How to Accurately Measure Your Spectrum

The SPD is a very important factor in plant yield, quality and morphology so should be considered carefully when designing a lamp or purchasing a lamp.

So lets not get too carried away and think that led has magic spectrums that will grow you an award winning plant over night with double the size and weight, even though led spectrum is proven time and time again in both domestic and commercial environments to provide better overall quality a good spectrum will not increase your biomass more 30%.

The average PPFD is calculated using the SPD and therefore dictates the biomass to a certain extent more so thany any other lamp factor. You can see this is evident in the HPS world where high power lamps are producing large yields with spectrums that if compared to a good led spectrum look like they shouldn’t grow anything at all. 

GOD Spectrum 600e Spectrum

The additional oil production from a good SPD increases biomass by providing denser fruits and buds, giving a more efficient yield.  And of course a higher quality end product can attract higher prices or market demand.

SPD is the reason that tier 1 led can beat its HPS counterparts with as little as 70% of the same power consumption, so for example a good quality tier 1 led fixture outputting average 635 µmol/s-m2 average can beat a Professional HPS Fixture (900 µmol/s-m2 average ) in warm to hot environments or controlled environments as long as it provides an equivalent footprint.


A cool running lamp with a good SPD focused on the plant absorption curves can beat its traditional HPS counterparts  for several reasons including:

  1. Better spectrum equals better quality plants with more essential vitamin and oil content giving a higher return per gram.
  2. No excessive heat causing plant stress or burning off essential oils.
  3. Better environmental control, its easier to warm a room than to cool a room.
  4. Less infestation problems as many predators such as spider mites prefer the hotter climates that HPS can provide.
  5. More control of the morphology of your plants due to no restrictions on direct heat in or above your canopy area

A cool running lamp with a good SPD focused on the plant absorption curves can beat its traditional HPS counterparts in total cost of ownership and return on investment for several reasons including:

  1. Repeatable and reliable yields year on year due to absolute minimum light drop from efficiently cooled fixtures allow you to exactly plan your financials.
  2. 30%+ greater essential oil content gives you a greater return on investment.
  3. Lower light source energy consumption by as much as 20 – 30% in high bay applications.
  4. Lower air conditioning costs exponentially.
  5. Lower water consumption and nutrient costs, HPS lamps evaporate nutrients from your grow media exponentially which can also cause imbalance in the feed content of your media.
  6. No bulb replacements for ten years:
    1. Save costs of replacement bulbs (1 bulb every six months = 20 bulbs x £25 = £500 bulb costs over 10 years).
    2. Saves the earth with no toxic landfill.
    3. Maintenance for replacing bulbs in high bay applications can be costly and cost you valuable growing time.
    4. Installation for high voltage HPS lights can be expensive.
 

Measuring Your Spectrum

The best way to know your spectrum is to measure your lamps in an integrated sphere as this then gives you a 99 - 100% accurate average SPD you can work from.

Using hand held meters gives only a rough guide to the the spectrum of the plant but can be a useful indicator to see how the SPD can change over distance to help fine tune your plants different growth stages via logisitics instead of dynamics. You can not use these results to calculate your average PPFD