Hydro Basil or Broccoli requirements- Newbie, please advise!!

csung1(6)April 7, 2010

Hi all,

I'm still relatively new to hydroponics, and have a specific question about sweet basil and broccoli. I have DWC, 105W CFL, roughly 15/9 light (didnt get a timer yet, so i;m manually regulating light cycles). I start plants in one bucket, which has three net pot spots. Initially i had a broccoli, sweet basil, and pepper plant.. the pepper plant was started first, and really took off in the system; i've transferred it to its own 5gal DWC bucket now and its doing great. the broccoli and sweet basil however, are still pretty small, and are still in the starter bucket. they might be nutrient locked.. (???)They are roughly on their third set of true leaves, but its been a month or so already.. i'm wondering if anyone has any insight regarding different requirements of these plants (i.e. why did the pepper do great, and the others not so great?). I keep pH roughly 6.0, i don't have a meter for nutrient concentration, i just roughly follow the directions on my nutes (1-2 tsp/gallon). Roots on both are not so spectacular.. don't have a picture, but could post if someone thinks that would help the diagnosis. Please help! Also, if someone has a good website reference specifically for SPECIFIC PH FOR SPECIFIC PLANT, or PPM FOR SPECIFIC PLANTS, that would a good start for me i think... thanks all very very much in advance,


oh yea also, i have one air pump per bucket. i don't know the EXACT output of these, but they shoudl be sufficient i imagine. airstone is one of the 4-5 inch long rectangular ones.. and the roots are not waterlogged, i have decent spacing between net pot and water level. thx!

also! i've read a lot about a general water flush for nutrient locked plants, but i don't exactly know what that means (yes i imagine, let it sit in just water for a while, but if someone suggests this, could you also outline the details for this flush? thx!)

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On the broccoli front: the only website I've come across that has grown broccoli in such detail is here (http://www.aerogardenmastery.com/drupal/content/aerogarden-modified-grow-broccoli).
Whilst he has done this in a very modified AeroGarden, the principle is the same - it's your very basic DWC unit. There are other non-AeroGarden grows he's completed which may be of interest also.
Compare the look of your broccoli for the same period with the one here, does it look the same size or much smaller?
From what you have said, your pH looks good and you are doing the DWC part fine - the only issue is what your EC is currently sat at, without a meter it's a bit of a guess, could you be underfeeding and stunting the growth? When you mix your nutes, do you know what the strength, as far as the instructions go, you are mixing too?

    Bookmark   April 8, 2010 at 4:56PM
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I'm starting broccoli this evening and did not know the recommended pH. One site recommended 7.0 (neutral). A couple said 6-7 and a couple others 6.5-7.0.


    Bookmark   April 8, 2010 at 7:51PM
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hey mikey, thanks for the reply. compared to that aerogarden site, the set up seems comparable at least, but my broccoli is much much smaller. i've grown broccoli in soil outdoors, and it looks like the pictures on that site, most noticeably the good thick main stem. my hydro broccoli is very thin, main stem is tiny, a few leaves only... i really don't know what the strength is, as far as the instructions go.. but what i've given is on the lower/middle end of the recommended mixture, so i'm hesitant to think that i'm severely underfeeding/stunting, or anything like that.. they just give the amount to mix, and thats it.. wordwiz, i've never heard of ph that high for any hydro plants (7.0), but if others know anything, please post. thanks again all,

    Bookmark   April 8, 2010 at 11:03PM
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hmm yea i'm seeing those 6.5-7.0 pH recommendations too now.. can anyone else with broccoli growing experience confirm this? would that be too high for the basil in the same bucket? thx

    Bookmark   April 9, 2010 at 9:42PM
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Well Im no expert but I did just harvest some Broccoli, I had my pH around 6.5 and ppm at around 1600 pretty much for the entire grow, I grow outside though, you sure you have enough light?

    Bookmark   April 10, 2010 at 4:33AM
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Growing Edge Magazine are going for a pH of 6.3, which is your recommended pH for brassicas of which broccoli is one.


With my basil, I set for 6.3 and kept it roughly along those lines, allowing it to rise a little before knocking it back. I've not really had any problems with basil, it's always been pretty hardy.

    Bookmark   April 10, 2010 at 4:40AM
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People following the threats about typical PH and nutrient concentrations should actually have understood and know the drill by now:

1. Charts and suggestions of Ideal PH of specific plants are derived from soil culture and do not apply with hydroponics in a direct way. Ideal PH for uptake of nutrients in hydroponics is known (between 5.8 and 6.2 as ideal and between 5.5 and 6.5 acceptable) and the same for most commonly cultivated plants, it may only vary slightly if some plants require more specific (uncommon) PH.

Recommendations for specific plants in ppm without giving the conversion rate is apparently still not understood as inaccurate and useless. Sorry, but there is no other way to tell this.

Either transfer to EC or give the conversion rate (500/700 or else) PLEASE!

My recommendation here:
Both may thrive better in a upper limit PH, inside the ideal scale: 6.2-6.5
As for the nutrient concentration, I'd recommend 1.6 - 1.8 mS/cm (EC) for maturing plants and "half nutrient strength" from the later for seedlings.
Nutrient concentrations may vary with climate: hot =somewhat lower, cool =somewhat higher
Here are chromatic analyses of broccoli and basil (italian), of elements (mg contained in 100g of raw, fresh matter).
Hint: this is not from dry matter, but from raw vegetables. Some of you may have good use for the data, connect the dots and even calculate their own formula, some may not even bother ;-)


Calcium, Ca=48
Iron, Fe=0,88
Magnesium, Mg=22
Phosphorus, P =66
Potassium, K=325
Sodium, Na=27
Zinc, Zn=0,4
Copper, Cu=0,045
Manganese, Mn=0.229


Calcium, Ca=177
Iron, Fe=3,17
Magnesium, Mg=64
Phosphorus, P=56
Potassium, K=295
Sodium, Na=4
Zinc, Zn=0,81
Copper, Cu=0,385
Manganese, Mn=1,148

    Bookmark   April 10, 2010 at 11:43PM
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Interesting plants these, nitrogen free ;-)

    Bookmark   April 11, 2010 at 12:59PM
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Don't you think so too ;-)
Unfortunately the Nitrogen content is not part of the USDA food analyses.
If you have got them, I'd love to get them from you of course...
Otherwise "connect the invisible dots" as suggested. :-)

    Bookmark   April 11, 2010 at 1:35PM
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Before this thread falls away, a quick question.

I've not grown broccoli in hydro. myself either, seeing the other website with his broccoli growing has got me wanting to try it myself.

So, should I stick to a 'vegetative' mix all the way through, or, at some point, switch to a 'blooom' type mixture part way through?

He has asked this and I'm unsure myself now, probably tempted to stick to the 'veg' nutes, any ideas anyone?


    Bookmark   April 17, 2010 at 5:32AM
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From the analyses of Broccoli it has quite an amount of potassium. Which is actually plausible because it has a "strong" stem structure and complex cellular mass that goes along with it. I'd not suggest a typical "vegetative formula" but a formula that has a ratio of N-K by at least 1-1.5 elementally speaking (as in N=160 - P=35/45 - K=220).

And I don't even know what a 'bloom' type mixture is, maybe someone can tell me for a change ;-)

    Bookmark   April 17, 2010 at 7:03AM
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Having a pH of 7 is still safe no matter what plants you're growing although 6.5 is ideal for most plants.

@lucas, a bloom mixture doesn't contain nitrogen, only phosphorus and potassium to help plants get through the blooming process...Some even say that it is best to get a bloom formula that has more potassium compared to phosphorus if you're using it in hydroponics because having more amount of phosphorus may only burn your plants.

    Bookmark   May 8, 2010 at 1:23AM
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Hi hydroponics_systems,
About ideal, acceptable and "still safe" pH there is some disagreement among "experts". Some push the safety level quite high, perhaps up to 7. Others do not agree and claim that the pH should even be hold under 6 by all means. In my humble opinion, 7 is NOT safe anymore with a number of species, while it might be the last borderline and in fact not lead to visible deficiencies with others. For instance, fast(er) growing species are much less susceptible to high pH as 7 than long term crops.

Also about a "bloom mixture" or a bloom formula, I do not agree that it doesn't contain any Nitrogen. This really depends on the definition of a "bloom mixture". There might be, actually there are some products or "mixtures" called "bloom" or containing bloom in the name, that have no Nitrogen, but that is not a general role.

Some may say that the Potassium content should be higher than the Phosphorus content... well I clearly say YES, of course it should. Any formula with scientific background ALWAYS has a much higher proportion of Potassium versus Phosphorus. Plants do not need any notable extra amounts of phosphorus for the blooming cycle. Most "non blooming" formulas contain already more phosphorus (as in 45-60 ppm) that plants would ever uptake or use for blooming. The still used (sometimes modified) Hoagland formulas mostly contain between 20-30 ppm of P only. Any amount that exceeds 50-60 ppm is a myth, a trend or some commercial indoctrination, perhaps has some M-J grower background. I challenge anybody reading this, giving me proof of any commonly plant grown hydroponically, that would ACTUALLY require more than 50-60 ppm of P at any growing stage (compared to 200-280 ppm of Potassium) to give a clear relation of let's say 1-3 minimum up to 1-5 versus P. I' am talking elemental PPM, not NPK conventional standard of course.

PS: In amounts used in most formulas, even if P is clearly overrated, it is not prone to be responsible for "burning" any plants. If used completely against any recommendations, it might though, - but that's not the point here. In case there is burn, it is not likely due to the (still) relatively low amount of Phosphorus itself but to the much higher amount of any other components or elements contained in any common formulas.

    Bookmark   May 8, 2010 at 8:24AM
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