EC inquiry for lettuce and leafy vegetables!

lucas_formulasMarch 5, 2010

I would like to start a little inquiry about how various nutrient concentrations used by individuals could possibly be.

Let's start with lettuce and leafy vegetables in general. Please be brief and just give the mS/cm value (for some this means EC). In case you're going by ppm, PLEASE convert from conversion rate used by your instrument (500/700) to mS/cm (EC) and post this data ONLY.

Please specify as follows if possible:

A. Very first concentration you use plus day nutrients are added to plain water (after germination, 1, 2, 3 days after germination etc).

B. seedlings with 4-6 leafs until transplant to NFT or else

C. main concentration from transplant to maturity

D. only IF using various concentrations from transplant to maturity.

Roles: Only PERSONAL EXPERIENCE and strategies, or direct knowledge about 3rd parties please. No google results, commonly spread data, or graphs or tables PLEASE! No vague data, as in 0.9-1.7 and If only possible, do NOT care what others may post here or use.

I guess the outcome (average or variety) may be very interesting for each- and everyone ;-)

Thanks for participating!

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I have found that some plants can be grouped and fed the same way while others require special attention.

Lettuce is one of the special ones. By this I mean it will practically grow in plain tap water. Another special plant are the hot peppers, which are my favorites besides Herbs to grow.

Before I get to any level of detail, I would like to point out that my experience is in using either Deep Water Culture, or a Wick method. I have not done much Ebb and Flow or NFT hydroponics.

That said, I found it extremely difficult to find ANY accurate information on the proper solution strength levels on the internet. Maybe its because I was growing mostly tomatoes, herbs, and hot peppers? What I found in those charts were exteme highs in the PPM or EC levels. When I first tried those levels, I found my plants mutating, leaves curling, dimples on the leaves, spots on the leaves, and all sorts of issues.

So all my current EC PPM levels are in my head, as I have found my plants grow faster, picture perfect, and have tons more fruit if I use much, much less that what is recommended.

Next I would say that most seedlings require a most mild solution. In this regard, I would recommend that you shake or mix your nutrients well befor adding them to your system as at first you will be using much smaller doses.

For lettuce I start these plants out in my Aerogarden because Lettuce requires little light, and I can take the plant and its medium, and just move it into my hdyroponic system. For starters, I only use plain old tap water. My water is extremely clean where I live. The EC is .05 from the tap. It does contain some Chlorine and Floride, but that is it.

Once those seedlings get their first set of true leaves, for Lettuce I set the EC at .15, Peppers about .20. For Lettuce I use the One Part Grow, and for Peppers I start them out and grow them their entire life in One Part Bloom. Tomatoe plants I start out at .50 and do the same, checking the EC daily to see how they are doing. For a maximum on Tomato plants, I typically end up with a heavy bearing plant at 10 feet tall with its daily solution set to 2.5 EC, of which it takes two days for that one plant to use all the nutrients although it uses about 10 gallons of water in that 48 hour period.

In Deep Water Culture, the container size seems to make a difference on the strength of the solution. For example trying to set the EC to 2.5 in a two gallon bucket does not work as the plant cannot drink enough water, because as it does, the solution becomes to strong.

Therefore, depending on the size and type of plant, the container does tend to control how much nutients you can safely add. I have never tried a container larger than 5 gallons for one plant.

As the plants grow, I check the solution, and depending on how fast they use it up, I increase the strength. For example, if the Lettuce is initially set to .20 and at the end of the week the solution is only .15, then next week I leave the solution the same strength. If the plant uses all but maybe .05 of the solution, next week I will bump it up to .25.

I only increase the EC until what I know is the maximum EC for each plant. For Peppers its .75 EC. What I mean is that some of my larger Pepper Plants have used up 95% of the solution in a 24 hour period of time, but I do not bump up the EC because when I do, bad things happen to my plant.

I can tell you that I have passed on this knowledge to many other hydroponic growers and they have all verified that my recommendations work very well, much better than what they were previously doing.

My friend works at a hdro shop, and I find myself talking to many people especailly on the weekends. I have a small following of growers who constantly ask for me, or come in only when they know I am there.

My next soul searching experiment is to create a Deep Water Culture System that allows me to fill the container the plant grows into with solution, which the plant can consume until the water is used up or very low. This means an even lower EC solution. As my idea would be to create a large container that would feed all the plants for a week. So the one container would contain a set solution. This would then be pumped to each plant container, then at the end of a 24 hour cycle, drained, flushed with clean water, then filled back up with the same solution.

    Bookmark   March 7, 2010 at 1:24PM
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Good for you indeed mrpepper!
But look, the objective of this thread was (at least in the first place) to draw down some usable data as in what I suggested in A, B, C or D. Would you be so kind and at least fill in one or more of those? Thanks!

I agree with you though that it is all in our heads ;-)
Well it's always good to be convincing, make people confident and put them at your side if you do sales and business. But unfortunately that is not what I was actually looking for or wanting to have confirmed ;-)

Let's keep it with lettuce first: in soil (and in hydro it shouldn't be much different) lettuce is not taking up much nitrogen or other nutrients for an extended period of around 40 days - in fact the nitrogen uptake is VERY low in the beginning but nearly identical over an extended period. Later, growth becomes exponential and so is the nutrient uptake. Around day 45 (between 4-6 and 10 leafs) the curve starts to raise and just after folding (around day 70-80) it actually raises to the sky. This is leaned on a scientific study.

So any meticulous gradual feeding in very small steps as you propose (and practice as you say), doesn't actually make much sense (shouldn't be the way to go), neither in the first 30-40 days, nor from folding to maturity. Looks more to me that a more radical 2 or 3 step strategy would fit the curve best.

    Bookmark   March 7, 2010 at 10:12PM
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Ahh yes. Sorry about that. Did not realize you posted the thread. In that case, ignore any and all comments.

    Bookmark   March 8, 2010 at 1:13AM
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Nice to see you again too, "mrpepper" ;-)
But I actually thought that this kind of infos or input isn't about the thread starter or some personal stuff, - but about common sense and interest. That is what it was supposed to be anyway.

Or is this place already so full of envy, personal revenge, raining back on other's parades, pseudonyms and crap, that there is not much room left for anything purely informative or constructive?

    Bookmark   March 8, 2010 at 3:35AM
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I totally took notes, thank you mrpepper and lucas!

    Bookmark   March 8, 2010 at 10:03AM
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Peace not War . Thank for the info btw

    Bookmark   March 10, 2010 at 1:52AM
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There is nothing personal in my comments. Basically, if I do not see what I am doing as productive and conducive thing, I cease to do it.

In previous blog threads on this site, most of what I have stated, recommended or suggested was contradicted by Lucas Formulas.

I enjoy participating on this site not to show off my experience, but to share what I have done and been sucessful at, and to learn from others.

This does not mean because of differences between my suggestions and those of Lucas Formulas tuhat I will not participate on the forum.

However, this blog thread was posted by Lucas Formulas, and therefore I would not find it productive to post more suggestions about my experiences.

I am sure that Lucas Formulas is only expressing what they feel is the best information that they have. Perhaps its in the way that information is being posted, that could cause a lack of desire by others to post their information.

    Bookmark   March 13, 2010 at 11:33AM
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I can tell you that as a beginner I appreciate your info Mrpepper. I can see and understand how when someone contradicts you (in an attacking 'your so stupid' way) instead of offering their point of view as another alternative would be frustrating. I truly believe thats why this board isn't as active as it probably would be if people were a little less ...abrasive... in their responses.
Its obvious some people have way more experience and are confident in the way they do things, however I personally like to read about everyone's thoughts and advice in order to find the best way for ME. So I appreciate your info and I encourage you to keep offering more advice and info for us newbies!

    Bookmark   March 13, 2010 at 2:29PM
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>>There is nothing personal in my comments. Basically, if I do not see what I am doing as productive and conducive thing, I cease to do it.That's funny - because first you say that there is nothing personal in your comment, and after that you explain WHY it is personal.
I don't know about your understanding of "personal", but from my understanding, telling someone to ignore all comments, or ignoring the person (without even giving a reason in the first place) is the most direct and impolite way of expressing that it IS PERSONAL.

And please don't make it sound like I contradict "most" of what you have posted, because it was in fact the very same thing that you have posted twice but at different topics what I didn't agree with at all. Or was there something else?

How comes that you actually didn't realize who started this thread, and how is it that your comment didn't actually answer nor respect what was actually asked from my side to gather a set of options in the interest of all?

Why don't I agree at all with your recommendations and suggestions, or if you like with the description of how your strategy looks like? Well, because it truly confuses me as it rhymes with nothing I have ever experienced, seen or have heard of anywhere. If it had been just a bit closer to "the" or some model, I wouldn't even have comment it, but simply accept and adopt it as an example among others.

From my end, there is nothing wrong with having very special, distinct or even uncommon ways of doing and using hydroponics. But don't you wonder if you don't get agreement or produce consensus on every level with everyone on those... ;-)

    Bookmark   March 13, 2010 at 9:52PM
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I just started a modest NFT lettuce grow with three varieties (merlot, tango, and buttercrunch) x three plants each. (Just for the record, this is a mixed planting experiment with multiple varieties of basil and sage in the same tubes; hence, the plant count is small.) Anyway, after using 50/50 tapwater/distilled water for germination in rockwool, I have used EC around 1.0-1.35 (pH~6) for the first fifteen days thus far. Growth looking decent, and will likely bump up the EC as more leaves grow. However, my mini-NFT (I custom built for this experiment) is in a S-facing window where the light isn't as intense. Maybe I shouldn't bump the EC? Only time will tell. Will update later, and still waiting to see others' data.

    Bookmark   May 4, 2011 at 10:24AM
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