need it. But typically, once you have pre-ignited/pre-infused/pre-charged (whatever you want to call it!) your coco with enough cal-mag that it no longer locks up these two nutrients, you shouldn't need to use much more.

One thing I did notice is you've mixed perlite in with your coco. I'm not sure what brand coco you're using, but if it's a no-name brand or you suspect it may not be good quality, that could be part of your problem: the salt needs to be flushed from it first (try using warm water if that's the case, it dissolves salt and flushes better than cold water). Once you've flushed with plain water, you can add a very weak (1/4 strength) nutrient solution.

As for the perlite, you don't need it in coco - it is already porous enough (assuming you are using a decent coco coir to begin with). As long asyou have good drainage, you cannot overwater coco and in fact the more you water it, the better your results. I water my pots four times a day (using a timer) and sometimes six times a day during summer. Short bursts of fresh nutrient solution with a tiny bit of runoff are what work best with coco. Watering actually introduces more oxygen to the root zone as it pulls air down with it, while the coco itself acts like a sponge: the physical act of expanding and contracting as the coco is watered and dried acts to pull air into the root zone.

And that's the reason why the more you water, the faster your plants grow. Letting your pots dry out is only going to increase your chances of burning your plants - especially seedlings - but don't panic if they do dry out a bit; just give them some water and they'll be right as rain.

Cool, yeh I'm using Hydrofarm cocotek, which i felt should be a fairly high grade coco. I will definitely look into some coco specific nutes in the near future. I am glad you told me about the watering. I have noticed that no matter how much water i flush, the plants don't even flinch, which is awesome. I really don't know why everyone hasn't switched to coco! I mainly put the perlite in there, because my major problem with my ffof grows was it was retaining so much water and burning the hell out of my plants. So just to play it safe with my inexperience with coco, i added the perlite. They are growing amazing though. Only about 2 1/2 weeks old and about 6 nodes and the biggest plant is only about 7" tall. Makes me feel good after failing at hydro. Best thing I ever found. Thanks for all the input!

Coco IS hydro. That's what a lot of people don't realise. It's simply another hydroponic medium that happens to have some similar properties to soil. Just like in hydro, as long as you have good drainage, the more you water the better the results.

But the best thing I love about coco is it's insurance: if a pump or timer brakes and you don't water it for 2-3 days you don't lose your entire crop - as you would with most other hydro systems.