I have a couple questions. What would be a reasonable ppm for 4-5" tomato seedlings? The seedlings have just been transplanted from six cell nursery packs to 16 oz plastic cups. I water until 10-20% runoff each time. I Ph my solution to 5.7-5.8 and runoff comes out at 6.2-6.3. I started my tomatoes at 300-400 ppm with General Hydroponics 3 part. They were doing great for the past week or so. However, some of the cotyledon leaves have gotten just a tinge of purple on them, and some of the top leaves have turned a bit yellow-green instead of deep green. I bumped the solution up to 600 today. Is that strong enough? I saw an online feed chart which stated tomatoes should have a ppm range from 1400-3500. That seems strong, should I really approach such high ppm numbers so quickly?

So far my peppers are loving life. They are still in the six cell nursery packs. They are receiving 320-360 ppm solution at Ph 5.7-5.8. So far so good with my peppers.

Any advice is welcomed. If there is interest from folks considering using coco I would be happy to document my progress with some weekly photos.

Looks like your Atami B'Cuzz brand is fine. I'm pointing this out, just because there is a difference between coir and fiber. The whole coir has organic particles who decompose over time and will screw-up the PH over time, same as Peat Moss. While processed FIBER only (as Atami's seems to be) has no such components and hence is a way better.

As for tomato nutrients, there may be some issues that people who use commercial products (without understanding formulas and actual compositions) may run in trouble. Actually, it will happen when using half of the concentration or go higher with a specific mix or product.

Let me try to keep it simple and not go into technical details:

So let's have a look at a rather classical (but simplified) tomato formula in actual PPM content. This is needed to understand the maths behind the scene.

N=150
P=50
K=200
Ca=160
Mg=50
S=68

Nothing fancy about that and it totals around 650 PPM which is rather low compared what some other sources may tell, - but actually a proven and scientifically tested formula so far. As well in composition, as in concentration.

Trouble may come if you cut it down by 50%, or in other words, if you use this composition at half strength (some 325 PPM) FOR TOO LONG.

Because you'll then have most exactly:
N=75
P=25
K=100
Ca=80
Mg=25
S=34

Even if this may still look Ok to someone who doesn't understand formulas, it's not what actually reflects the needs of small tomato plants. A perfectly balanced and appropriate formula for younger plants would rather look like this:

N=70
P=50
K=120
Ca=150
Mg=40
S=56

As long as your plants are rather small seedlings, your original product or mix used in half strength, might just do the deal for a while, but it will not be appropriate for long. If you leave your plants for too long with this diet, you'll have deficiency problems from the start!

Now the reverse case: let's imagine you would like to go as high as 1200+ PPM, you would end-up with 300 PPM of Nitrogen, which is WAY to high. Considering that 150 PPM of Nitrogen is rather conservative, there might be formulas that have 170-200 Nitrogen content. Go as high as 3500 PPM and end up with 600+ PPM of Nitrogen! That is not what you want, do you? Anyway, I don't know who came up with those 3000+ first, but in my understanding it's just nuts or a typing error!

Again in brief and back to the basics: a nutrient formula is always calculated for a specific concentration. That is why people who literally respect manufacturers instruction do generally fine. If you change those by much as in 50% or 200%, and don't actually know the composition or PPM content of each element, - you are just screwing it all up and run into trouble for sure.

Furthermore, as you can see - total concentration (as 600 PPM you mentioned) doesn't say much about actual PPM-content of each element or a good balance. I anyway suggest to get as soon as possible to the actual suggested manufacturers concentration. Not rushing it, but do not wait signs of deficiency either, to finally get to it and (almost) keep it.

PS: I know, this might be a bit too specialized for some folks, and it's obvious that one has not much choice when using a single product (and need to compromise) for starting seedlings. Though I hope expressing it in real figures will help understanding how to compromise and better keep a formula in the limits of it's original balance and composition.

It looks like when I use 6 ml/gal floramicro and 10 ml/gal florabloom my nutrient composition would be

N= 78
P= 62
K= 103
Ca= 80
Mg= 39
S= 52

So I am looking considerably short on Ca and a bit short on K. I have Cal Mag Plus from Botanicare (N=2%, Ca=3%, Mg=1.2%, Iron= 0.1%). Is it necessary to try to remedy the shortage? Am I close enough? Could you venture a guess as to an application rate of Cal Mag to remedy the shortage in the Floraseries. I also have Liquid Karma from Botanicare which could help remedy the K shortage ( N=0.1 %, P=0.1%, and K=0.5%)

Do you happen to have a ppm breakdown for peppers as well (california wonder peppers is the variety)? Or is there a website I could consult to find such information for various crops?

Thank you so much for your help Jean-luc. I would love to surprise my mother with some fresh tomatoes and peppers come winter time. Not to mention the sense of accomplishment from completing a project successfully.

I've been using 16ml grow, 6ml bloom, 5ml micro, and 5ml cal-mag all summer long with fantastic results on my cukes, peppers, and maters. the tomatoes are on rockwool slabs, and the cukes and peppers are in waterfarms.

coco is quite sensitive to pH so make sure you let your nutrient mix settle for a little while so you can get an accurate pH reading.

coco tends to bind up magnesium or calcium and give back potassium so be on the lookout for ca/mg issues. adding more won't help if its locked out.

N= 78
P= 62
K= 103
Ca= 80
Mg= 39
S= 52

I notice you didn't use any floragrow in your mix. why not try a 2:2:1 ratio of grow:micro:bloom and adjust the quantity to 650 ppm. I think that'll fairly balance your nutrient. a little light on calcium won't hurt too much in vegative growth. the purple leaves you mentioned sounds like potassium deficiency (K).
I've used GH flora series to grow toms before and had good results without using any additional supplements. Of course, I wasn't using coir medium so YMMV.
And please, do post pics so we can see how things progress.

I am glad I could help so far and that you instantly understood what it was about. Unfortunately I can't be of any help when it comes to commercial products and mixing them, as I do not use any of them due to the fact that they are not available here. I only use self-made nutrients.

Still. some more rather important details and hints to avoid nutrient related issues now and in the future - when mixing and calculating nutrients or different products:

1. Make sure that you do not confuse P2O5 and actual P-content as well as K2O with actual K-content or even MgO versus Mg-content in PPM!

2. I'd take care to have sufficient Ca and Mg (+S) all along the way. Most importantly Ca, as it is one of the most immobile elements. If you know how to mix different nutrients and measure the exact quantity, you are only one step away from adding Calcium nitrate and/or Magnesium sulfate, to assure Ca, Mg and S content! When using Calcium Nitrate, be sue to use it as a supplementary (separate) component!

3. Peppers and Tomatoes may be grown together in the same setup, but from my experience only with a conservative and rather low concentrate "hoagland-like" mix. The main and most important difference is the lower Nitrogen needs of tomatoes. At PH 6.0 both should do fine. At http://www.howardresh.com/ you will find detailed specs (formula PH etc) about pepper tomato and cucumber growing in hydro. Don't l be fooled by the commercial outfit of the page (there is valuable info) and pleease consider that Dr. Resh is pushing a bit with his formulas, especially with K-content, well just saying ;-)

I've heard about Ca and Mg binding and P "output" of coco firstly in the context that it was only assumed according to the composition of special coco-nutrients. I am not sure if it is true for pure fibre anyway. I also guess that if it happens, its importance will greatly depend on the volume of your media. If you use only a little media (processed and inert coco fiber) I wonder what could possibly be held- or given back with that, honestly. Also, as I said earlier: processed and real fiber shouldn't have much impact on PH. But you'll find out by yourself anyway.

Concerning P2O5 and actual P-content: a while ago I was confused with NPK-data and actual PPM myself and posted a problem here, which I actually solved by myself at the end. You may read the topic here (scroll down a bit) http://forums.gardenweb.com/forums/load/hydro/msg0603442432330.html?7

Here is a very useful chart for tomato growing which was issued originally by the University of Florida. I have been successfully growing my tomatoes with the aid of this chart, by using but simplifying the data a bit
. Supplementary explanation: 1st colums = seedling to first cluster, followed by 2nd, 3rd cluster, etc.

Personal @ ballplayer: Unfortunately I have decided that this will be my last post here, as I have been running consecutively in some allelopathic trouble here LOL. Just in case, you'd like to keep in touch, leave me some info here, where to pic you up elsewhere (forum or whatever).

Otherwise, take care and be good!
Jean-Luc