Collected Q&A from Readers’ Emails, Part 5


1. In the fifth week of flower, the strain I grow ‘fox tails.’ Is there something specific that is causing this that I can correct, or is it in the plant’s genetics and I’m just SOL?

I am assuming that by “fox tail,” you mean that the buds become airy rather than remaining dense (that is, internodal length becomes unacceptably long). I am also assuming that you are not doing anything strange—such as growing under some unusually blue source of light or applying hormones. Finally, I am taking a clue from the regularity you are indicating: you have reported that this always occurs in the fifth week, suggesting genetic tendency.

Plant cell elongation is cause by two physical forces: the pressure of water in the cell (turgor) and the yield resistance of the surrounding cellulosic fibers. Plant cells in the apical meristem are isodiametric (spherical) at first and then begin to elongate as the cellulose microfibrils’ transverse orientation forces the cells to elongate as the cellulose resists outward pressure (imagine a ballon inflating inside a length of pipe). If you are not doing anything to change this, it is all in the genetic programming of the plant.

Remember that all you can ever do to grow great weed is to provide the conditions that allow your plant to live up to its genetic potential. After that, it’s up to the plant. Feeding a Poodle prime rib won’t turn it into a German Shepherd. That said, airy plants can still be quite potent—all you are missing is good looks (that’s what she said). You need a new strain if bag appeal is something you want.

LEDs vs HIDs

2. Do LED lights work better than HIDs?

Your primary objective is to provide a source of light that is intense in the 400-500nm and 600-700nm color ranges at about 1200-1500µmol/m2/s1 intensity with the least amount of electricity. But, you may have other objectives I don’t know about.

The answer to your question depends on the quality and intensity of the lights and your application. What are you doing? Do you have a commercial op where your electric bill is killing your cost/gram or your employees are sick of yellow light? Do you need stealth?

Right now, LED’s are getting good, but as far as I am aware have not surpassed HPS (this is a matter for metrics, not opinion—I haven’t seen an LED that outperforms an HPS watt for watt). I am intrigued by the new Ceramic Metal Halides (CMH), which I have seen deployed commercially with good results and will undoubtedly improve in the near future. These CMH’s provide a light that plants like and that is not offensive to human eyes—a serious consideration when you work under them everyday, all day. (Horticultural LED’s are a disaster for human sight, requiring supplemental white light in order to work and make visual assessments of plant health.)

For now, a 600-watt HPS is still your best (most cost-effective and best all-around color) bet for a legal home grow. Because of their low heat output and (generally) lower absolute electrical consumption, LED’s are hard to beat when nosey neighbors are a concern. Blending HPS and CMH in a commercial setting is worthwhile for the improved visual conditions for your workers.

Are there “Advanced” Nutrients?

3. Many lines of nutrients claim they’re ‘advanced.’ What makes them advanced and are they really better than all the others?

Some formulations can be better than others, yes. But that has to do with how accessible the compounds are to the plant and nothing to do with the nutrients they provide. Let’s examine the claim a bit more closely. A plant can use 19 nutrients in their inorganic, ionic form, and that is the end of that discussion. They may be provided as organic, meaning that they have a carbon ring attached to them, but these compounds must be stripped of their carbon before the plant can use them. Alas, an organically-grown plant is itself no different from a traditionally-grown plant. Therefore, the term “organically-grown” has no chemical or botanical meaning, only political and marketplace ones.

Similarly, a manufacturer may provide a certain compound, for example, nitrogen could be supplied as NH4+ or NO3 – , then claim that one is better than the other, or suggest that by having both their product is “advanced,” but this is only half-true. Providing both the negatively and positively charged forms of nitrogen is indeed beneficial because it balances the cations and anions in the plant, but it’s misleading to suggest that either of these compounds is special in and of itself. These compounds are both sources of nitrogen the plant can use—how could one be more “advanced” than the other? The fact growers should remember is this: the nutrient that gets taken up by the plant is the same, no matter the source. Chemicals are cheap. There is no need to pay a fortune for “advanced” formulas.

Below is an exhaustive list of the non-mineral and mineral nutrients a plant can use (and needs) to grow. Supply them any way you like.

Nutrients from Air and Water (non-mineral macros):

    Hydrogen (H)
    Carbon (C)
    Oxygen (O)

Primary Macronutrients:

    Nitrogen (N)
    Phosphorus (P)
    Potassium (K)

Secondary Macronutrients:

    Calcium (Ca)
    Sulphur (S)
    Magnesium (Mg)
    Silicon (Si)


    Chlorine (Cl)
    Iron (Fe)
    Boron (B)
    Manganese (Mn)
    Sodium (Na)
    Zinc (Zn)
    Copper (Cu)
    Nickel (Ni)
    Molybdenum (Mo)

Author’s Note: These questions originally appeared in my column in the November issue of Sativa Magazine.

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