E-mail - Node Spacing Problems

Hi Doc,
What deficiency causes spacing between nodes?

Do you mean long or short nodes? Long nodes can be from applying too much nitrogen or too little light, or too much heat.
Short nodes often result when the plants are in a contain  that is too small (see potting up link) but can be from a phosphorus deficiency which is rare but can cause short plants.  The short plants will be dark green and may turn purple (including the stems). Phosphorus is the second number in a fertilizer (N-P-K) so make sure you use a fertilizer that has phosphorus as it improves root growth in young plants, and fruit/flowering in older plants.  Never use more than the manufacturers recommended dose however! Even if you are using a fertilizer with phosphorus if your pH is above 7.3 or below 5 your plants may not be able to get phosphorus so you should check your pH.

Hope this helps
Good Growing,
Dr. E.R. Myers


E-mail Set up of Filter, Reflector and Fan

Hello There Doc,
  I have a small grow enclosure (2x4x5) with a 400w hps air cooled reflector and a 4" inline fan for air exchange with a carbon filter. i was just wondering what the most efficient way to incorporate all these items. For example what is the best order to use these items. filter-reflector-fan. all obviously connected with 4" ducting. will this reduce the efficiency of the filter at all? and how air tight are the reflectors with a glass lens? odor and heat must be controlled. Thank you

Thanks for your E-mail. I have forwarded your question to Perry at Sales@HTGSupply.com. He is better qualified to answer questions about equipment while I answer any questions about plants and the environment you create to grow plants. If you have any biological questions please send me another E-mail
Good Growing,
Dr. E.R.Myers

From Perry at Sales@ HTGSupply.com
Thank you for your purchase. I got this question forwarded from our ASK THE DOC section. He deals with just actual growing questions and that is why he forwarded this to me.
Your idea for most efficient way to set those up is correct,” filter-reflector-fan". The manufacturers of both the filters and the fans, regardless of whom the manufacturer is, recommend having the fan at the very end pulling air threw then out the fan. Just like you mentioned! The reason being if set up so the fan is "pushing" the air through, there will be resistance from the ducting and reflector that will slow down the CFM, thus you won't get the same performance. However, if it is "pulling" at the end then out the fan, the resistance isn't as bad thus you get better performance.

Thanks again and have a nice day
Shipping Manager


E-mail -- Worm Castings and Soil Amendments

Hello Doc,

I’m doing a soil mixture of : soil, perlite, peat moss, and worm castings. How much of each in a two gallon pot. Specifically the worm castings, a few cups each, or a few ounces each? please help.

The good news is that you can not really use too much worm castings. Many places recommend up to 10-30% of your medium consist of worm castings. You could start by adding 2 cups of castings per 1 gallon and see how the plants do with that.  (There are 16 cups in a gallon so 2 cups per gallon would be 12.5% worm castings)  I would also recommend using coir instead of peat moss, as coir is a renewable resource and peat moss is basically mined from wetlands.  Either one can make your medium more acidic so you need to keep an eye on that.  Adding some lime to your mixture (1 table spoon per gallon of medium) will help keep the pH in a good range.
Ultimately, how much of any medium amendment you use will depend on the type of plant you grow, plants that need lots of fertilizer you can use three or more cups of worm casting per gallon, plants that do not need nutrients as much you can give less.
You could also do a little experiment and give some plants more worm castings and see if you can notice a difference. That way you will know what *you* need for *your* plants.
Good growing,
Dr. E.R. Myers


Light, Photosynthesis and LED’s -- I

There is some confusion about LED’s so some background information on light to get started: The first step in photosynthesis (where light energy is converted to chemical energy for the plant to use to grow and flower etc.) is the absorption of light. Pigments are any substance that absorbs visible light. No pigment can absorb all types of visible light. Visible light is also called white light since all the colors of the rainbow (red, orange, yellow, green. blue and violet) together look white to our eyes. You can see these separate colors when white light passes through a prism. A prism separates white light into colors because each color is actually a type of energy with a slightly different wavelength and so each passes thought the prism differently and separates.

Ok, now that you have the background, Plants have many pigments but the most common one is called chlorophyll, it is what makes them green since all light accept green is absorbed by chlorophyll. The light absorption pattern of a pigment is called the absorption spectrum. The absorption spectrum is not the same for all colors, it has been shown since 1800’s and again many times that red and blue are absorbed more than other colors by chlorophyll. Now this is not the end of the story… the action spectrum is the relative effectiveness of different wavelengths (colors) to elicit specific processes such as flowering or phototropism (plant moving toward light). The similarity between the absorption spectrum and the action spectrum is evidence that specific pigments are responsible for that process.

Now here is where the confusion comes with LED’s. LED’s are very efficient light sources one reason being they emit light in a very narrow band (wavelength) Light wavelengths are measured in nanometers (a nanometer is one billionth of a meter- chop up a meter stick into 1 billion equal pieces). The confusion stems from the fact the pigments in our eyes are NOT the same as the pigments in plants. So, what we see as red or blue might not be the exact wavelength, measured in nm, that is going to elicited the maximum action spectrum for plants. In other words, just because an LED looks red or blue to your eyes does not mean it is the best wavelength of light for plant growth.

This is where HTGSupply.com has done their homework. The TriBand system has been created to generate light that is in the optimal range for absorption spectrum which will lead to the maximum action spectrum (This leads to maximum growth and flowering). Here is what you need to understand… Just because two LED’s look similar (have similar shape and design) does not mean they are the same. You can have two Corvettes that have two different engines and while they look the same, they certainly won’t drive the same. HTGSupply.com created their TriBand when they began consulting me, they wanted to make an LED that was the best for plant growth. I know they grow and test plants with all their lights, and so do I (Best LED LINK -- 2nd tested LED LINK). If you are not sure about growing with an LED, I can’t speak for any other company, but I can and have seen the TriBand lights grow plants from seed to flower and I have used it for cloning, this technology works.
Good Growing,
Dr. E.R. Myers


E-mail --Confused about LED

Hey there Doc,
   All of this online pro and con info. has my head spinning, regarding LED grow lights. It seems that as long as the light is usable for the plants, it doesn't matter whether it comes from an LED, HPS, MH, or outer space! I need a new vegetative light and I have seen more than one positive comment about HTG Supply. I was hoping you could recommend an LED panel or UFO system that you have found effective. I will gladly order one, once my confidence has received a little boost. I need about 12 sq. feet of good intense coverage. Thanx mucho!!!

I have done a good bit of research into LED since HTGsupply.com first contacted me. I am with you, it seems a bit confusing, and a big reason is that not all LED’s are the same. I am still an HID specifically HPS grower and LED’s don’t seem to be better than HPS for my growing needs.  However, they do use less electricity (which is good) and have a lower heat output.  Also, for large areas you would need multiple LED’s where as one 600W or 1000 W HPS can do the trick. This means you would spend more money on a couple-three LED’s if you have a larger area (5x5 or bigger). However, if you used 400 W of LED and compared that to 400 W HPS then I would not bet against LED’s to win. However the initial cost would be a lot more for LED, but the life of an LED is years more than an HPS so that must be figured in too…

What I can tell you is I have grown using the 120 watt tri band and I am using the new 90 UFO with 2 Watt LED bulbs and it is looking good (It has the same new Triband technology)  I know LED lights are VERY popular items and have shown excellent results (LINK to UFO test).

I also used the UFO for clones (LINK CLONE BUCKET) and I had great results. I would say if you are going to use an LED, I would recommend the newer 2 watt bulbs and using the Tri-band technology from HTGSupply.com. There are a lot of other LED’s out there, but many other companies simply buy the parts from China and have no over sight or testing. I am glad to test many of HTGSupply’s stuff, and I have been happy with everything, accept the ozone generator (LINK). I know the owners care first and foremost about their customers having good products where as many other companies would rather make a quick buck and sell you a crappy product and try to find another sucker. I say go with a Tri Band LED from HTGsupply.com and you won’t need to go anywhere else.
Good Growing,
Dr. E.R.Myers