A common inquiry.
From ambitious new gardeners and for good
reason too. But, this is really a loaded question that doesn't have a
definite answer. It seems one of the first assumptions by new gardeners
is that loads of light automatically equals loads of buds.
Unfortunately, it's just not that simple. Yield is equally contingent
on a number of factors; light, temperature, humidity, water, nutrients,
CO2/ventilation, genetics, etc. Think of it as an engine, with each
factor of cultivation representing a single piston, sure the engine
will run if some of the cylinders are misfiring or not firing at all,
but to yield the most power from that engine, all cylinders must be
firing in sync and at maximum capacity.
Temperature. Most cannabis plants will slow or cease growth
when temp's get above 85F, or below 65f. Optimal lights-on temp for
most strains is about 72-78F, with 5-10 degrees cooler during the dark
period being a good rule of thumb.
Humidity. Cannabis does best around 45%-55% RH (relative humidity).
During veg and late flower, however letting it drop lower during
the final two weeks of flower is advised, as it will help prevent mould
Water/moisture. Cannabis generally doesn't like "wet feet",
or a soggy environment, so it's very important to have a fast draining
soil/soil-less mix (or well aerated solution in a hydro garden). Wet or
damp conditions can also lead to mould problems during flowering.
Nutrients. Cannabis will require a variety of nutrients at
varying NPK ratios during its existence. NPK stand for; nitrogen (N),
phosphorus (P), and potassium (K)-the three major nutrients used by
plants. Simply put, your plants will need a fertilizer with more N than
P and K during vegetative growth and fertilizer with more P than N and
K during flowering. Using any well-known quality fertilizer applied per
instruction @ ½ strength is a good place to start. Organic, chemical,
or somewhere in-between is another choice to be made and is a totally
personal one. There is a plethora of fertilizers on the market, but the
best fertilizer is the one that's used properly.
CO2/ventilation. Plants require CO2. There is sufficient CO2
in our atmosphere to support massive bud growth, but when growing
inside you must either have adequate ventilation (the volume of the
room exhausted at least once/5 minutes) to ensure that there is a
constant supply of fresh, CO2 enriched air or one must have
supplemental CO2, which requires higher temp's and more nutrients to be
Light. Typically, the more the merrier, but more light will
create stronger water, nutrient, and CO2 demands on the plants. You
must also have the proper spectrum of lighting as well as a means of
efficiently reflecting as much of the light as possible into the
garden\'s canopy. The norm is to use more bluish light (Metal Halide,
cool-white fluorescents) for vegetative growth and more reddish (High
Pressure sodium, warm fluoro's) light for flowering. Though it's
possible to grow great buds under fluorescent lighting and a few will
even argue their superiority to HID's, most indoor growers use High
Intensity Discharge lights such as MH and HPS, and many use fluoro's
for vegetative growth and HPS for flowering. It's very important to
have the light as physically close to the canopy as possible without
burning the foliage and still allowing for even coverage.Many new
growers believe that "Droppin the light" closer to the plant will be
beneficial. Besides heat stress, the bulb puts out radiant energy that
causes leaf burn (Note it is possible to complete a grow using just HPS
Genetics. Its an easily overlooked factor. Some strains
simply have the potential to yield more than others. Having a
heavy-yielding strain doesn't automatically equal big yields, either.
It only means that the potential for heavy yields is there. The grower
must provide the optimum environment for that particular strain in
order for it to be able to reach it's yield potential, and each strain
has slightly unique requirements. Also, within a strain there are
usually several phenotypes, each of which will exhibit unique
characteristics which is to say that some pheno\'s of a particular
strain will weigh more than others.
Plant/root/container size. Obviously, the longer a plant is
veg'd, the bigger it will get and the more it will yield. Almost always
overlooked because they're unseen are the roots. Root mass is directly
related to bud production. Simply put, the more roots you have the more
bud you will (potentially) have. Be sure to always allow plenty of
space for the roots to grow and spread out, even more-so in soil A
general rule of thumb is 1 gallon of soil for every foot of plant
These systems have a higher g/w/time yield than comparable large plant system over the same time period.
Grower's skill. Growers can add yield by: using additives (like B1, kelp, enzymes), foliar feeding, and topping/FIM/
Tricks like keeping nutrients and the air temps
warm during night cycle can help final yield. Although it's a topic of
hot debate, it's generally thought that any system that supplies the
roots with maximum oxygen (aeroponics) would outperform a system that
restricts 02 input such as (soil).
So, as you can see there's much more to yield than throwing some
plants under tons of light with tons of nutes. Before one becomes too
concerned with yield, one must first learn how to grow plants well,
learn how to "listen" to the plants and give them just what they need.
It's best to start with simpler methods, in fact, I think the simpler
method is always the better one. Learn how to grow strong, healthy,
fast-growing plants and the yields will come.